Re-vendor the canonical files from sneak/prompts at e3f79c4 (closes #221 )

The vendored dotfiles, REPO_POLICIES.md and the standard scripts are fetched from sneak/prompts commit e3f79c4, with pixa's own entries kept after the standard part. The scripts pass a new CACHEBUST build argument in place of --no-cache and every Dockerfile stage declares it first, so every RUN step reruns while Go's build cache, mounted on the steps that compile, is kept. The lint phase runs golangci-lint v2.14.0, the test phase runs on the Debian Go image, and the build stage takes the version as the policy gives it. The two new lint findings are fixed in the code. Model: opus-5-5
2026-10-15 17:30:29 +00:00
189 changed files with 13018 additions and 18893 deletions
@@ -18,3 +18,4 @@ jobs:
                  # All history and tags, so git describe finds the version tag.
                  fetch-depth: 0
            - run: script/cibuild
            - run: script/docker-smoke
@@ -70,3 +70,4 @@ vendor/
 # Local dev configs
 config.yml
 config.yaml
 config.dev.yml
@@ -1,76 +0,0 @@
 # Repository Rules
 Last Updated 2026-10-27
 These rules MUST be followed at all times. This is very important.
 - Never use `git add -A`. Stage specific changes for a deliberate commit. A
  commit holds one change. After each change, make a commit with a good one-line
  summary.
 - NEVER modify the linter config without asking first.
 - NEVER modify a test to exclude special cases or otherwise make it pass without
  asking first. In almost all cases, change the code, NOT the test. You need
  explicit user approval to modify an existing test. If you think a test needs
  to change, make your case and ask for permission to proceed. Then stop. A bug
  fix may change an existing test without asking only when that test pins
  exactly the behavior the filed bug calls wrong. The change must then move the
  test to the fixed behavior and nothing else. Any other change to an existing
  test needs explicit user approval. Writing NEW tests needs no approval.
 - When linting, assume the linter config is CORRECT. Treat each item the linter
  reports as something that legitimately needs fixing in the code.
 - When running tests, use `make test`.
 - Before committing, run `make check`. It runs `make test`, `make lint` and
  `make fmt-check`. Any issue it finds MUST be resolved before committing,
  unless you are explicitly told otherwise.
 - When fixing a bug, write a failing test for the bug FIRST. Add appropriate
  logging to the test, to make sure the test is written correctly. Commit that.
  Then work on the fix until the test passes, without changing the test further.
  Then commit the fix.
 - When adding a new feature, do the same: write a test first (test-driven
  development, TDD). The test does not need to be very complex. Commit the test,
  then commit the feature.
 - When adding a new feature, use a feature branch. The feature branch reaches
  `next` through a PR that passes review. It is merged only when the feature is
  completely finished and the code is up to standards. The code is up to
  standards when it passes `make check`. The branch is deleted after the merge.
  Only the user merges `next` into `main`.
 - Write `godoc` comments for all exported types and functions as you go along.
 - ALWAYS be consistent in naming. If you name something one way in one place,
  use the EXACT SAME name in every other place.
 - Be descriptive and specific in naming. `al` is bad; `SourceHostAllowlist` is
  good. `ConnsPerHost` is bad; `MaxConnectionsPerHost` is good.
 - This is not prototype or teaching code. It is designed for production. Any
  security issue (such as denial of service) or other web vulnerability is a P1
  bug. It must be added at the top of `TODO.md`.
 - Do not stub an implementation unless you are specifically instructed to. This
  is production code, and we need working implementations.
 - NEVER silently fall back to a different setting when a user's parameter
  explicitly specifies a value. For example, if a user requests `format=webp`
  and WebP encoding is not supported, return an error. Do NOT silently output
  PNG instead. If a user specifies `fit=invalid` and that fit mode does not
  exist, return an error. Do NOT silently default to `cover`. A silent fallback
  violates the principle of least surprise and masks bugs. Defaults are
  acceptable only for OMITTED parameters, never for INVALID explicit values.
 - Avoid vendoring dependencies unless specifically instructed to. NEVER commit
  the `vendor/` directory. NEVER commit compiled binaries. If such a directory
  or file exists and `.gitignore` does not list it, add it to `.gitignore`.
  Commit that `.gitignore` change. Keep the entire git repository, history
  included, under 20 MiB. Go over 20 MiB only when you specifically must commit
  a large file, such as a media file used as a test fixture. Only OUR source
  code and its immediately supporting files, such as test examples, go into the
  repository and its history.
@@ -0,0 +1,71 @@
 # Repository Rules
 Last Updated 2026-01-08
 These rules MUST be followed at all times, it is very important.
 - Never use `git add -A` - add specific changes to a deliberate commit. A commit
  should contain one change. After each change, make a commit with a good
  one-line summary.
 - NEVER modify the linter config without asking first.
 - NEVER modify tests to exclude special cases or otherwise get them to pass
  without asking first. In almost all cases, the code should be changed, NOT the
  tests. If you think the test needs to be changed, make your case for that and
  ask for permission to proceed, then stop. You need explicit user approval to
  modify existing tests. (You do not need user approval for writing NEW tests.)
 - When linting, assume the linter config is CORRECT, and that each item output
  by the linter is something that legitimately needs fixing in the code.
 - When running tests, use `make test`.
 - Before commits, run `make check`. This runs `make lint` and `make test` and
  `make check-fmt`. Any issues discovered MUST be resolved before committing
  unless explicitly told otherwise.
 - When fixing a bug, write a failing test for the bug FIRST. Add appropriate
  logging to the test to ensure it is written correctly. Commit that. Then go
  about fixing the bug until the test passes (without modifying the test
  further). Then commit that.
 - When adding a new feature, do the same - implement a test first (TDD). It
  doesn't have to be super complex. Commit the test, then commit the feature.
 - When adding a new feature, use a feature branch. When the feature is
  completely finished and the code is up to standards (passes `make check`) then
  and only then can the feature branch be merged into `main` and the branch
  deleted.
 - Write godoc documentation comments for all exported types and functions as you
  go along.
 - ALWAYS be consistent in naming. If you name something one thing in one place,
  name it the EXACT SAME THING in another place.
 - Be descriptive and specific in naming. `wl` is bad; `SourceHostWhitelist` is
  good. `ConnsPerHost` is bad; `MaxConnectionsPerHost` is good.
 - This is not prototype or teaching code - this is designed for production. Any
  security issues (such as denial of service) or other web vulnerabilities are
  P1 bugs and must be added to TODO.md at the top.
 - As this is production code, no stubbing of implementations unless specifically
  instructed. We need working implementations.
 - NEVER silently fall back to a different setting when a user's parameter
  explicitly specifies a value. If a user requests format=webp and WebP encoding
  is not supported, return an error - do NOT silently output PNG instead. If a
  user specifies fit=invalid and that fit mode doesn't exist, return an error -
  do NOT silently default to "cover". Silent fallbacks violate the principle of
  least surprise and mask bugs. The only acceptable defaults are for OMITTED
  parameters, never for INVALID explicit values.
 - Avoid vendoring deps unless specifically instructed to. NEVER commit the
  vendor directory, NEVER commit compiled binaries. If these directories or
  files exist, add them to .gitignore (and commit the .gitignore) if they are
  not already in there. Keep the entire git repository (with history) small -
  under 20MiB, unless you specifically must commit larger files (e.g. test
  fixture example media files). Only OUR source code and immediately supporting
  files (such as test examples) goes into the repo/history.
@@ -1,16 +1,12 @@
-# In every stage ARG CACHEBUST comes right after the steps that install
+# Every stage declares ARG CACHEBUST first: script/ passes a new value
-# system packages and download Go's modules, or right after FROM in a
+# on every build, which reruns every RUN step after it. The steps that
-# stage with neither, and every step that lints, tests or compiles
+# compile mount Go's build cache, which survives from build to build.
 # comes after it. script/ passes a new value on every build, which
 # reruns every RUN step after it. Docker keeps the layers above it
 # until the base image, their own lines or go.mod and go.sum change.
 # The steps that compile mount Go's build cache, and golangci-lint run
 # also mounts golangci-lint's; both survive from build to build.
 # Lint phase. script/lint builds it alone. The linter is run directly:
 # `make lint` and script/lint are themselves a docker build.
 # golangci/golangci-lint:v2.14.0, 2026-10-15
 FROM golangci/golangci-lint@sha256:ad862ba6b3798cbe0fd9fd7408d498fd74fbd2623a92406b2fd3898faf0bf98f AS lint
 ARG CACHEBUST
 # The linter compiles every package, and govips needs the libvips
 # headers for that. REPO_POLICIES.md has the lint phase install them
@@ -22,29 +18,25 @@ RUN apt-get update \
 WORKDIR /src
 COPY go.mod go.sum ./
 RUN go mod download
 ARG CACHEBUST
 COPY . .
 RUN --mount=type=cache,target=/root/.cache/go-build \
    --mount=type=cache,target=/root/.cache/golangci-lint \
    golangci-lint run --config .golangci.yml ./...
 # Test phase. script/test builds it alone. -race needs cgo and so a C
 # compiler, which the Debian Go image ships and the alpine one does not.
 # golang:1.25.4-trixie, 2026-10-15
 FROM golang@sha256:a02d35efc036053fdf0da8c15919276bf777a80cbfda6a35c5e9f087e652adfc AS test
-
+ARG CACHEBUST
 # govips compiles against the libvips and libheif headers, and the tests
 # need libvips' JPEG XL support; libvips-dev brings all three. The tests
 # also encode AVIF, which needs libheif's AVIF encoder,
 # libheif-plugin-aomenc: Debian only recommends it, so it is named here.
 RUN apt-get update \
    && apt-get install -y --no-install-recommends libvips-dev libheif-plugin-aomenc \
    && rm -rf /var/lib/apt/lists/*
 WORKDIR /src
 # script/bootstrap --cgo installs the build dependencies (the libvips
 # and libheif headers, and libvips' JPEG XL support, which the tests
 # need) and downloads the Go modules.
 COPY script/ ./script/
 COPY go.mod go.sum ./
-RUN go mod download
+RUN script/bootstrap --cgo
-ARG CACHEBUST
+
 COPY . .
 # Without -v first; on a failure, again with -v for the details, and
@@ -60,23 +52,22 @@ RUN --mount=type=cache,target=/root/.cache/go-build \
      go test -count=1 -timeout 90s -race -parallel 4 -v ./...; exit 1; }
 # Build stage. Nothing is wanted from the two phases above: these copies
-# make BuildKit build them first, so nothing after them runs unless lint
+# make BuildKit build them first, so this stage runs only when lint and
-# and test passed.
+# test passed.
 # golang:1.25.4-alpine3.22, 2026-02-25; the runtime stage uses Alpine 3.22 too
 FROM golang:1.25.4-alpine3.22@sha256:d3f0cf7723f3429e3f9ed846243970b20a2de7bae6a5b66fc5914e228d831bbb AS builder
 # git for the version, and for govips a C compiler, pkg-config and the
 # libvips and libheif headers
 RUN apk add --no-cache git build-base pkgconfig vips-dev libheif-dev
 WORKDIR /src
 COPY go.mod go.sum ./
 RUN go mod download
 ARG CACHEBUST
 COPY --from=lint /src/go.sum /dev/null
 COPY --from=test /src/go.sum /dev/null
 WORKDIR /src
 # Build dependencies, git among them, and Go modules, as in the test
 # phase
 COPY script/ ./script/
 COPY go.mod go.sum ./
 RUN script/bootstrap --cgo
 # A tar-stream context keeps the sender's file owners, which git refuses.
 RUN git config --system --add safe.directory /src
@@ -111,6 +102,7 @@ RUN --mount=type=cache,target=/root/.cache/go-build \
 # the libvips and musl it was built with.
 # alpine:3.22, 2026-10-08
 FROM alpine:3.22@sha256:5291449c3df73caf6ed85e649dec1b9e818b39a5d8c871e97afc13e9cd5e8fa8
 ARG CACHEBUST
 # Install runtime dependencies only. vips-jxl is libvips' JPEG XL
 # support, without which pixad does not start.
@@ -121,7 +113,6 @@ RUN apk add --no-cache \
    ca-certificates \
    tzdata \
    su-exec
 ARG CACHEBUST
 # Copy binary from builder
 COPY --from=builder /pixad /usr/local/bin/pixad
@@ -1,4 +1,4 @@
-.PHONY: bootstrap setup check lint test fmt fmt-check build clean docker docker-smoke docker-versioned docker-test devserver devserver-stop hooks loadtest bench
+.PHONY: bootstrap setup check lint test fmt fmt-check build clean docker docker-smoke docker-versioned docker-test devserver devserver-stop hooks loadtest
 VERSION := $(shell git describe --tags --always --dirty 2>/dev/null || echo "dev")
 LDFLAGS := -X main.Version=$(VERSION)
@@ -64,12 +64,6 @@ docker-smoke:
 loadtest:
 	@script/loadtest
 # Serve cache hits in parallel through the image handler and report hits per
 # second (needs Go on the host after `script/bootstrap --cgo`, not Docker; a
 # benchmark, not part of check)
 bench:
 	@script/bench
 # Build Docker image as `make docker` does, and also tag it pixa:$(VERSION)
 docker-versioned:
 	@script/docker
@@ -79,15 +73,12 @@ docker-versioned:
 docker-test:
 	@script/test
-# Run local dev server in Docker, with debug on and a new random signing
+# Run local dev server in Docker
 # key each run. Log in to the page with the key it prints.
 devserver: docker-versioned devserver-stop
 	@key="$$(head -c 32 /dev/urandom | base64)" && \
 	docker run -d --name pixad-dev -p 8080:8080 \
-		-e PIXA_SIGNING_KEY="$$key" -e PIXA_DEBUG=true \
+		-v $(CURDIR)/config.dev.yml:/etc/pixa/config.yml:ro \
-		pixa:latest >/dev/null && \
+		pixa:latest
-	echo "pixad running at http://localhost:8080" && \
+	@echo "pixad running at http://localhost:8080"
 	echo "signing key: $$key"
 # Stop dev server
 devserver-stop:
@@ -1,6 +1,6 @@
 ---
 title: Repository Policies
-last_modified: 2026-10-18
+last_modified: 2026-10-15
 ---
 This document covers repository structure, tooling, and workflow standards. Code
@@ -159,11 +159,8 @@ style conventions are in separate documents:
    one's findings, and a host-global lock in `$TMPDIR` makes concurrent runs
    exit non-zero with `parallel golangci-lint is running` — a status a caller
    cannot tell from real findings. Both have produced wrong verdicts in this
-    org, in both directions. A container has its own `TMPDIR`, so the lock is
+    org, in both directions. A container has its own golangci-lint cache, its
-    out of reach. The lint phase does keep golangci-lint's cache between check
+    own `TMPDIR` and a digest-pinned binary, so neither is reachable.
    builds (below), but it lints every checkout at `/src`, and a finding is
    taken from that cache only for the same files, settings and golangci-lint
    version.
 - **Any build that runs checks is given a new `CACHEBUST` value.** Docker
  invalidates a `COPY` layer only when the copied content changes, so on an
@@ -173,21 +170,15 @@ style conventions are in separate documents:
  id, so no two builds share a value, not even the three in one
  `script/cibuild`. `script/lint`, `script/test`, `script/cibuild` and
  `script/docker` are the four, and there is no fifth — `script/check` runs the
-  two gate phases and `script/fmt-check`, and builds no image of its own. In
+  two gate phases and `script/fmt-check`, and builds no image of its own. Every
-  every stage of the `Dockerfile`, `ARG CACHEBUST` comes right after the steps
+  stage of the `Dockerfile` declares `ARG CACHEBUST` as its first line after
-  that install system packages and download Go's modules, or right after `FROM`
+  `FROM`, and a new value reruns every `RUN` step after that line; `COPY` steps
-  in a stage with neither, and every step that lints, tests or compiles comes
+  are compared by content and need nothing. A stage without the `ARG` line is
-  after it. A step that installs anything else as well, such as a
+  served from cache on an unchanged tree, so a repository re-vendors the scripts
-  `script/bootstrap` that also installs node packages, comes after it too. A new
+  and adds the `ARG` lines in one commit. The scripts do not pass `--no-cache`:
-  value reruns every `RUN` step after that line; `COPY` steps are compared by
+  it reruns every step too, but it also empties every cache mount, and Go's
-  content and need nothing. Docker keeps the layers above the line until the
+  build cache, which the canonical Go `Dockerfile` below mounts so that compiled
-  base image, their own lines or the files they copy change. A stage without the
+  packages survive between check builds, would start empty every time. A bare
  `ARG` line is served from cache on an unchanged tree, so a repository
  re-vendors the scripts and adds the `ARG` lines in one commit. The scripts do
  not pass `--no-cache`: it reruns every step too, but it also builds the layers
  above the line again and empties every cache mount, so Go's build cache and
  golangci-lint's, which the canonical Go `Dockerfile` below mounts so that they
  survive between check builds, would start empty every time. A bare
  `docker build .` is not evidence that anything ran: a sub-second build
  reporting success is a cache hit, not a result. Never invalidate by pruning —
  `docker builder prune` and friends destroy a build cache shared with every
@@ -203,25 +194,19 @@ style conventions are in separate documents:
  `Dockerfile`:
    ```dockerfile
-    # In every stage ARG CACHEBUST comes right after the steps that install
+    # Every stage declares ARG CACHEBUST first: script/ passes a new value
-    # system packages and download Go's modules, or right after FROM in a
+    # on every build, which reruns every RUN step after it. The steps that
-    # stage with neither, and every step that lints, tests or compiles
+    # compile mount Go's build cache, which survives from build to build.
    # comes after it. script/ passes a new value on every build, which
    # reruns every RUN step after it. Docker keeps the layers above it
    # until the base image, their own lines or go.mod and go.sum change.
    # The steps that compile mount Go's build cache, and golangci-lint run
    # also mounts golangci-lint's; both survive from build to build.
    # Lint phase
    # golangci/golangci-lint:v2.x.x, YYYY-MM-DD
    FROM golangci/golangci-lint@sha256:... AS lint
    ARG CACHEBUST
    WORKDIR /src
    COPY go.mod go.sum ./
    RUN go mod download
    ARG CACHEBUST
    COPY . .
    RUN --mount=type=cache,target=/root/.cache/go-build \
        --mount=type=cache,target=/root/.cache/golangci-lint \
        golangci-lint run --config .golangci.yml ./...
    # Test phase. -race needs cgo and so a C compiler, which the Debian Go
@@ -229,10 +214,10 @@ style conventions are in separate documents:
    # cache also holds test results, which go test would otherwise replay.
    # golang:1.x, YYYY-MM-DD
    FROM golang@sha256:... AS test
    ARG CACHEBUST
    WORKDIR /src
    COPY go.mod go.sum ./
    RUN go mod download
    ARG CACHEBUST
    COPY . .
    RUN --mount=type=cache,target=/root/.cache/go-build \
        go test -count=1 -timeout 90s -race -cover ./... || \
@@ -240,19 +225,19 @@ style conventions are in separate documents:
          go test -count=1 -timeout 90s -race -v ./...; exit 1; }
    # Build stage. Nothing is wanted from either phase above; the copies
-    # are what make BuildKit build them first, so nothing after them can
+    # are what make BuildKit build them first, so this stage cannot run
-    # run unless lint and test passed.
+    # unless lint and test passed.
    # golang:1.x-alpine, YYYY-MM-DD
    FROM golang@sha256:... AS builder
    RUN apk add --no-cache git
    WORKDIR /src
    COPY go.mod go.sum ./
    RUN go mod download
    ARG CACHEBUST
    COPY --from=lint /src/go.sum /dev/null
    COPY --from=test /src/go.sum /dev/null
    RUN apk add --no-cache git
    # A tar-stream context keeps the sender's file owners, which git refuses.
    RUN git config --system --add safe.directory /src
    WORKDIR /src
    COPY go.mod go.sum ./
    RUN go mod download
    COPY . .
    # The VERSION build arg when one is given, otherwise
@@ -289,26 +274,16 @@ style conventions are in separate documents:
    - Keep the runtime stage last, and if you add a stage after it, give it the
      same two copies. A plain `docker build .` builds the last stage's chain
      and nothing else.
-    - Check builds keep these, and none of them can hand back a stale result:
+    - Only Go's build cache is mounted (`/root/.cache/go-build`, where Go keeps
-        - The layers above `ARG CACHEBUST`: the system packages and Go's
+      it for root), and only on the steps that compile: `golangci-lint run`,
-          modules. Docker installs the packages again when the base image or the
+      both `go test` runs and `go build`. It keeps compiled packages between
-          install line changes, and downloads the modules again when `go.mod` or
+      check builds, and Go reuses one only when all its inputs are unchanged, so
-          `go.sum` changes. Go checks every module against `go.sum` as it
+      it saves the compile without skipping a check. Nothing else is kept:
-          downloads it, and no later build can change a kept layer. The modules
+      golangci-lint's own cache would replay stored findings in place of a lint
-          are kept in a layer rather than a cache mount because a cache mount is
+      run, and Go builds from whatever files a kept module cache holds without
-          shared by every build on the host, and Go builds from whatever files
+      checking them again (only `go mod verify` does), so a file changed there
-          it holds without checking them again (only `go mod verify` does), so a
+      would go unnoticed. Go's build cache also holds test results, which is why
-          file changed there would go unnoticed.
+      both `go test` runs carry `-count=1`.
        - Go's build cache (`/root/.cache/go-build`, where Go keeps it for
          root), mounted on the steps that compile: `golangci-lint run`, both
          `go test` runs and `go build`. Go reuses a compiled package only when
          all its inputs are unchanged. The cache also holds test results, which
          is why both `go test` runs carry `-count=1`.
        - golangci-lint's cache (`/root/.cache/golangci-lint`, where the pinned
          image keeps it), mounted on `golangci-lint run`. golangci-lint reuses
          a package's findings only when the package's files and those of every
          package it imports, `go.mod`, the linters and their settings in
          `.golangci.yml`, and the golangci-lint version are all unchanged.
    - If the project uses `//go:embed` directives that reference build artifacts
      (e.g. a web frontend compiled in a separate stage), the lint phase must
      create placeholder files so the embed directives resolve. Example:
@@ -317,20 +292,12 @@ style conventions are in separate documents:
      in the lint phase. The `golangci/golangci-lint` image is Debian-based and
      has no `apk`, so install with `apt-get` under the Debian package name
      (`libvips-dev`, where alpine says `vips-dev`), and delete the package
-      lists in the same `RUN`, so the layer does not keep them. The test phase,
+      lists in the same `RUN`, so the layer does not keep them:
      on the Debian Go image, installs the libraries its tests need the same
      way. Either install goes right after `FROM`, above `ARG CACHEBUST`, so
      Docker keeps it until the base image or the install line changes:
        ```dockerfile
        FROM golangci/golangci-lint@sha256:... AS lint
        RUN apt-get update \
            && apt-get install -y --no-install-recommends libvips-dev \
            && rm -rf /var/lib/apt/lists/*
        WORKDIR /src
        COPY go.mod go.sum ./
        RUN go mod download
        ARG CACHEBUST
        ```
    - `.dockerignore` lets `.git` into the build context. It keeps out every git
@@ -2,7 +2,7 @@
 - branch per issue from `next`
 - do the work in Next Step
- delete Next Step from `TODO.md`
+- move Next Step to the top of Completed Steps
 - `TODO.md` merges with git's union merge (`.gitattributes`), which never
  reports a conflict: read the merged entries after every merge or rebase
 - move the top item of Future Steps into Next Step
@@ -16,16 +16,901 @@
 # Status
-pre-1.0. The `1.0.0` milestone is in progress.
+pre-1.0. No git tags exist. The `1.0.0` milestone is in progress; work lands on
 `next`, and `main` receives only the milestone PR that the owner merges. `next`
 is at the canonical `golangci-lint` v2.14.0 config and is green. Recent work
 extracted the internal/magic, internal/allowlist, internal/httpfetcher, and
 internal/signature packages. The gosec findings from the 2026-07-06 survey are
 resolved. The disk cache is now size-bounded with LRU eviction
 (`cache_max_bytes`), closing the unbounded disk growth DoS vector.
 # Next Step
 P2: security: per-origin rate limiting
 # Completed Steps
 - 2026-10-15 the canonical files are re-vendored from `sneak/prompts` commit
  `e3f79c4` (closes #221): `.dockerignore`, `.editorconfig`,
  `.gitea/workflows/check.yml`, `.gitignore`, `.golangci.yml`,
  `.prettierignore`, `.prettierrc`, `REPO_POLICIES.md` and the standard scripts
  are its copies. pixa's own entries follow the standard part: `/bin`, `/data`
  and the local config files in `.dockerignore`; Go's `*.log`, `*.out` and
  `*.test`, `vendor/`, the binaries, `/data/`, `*.sqlite3` and the local config
  files in `.gitignore`. The workflow keeps its `script/docker-smoke` step while
  https://git.eeqj.de/sneak/pixa/issues/203 is open. The scripts pass a new
  `CACHEBUST` build argument in place of `--no-cache`, and every `Dockerfile`
  stage declares it first, so every `RUN` step still runs on every build while
  Go's build cache, mounted on the steps that compile, is kept; both `go test`
  runs keep `-count=1`. The lint and test builds write no image. The lint phase
  runs golangci-lint v2.14.0, the test phase runs on the Debian Go image, and
  the build stage marks `/src` safe for git. `script/bootstrap`, `script/fmt`
  and `script/fmt-check` use the node on the `PATH` only when it has the pinned
  major version. Of golangci-lint v2.14.0's two findings, an unused `nolint`
  directive is removed, and gosec's new path check is marked as not applying to
  the fixed config file locations.
 - 2026-10-15 a transcode stops once its request's `downstream_timeout` has
  ended, unless it has begun encoding (closes #243): the image processor looked
  at its context only while it waited for a processing slot, so an image was
  decoded and encoded, holding the slot, however long after its request's
  deadline that took. `Process` now returns the context's error, and gives the
  slot back, when the context has ended by the time it has the slot or before it
  encodes. A request that waited for a shared transcode stopped at the first
  request's deadline is answered 503 `server busy, try again later`, not 500,
  though its own `downstream_timeout` may not have ended. govips gives pixa no
  way to stop libvips once an encode has begun, so that encode keeps its slot
  until it finishes; the limit of 8192 on each side of the source and of the
  output bounds how long that takes. With one libvips thread, 8192x8192 random
  pixels take up to about 1 second to encode as JPEG, 15 as PNG, 16 as GIF, 63
  as WebP, 110 as AVIF and 96 as JPEG XL, the last three with an alpha channel,
  plus up to about 11 seconds to decode the source; `README.md` gives these
  times and no longer says the work stops when `downstream_timeout` ends. The
  settings of the WebP, AVIF and JPEG XL encoders, which can hold a slot past
  the default `downstream_timeout` of 60 seconds, are unchanged.
 - 2026-10-15 "Running under upaas" in `README.md` tells the operator to set
  `PIXA_CACHE_MAX_BYTES` (closes #251): it listed the variable as optional, but
  under upaas the volume is a directory on the host's filesystem. The default,
  75% of the sum of that filesystem's free space and what the cache holds, and
  at least 500 MiB, let one pixa take three quarters or more of the space the
  host and every other app had left, and all of it when that was 500 MiB or
  less. The section now says so. The default is unchanged.
 - 2026-10-15 the request metrics are labelled by route, not by path (closes
  #254): their `handler` label was each request's path, so every new path, a 404
  or an encrypted URL, added series to the Prometheus registry that were never
  removed, and `/metrics` listed every encrypted URL's token. The label is now
  the pattern of the chi route the request matches, such as `/v1/image/*`, or
  `unmatched` for a request that matches none: one the router answers 404 or
  405, or a CORS preflight. The metrics library takes the label before the
  request is routed, so the metrics middleware asks the router which route
  matches.
 - 2026-10-15 expired negative cache rows are removed on a schedule (closes
  #244): the row of a failed fetch, which makes pixa answer 502 for that source
  URL for 5 minutes, was deleted only when the same URL was requested again
  after that, so a client asking for a new missing path each time added rows
  that stayed for good. The eviction goroutine now calls `CleanExpired` at
  startup and on each periodic tick, every 5 minutes in pixad, so a row stays at
  most about 10 minutes. `CleanExpired` deletes at most 1000 rows per statement,
  so a request waits behind 1000 deletions at most, however many rows have
  expired. The goroutine runs with the disk cache disabled
  (`cache_max_bytes: 0`) too, where it does nothing else, as the negative cache
  is used either way.
 - 2026-10-15 a cached variant is served while its source URL is in the negative
  cache (closes #245): `Get` checked the negative cache before the variant
  cache, so once a fetch of the source failed, as one does when another variant
  misses after the source was evicted and the upstream is down, every variant of
  that source answered 502 for 5 minutes, also one on disk or one that could be
  made from the cached source. The negative cache is now checked only just
  before a fetch from the upstream, so a cached variant is served and a variant
  not in the cache is made from the cached source when there is one. `README.md`
  says so under `/v1/image/`. A refusal from the negative cache now counts as a
  miss, as any other request that misses the variant cache does.
 - 2026-10-15 the host of a `/v1/image/` URL is lower-cased, and one with a port
  needs a signature (closes #246): with `cdn.example.com` allowlisted,
  `CDN.Example.com` and `cdn.example.com:8443` passed the allowlist too, and
  each spelling was fetched and cached on its own and had connections of its own
  under `upstream_connections_per_host`. The image URL parser now lower-cases
  the host and refuses one holding `@`, which a URL reads as a user name and
  password, with 400. A host with a port, or with a `:` and no port, needs a
  signature even when it is allowlisted. That is checked in the image service,
  not in `allowlist.IsAllowed`, which also matches `referer_blocklist`, where a
  `Referer` is blocked whatever its port. A URL is signed over its host as it
  writes it, in lower case, with any IPv6 brackets, `:` and port kept.
 - 2026-10-15 a `:` in the source path or query no longer moves where the path
  ends and the query begins (closes #247): the signed data and the cache key
  joined host, path and query with `:` and no escaping, so a URL signed for
  `https://h/a:b` verified for `https://h/a?b:`; the two also shared a cache
  key, and whichever was fetched first was served for both. In both, the path
  and the query now have each `%` written as `%25` and each `:` as `%3A`; a path
  and query holding neither are signed and keyed as before. Signature
  Specification in `README.md` says so.
 - 2026-10-15 the example config allowlists no host (closes #249): it allowlisted
  `github.com` and `user-images.githubusercontent.com`, where anyone can put an
  image, so a deployment set up as Getting Started says served those images to
  anyone without a signature, at any size and in any format.
  `configs/config.example.yml` now leaves `allowlist_hosts` out, with one
  commented entry under `example.com`. Getting Started and "Running under upaas"
  in `README.md` say that every image on an allowlisted host is served without a
  signature, so an allowlisted host must be one the operator controls.
 - 2026-10-15 a chunked upstream body of exactly `upstream_max_response_size`
  bytes is accepted (closes #248): once the limit was used up, the fetcher's
  next read refused the body without looking for its end. Go's HTTP client
  returns the end of a body sent with a `Content-Length` together with its last
  bytes, but the end of a chunked body can come in a later read, so such a body
  was refused after it had been downloaded whole, and the image routes
  answered 500. Once the limit is used up, the fetcher now reads one more byte:
  if the body has ended it is accepted, and if there is more it is refused with
  `ErrResponseTooLarge`, as before.
 - 2026-10-13 `fit=outside` no longer makes an output above 8192 on a side
  (closes #257): it scales the image to cover the requested size, and the side
  scaled past that size was held to no maximum, so `1x8192?fit=outside` of a
  3000x600 source was resized to 40960x8192 and encoded. The image processor now
  refuses such a size with `ErrOutputTooLarge` before resizing, and both image
  routes answer it 400, as for a size with one side `0`. The other fit modes
  make the requested size or one within it, so none can go above 8192.
 - 2026-10-13 a size with one side `0` no longer makes an output above 8192 on a
  side (closes #241): that side is computed from the source's proportions, and
  nothing held it to the 8192 a requested side is held to, so `0x8192` of a
  3000x600 source was resized to 40960x8192 and encoded. The image processor now
  refuses such a size with `ErrOutputTooLarge` once it knows the source's
  dimensions, before resizing, and both image routes answer it 400 with the JSON
  error body. The refusal is not cached as a failed fetch, so the same source is
  still served at other sizes. `imgcache.MaxDimension` is now the image
  processor's `MaxOutputDimension`, so the two cannot differ.
 - 2026-10-13 the unused cache lifetime is removed (closes #69):
  `CacheConfig.CacheTTL`, which pixad set to `DefaultCacheTTL` (24 hours), was
  never read, so cached images never expired. The field and the constant are
  removed. Cached source and transformed images stay until eviction removes them
  to keep the cache within `cache_max_bytes`.
 - 2026-10-13 SVG sources are refused, and `orig` is never saved as JPEG in place
  of the source's own format (closes #68): the upstream fetch no longer accepts
  `image/svg+xml`, which libvips would render. Both image routes answer 415 for
  an upstream `Content-Type` that is not one of the source formats, SVG
  included, where they answered 500. Before decoding, the image processor
  refuses with `ErrUnsupportedInputFormat`, also answered 415, any input that
  govips' `DetermineImageType`, which picks the libvips loader from the first
  bytes, does not name as a source format. That catches an SVG whose first bytes
  pass the first-bytes check for another type, as an XML comment can make them
  do for AVIF; an SVG whose first bytes do not pass that check answers 500, as
  before, and so does a damaged image in a source format, whose first bytes
  `DetermineImageType` names. `orig` is always the source's own format, where a
  source the processor could not name was saved as JPEG. `README.md` no longer
  lists SVG. The SVG detection in `internal/magic` stays: the request path does
  not call it, and it goes with the unused code of
  https://git.eeqj.de/sneak/pixa/issues/168.
 - 2026-10-12 per-client limit on the image routes (closes #236): the new setting
  `image_requests_per_minute` (`PIXA_IMAGE_REQUESTS_PER_MINUTE`), default 600,
  is how many `GET` and `HEAD` requests one client may send to `/v1/image/` and
  `/v1/e/` together per minute, cache hits included; the next is answered 429
  with `Retry-After`. It uses the login limit's `RateLimit` middleware, so
  clients are told apart the same way, and runs after the CORS middleware, so a
  preflight is not counted. `0` turns the limit off; a negative or non-integer
  value aborts startup.
 - 2026-10-08 a request past its deadline no longer waits for the database to
  count it (closes #224). On a busy host, `TestService_Get_ReturnsByItsDeadline`
  failed because its request, past its deadline, still waited for its miss count
  to be written, a write with no deadline, which in pixad waits for the one
  database connection every request shares. Each count write now keeps the
  request's deadline but not its cancellation. A count not written by then is
  kept in memory, where `Stats` sees it, and one goroutine of the cache writes
  those counts, one write at a time, and once more at shutdown before the
  database closes. The test phase of the `Dockerfile` also runs at most 4 tests
  of a package at once (`go test -parallel 4`), where it ran as many as the host
  has CPUs: on a busy host they then wait so long to be scheduled that a test
  that times a request can fail. `-p`, how many packages are tested at once, is
  unchanged, as capping it also slows compiling.
 - 2026-10-08 every output format is saved with settings pixa sets on purpose
  (closes #232): each format has its own govips export, as JPEG XL does, in
  place of govips' generic `Export`, which sent libvips a zero for some settings
  it was not given. PNG gets libvips' default compression, 6, where it had none,
  and WebP libvips' default effort, 4, where it had 0. GIF was already at
  libvips' default effort, 7, and JPEG output is unchanged. AVIF is saved at
  effort 1, the lowest govips can set, where it had libvips' default, 4. With
  one libvips thread, an 8192x8192 image of random pixels, the worst case, takes
  about 51 seconds as AVIF at effort 1 and 43 as WebP at effort 4, against the
  default `downstream_timeout` of 60 seconds. On an image of milder noise, which
  AVIF at effort 1 saves in about 12 seconds, effort 4 takes minutes. AVIF is
  also saved with 8 bits per sample from a 16-bit source, which libvips would
  save with 12: a 16-bit 8192x8192 image of milder noise takes about 54 seconds
  at effort 1 with 12 bits, nearly all of the default `downstream_timeout`, and
  about 12 with 8.
 - 2026-10-08 JPEG XL is the default output (closes #222): a `/v1/image/` URL
  whose last segment is a size with no format, such as `800x600` or `orig`, is
  served as JPEG XL and signed as `jxl`, so it has the signature of the same URL
  ending in `.jxl`. An encrypted URL whose token holds no format is served as
  JPEG XL (`encurl.DefaultFormat`). The generator page selects JPEG XL until
  another format is chosen, and a form with an empty format, or none, makes a
  JPEG XL URL whose name ends in `.jxl`. The image processor no longer takes an
  empty format as `orig`: both routes give every request a format, and it
  refuses a request with none. `auto` still ends with JPEG.
 - 2026-10-08 JPEG XL as an input and output format (part of #222): a source
  whose bytes start with either JPEG XL signature, the bare codestream's `FF 0A`
  or the container's, is detected as `image/jxl`, which the upstream fetch
  accepts; `orig` of such a source is JPEG XL. The format `jxl` works in plain
  and encrypted URLs and on the generator page, served as `image/jxl` and cached
  like the other formats. `auto` chooses JPEG XL first when `Accept` names
  `image/jxl`. govips sends libvips a JPEG XL distance with every save, so
  libvips ignores the quality: pixa turns `q` into a distance with libvips' own
  formula, keeping 100 lossy, and removes the metadata from the image before
  saving, as govips cannot have libvips strip it from JPEG XL. libvips 8.16 and
  later still write an EXIF block of their own into JPEG XL, from the image's
  size, orientation and resolution, and fixed values; the image is upright and
  is given 72 dpi before the save, so the block holds nothing from the source.
  An image with an ICC profile is converted to sRGB before the JPEG XL save too,
  and a CMYK image with none is converted to sRGB, as libvips cannot save CMYK
  as JPEG XL. libvips' default effort, 7, is kept. JPEG XL is not yet the
  default output.
 - 2026-10-08 pixad runs on the Alpine release it is built on (closes #229): the
  runtime stage of the `Dockerfile` uses `alpine:3.22`, the release of the
  `golang:1.25.4-alpine3.22` image that the test phase and the build stage use,
  so all three have libvips 8.16, where the runtime image had 8.15.
 - 2026-10-08 requests no longer wait behind eviction queries that read a whole
  table (closes #227): the new `cache_usage` table holds the total cache usage,
  kept up to date by triggers on `source_content` and `variant_content` in the
  statement that adds, removes or resizes a row, and `UsageBytes` reads it. The
  reconciliation pass reads the content tables 1000 rows per query, sums them
  and corrects the total when it differs, unless a row changed while it summed.
  Source rows get `last_accessed_at` when added, so choosing source images to
  evict reads that column's index instead of sorting the whole table.
 - 2026-10-08 libvips' JPEG XL support is installed and required (part of #222):
  `script/bootstrap --cgo` installs `vips-jxl` when its package manager is apk,
  as Alpine's `vips` package lacks the support, and the runtime stage of the
  `Dockerfile` installs it too. `imgcache.NewService` fails, naming the fix,
  when `imageprocessor.CheckJPEGXLSupport` finds that libvips cannot load and
  save JPEG XL, so pixad does not start without it. A test saves an image as
  JPEG XL with govips and loads it back. JPEG XL is not yet a format pixa
  serves.
 - 2026-10-08 SQLite writes no longer fail with "database is locked" under load
  (closes #223): `internal/database` opens the database with one connection, so
  pixa's own reads and writes run on it one at a time instead of competing for
  SQLite's lock, where a write that kept losing could wait past the five-second
  busy timeout and be lost. The busy timeout stays, for another program writing
  to the same file. No code in pixa keeps rows or a transaction open while it
  runs another query, which with one connection would wait forever.
 - 2026-10-05 the format `auto` (closes #88): a format in the `/v1/image/` path,
  an encrypted URL's token and the generator page's format choice, chosen for
  each request from `Accept` once the signature or token is checked: AVIF when
  the header names `image/avif`, else WebP when it names `image/webp`, else JPEG
  when the first of `image/jpeg`, `image/*` and `*/*` that it names allows it,
  or when it names nothing; `q=0` refuses a format. AVIF and WebP must be named,
  as clients that cannot show them send the wildcards too. A header that allows
  none of the three answers 406, one that does not parse 400. The signature and
  the token cover `auto` itself; the cache key and `ETag` use the format chosen.
  Answers from the point the format is chosen carry `Vary: Accept`, next to the
  CORS `Vary: Origin`; fixed-format answers do not.
 - 2026-10-05 the markdown is formatted with prettier (closes #100): `script/fmt`
  and `script/fmt-check` run prettier 3.8.1, pinned in `package.json` and
  `yarn.lock`, on `**/*.md` after `gofmt`, with four-space tabs and
  `proseWrap: always` as `.prettierrc` says; `.prettierignore` keeps it off
  `REPO_POLICIES.md`, the copy from `sneak/prompts`, and `vendor/`. Plain
  `script/bootstrap` installs Node and Yarn as the one in `sneak/prompts` does
  and then prettier; `script/bootstrap --cgo` does not, as the `Dockerfile`
  stages that run it format nothing. The HTML templates stay unformatted:
  prettier cannot parse a Go template action inside a tag. The markdown was
  reflowed in a commit of its own.
 - 2026-10-05 lint and tests run as the `lint` and `test` phases of the
  `Dockerfile`, built with `--no-cache` (closes #202): `script/check`,
  `script/cibuild`, `script/docker`, `script/lint`, `script/test`,
  `script/setup` and `script/install-precommit` are now the copies from
  `sneak/prompts` `main`, unchanged. The `lint` phase runs golangci-lint from
  the image `REPO_POLICIES.md` names, with `libvips-dev` from `apt-get`; the
  `test` phase runs the tests with a 90-second timeout; the build stage depends
  on both. `Dockerfile.lint` and the `CHECK_EPOCH` build argument are gone, the
  formatting check runs on the host, and `make docker-versioned` and
  `make docker-test` call the scripts. `script/bootstrap`, `script/fmt`,
  `script/fmt-check`, `script/precommit` and `script/projectname` stay pixa's
  own. `script/bootstrap` installs git, make and Go, refreshing apt's package
  lists before its first apt install; with `--cgo`, which only the `test` phase
  and the build stage pass, it also installs the C compiler and the libvips and
  libheif libraries. The stage that compiles still takes the version from
  `git describe` when no `VERSION` is given, per
  https://git.eeqj.de/sneak/pixa/issues/166, so the copied scripts' comment that
  `.dockerignore` leaves out `.git` does not hold for pixa.
 - 2026-10-04 load test (closes #81): `script/loadtest [duration [clients]]`
  (`make loadtest`, defaults `10s` and `4`), a benchmark that `script/check`
  does not run, measures three scenarios, each against a new pixad container and
  a new upstream host, `cmd/loadtest-origin`: `hit` (one cached image), `miss`
  (a new source image every request) and `herd` (each new source image asked for
  by all clients at once). For each it prints vegeta's report (requests per
  second, latency percentiles, status codes), pixad's peak resident memory and
  the requests that reached the origin. `README.md` says how to run it and read
  it, and keeps 1-5k r/s as a target not yet measured. First measurement, with
  the defaults on a shared 48-CPU machine with other work running: a baseline
  for later changes, not a test of the target. `hit` 1413 r/s, p50 0.7 ms, p95
  8.7 ms, p99 44 ms, peak 53 MiB (4 clients that each wait for their answer, so
  not pixad's limit); `miss` 70 r/s, p50 52 ms, p95 91 ms, p99 122 ms, peak 100
  MiB, one fetch per request; `herd` 74 r/s, p50 52 ms, p95 69 ms, p99 111 ms,
  peak 60 MiB, 188 fetches for 749 requests.
 - 2026-10-04 the CI checkout fetches the tags (closes #208): the checkout step
  in `.gitea/workflows/check.yml` sets `fetch-depth: 0`, as `REPO_POLICIES.md`
  asks of a repo that takes its version from the tags, so a CI build of a tagged
  commit stamps the tag from `git describe` instead of a bare commit.
 - 2026-10-04 `config.yml` stays out of git and the Docker build context (closes
  #212): `.gitignore` now ignores `config.yml`, the config file Getting Started
  creates with the signing key, and `.dockerignore` leaves it out in every
  directory and in any letter case, as it already did `config.yaml` and
  `config.dev.yml`.
 - 2026-10-04 local config files stay out of the Docker build context (closes
  #211): `.dockerignore` now leaves out `config.yaml` and `config.dev.yml` in
  every directory and in any letter case, the local config files `.gitignore`
  keeps out of git because they can hold the signing key.
  `configs/config.example.yml` is still sent. `config.yml`, which Getting
  Started creates, is in neither file:
  https://git.eeqj.de/sneak/pixa/issues/212.
 - 2026-10-04 `cmd/pixad/main.go` is one call into `internal/` (closes #206):
  what it did (the command line and its `--config` flag, setting
  `PIXA_CONFIG_PATH`, ignoring `SIGPIPE`, starting the fx app) is now `Run` in
  `internal/app`, unchanged, and `main` calls it with `Version`, which the build
  still sets through `-X main.Version`. That code had no tests to move.
 - 2026-10-04 `.gitignore` ignores `.claude/` (closes #204): the entry and its
  comment are copied from the canonical `.gitignore` in `sneak/prompts`,
  unanchored so it matches at every depth. `.dockerignore` already has
  `.claude`.
 - 2026-10-04 `.dockerignore` keeps secrets out at every depth (closes #205): the
  file is now the standard one from `sneak/prompts`, whose patterns match in
  every directory and, for environment files and private keys, in any letter
  case, so a nested `.env` or `server.key` no longer reaches the build context.
  pixa still sends `.git` without `.git/config` in place of the standard file's
  `.git` line, and still leaves out `.gitignore`, `/bin` and `/data`.
 - 2026-10-04 `REPO_POLICIES.md` matches the canonical copy again (closes #196):
  it is replaced, unchanged, by `prompts/REPO_POLICIES.md` from `sneak/prompts`
  `main`. The rules it adds that pixa's tree breaks are filed:
  https://git.eeqj.de/sneak/pixa/issues/202 (lint and tests as `Dockerfile`
  phases built with `--no-cache`), https://git.eeqj.de/sneak/pixa/issues/203
  (the workflow's `script/docker-smoke` step),
  https://git.eeqj.de/sneak/pixa/issues/204 (`.claude/` in `.gitignore`),
  https://git.eeqj.de/sneak/pixa/issues/205 (`.dockerignore` patterns at every
  depth), https://git.eeqj.de/sneak/pixa/issues/206 (a thin `cmd/pixad/main.go`)
  and https://git.eeqj.de/sneak/pixa/issues/208 (`fetch-depth: 0` on the CI
  checkout, so the build sees the tags). Its rule that no build stage runs
  `git describe` is not followed: pixa takes the version from the `.git` in the
  build context, per https://git.eeqj.de/sneak/pixa/issues/166, as the copy on
  `sneak/prompts` `next` already says.
 - 2026-10-04 an integration test of the image proxy flow (closes #80):
  `TestImageProxyFlow` in `internal/server` starts the database, handlers and
  middleware from the constructors `pixad` uses, with a fresh state directory,
  and replaces only the upstream origin with a local test server. For a resize
  with a change to JPEG and for `orig`, the first request goes through the
  router, the real fetcher, libvips, the disk cache and SQLite and answers 200
  with the right content type and size and `X-Pixa-Cache: MISS`; the second
  answers `HIT` with the same image and the upstream has had one request; the
  source and the converted image are then in `cache/sources` and
  `cache/variants`, with their rows in `source_content`, `source_metadata` and
  `variant_content`. Two optional fields make this possible, which `pixad` does
  not set and the config file and environment cannot:
  `httpfetcher.Config.DialContext` connects in place of the dialer that refuses
  internal addresses, the URL and redirect checks still running, and
  `handlers.Params.Fetcher` replaces the fetcher the handlers build.
 - 2026-10-04 a URL made on the generator page with a `ttl` is tested to expire
  (closes #199): a new test in `internal/handlers` makes a URL on the generator
  page with a `ttl` of one second, checks that `/v1/e/` serves it at once, waits
  two seconds and checks that it then answers 410. The test waits for real, as
  pixa reads the clock directly when it makes and checks a URL; it waits two
  seconds because the time a URL expires is kept in whole seconds. Test only.
 - 2026-10-04 referer blocklist (closes #90): `referer_blocklist`
  (`PIXA_REFERER_BLOCKLIST`) lists hosts, written and matched as for
  `allowlist_hosts` with the same matcher; an entry of either list that is
  neither a host name (letters, digits, hyphens, underscores and dots, with at
  most one leading dot) nor an IP address, such as one with a port or a `*.`
  wildcard, aborts startup naming the setting and the entry. Both image routes
  refuse a request whose `Referer` names a listed host with 403 and a JSON error
  before the signature, the cache and the upstream fetch, so it fetches nothing
  and is refused whether or not the image is cached. A request with no
  `Referer`, or one that does not parse as a URL with a host, is served, so the
  list is easily got around; `README.md` and `configs/config.example.yml` say
  so. It does not apply to the login and generator pages.
 - 2026-10-04 fewer files in the repository root (closes #97):
  `config.example.yml` moved unchanged to `configs/config.example.yml`, and
  `README.md`, the comments in `internal/config/config.go` and the startup error
  for the placeholder signing key name the new path; `scripts/manual-test.sh`
  and its directory are deleted, as the handler tests in `internal/handlers`
  cover every check it made except two: fetching a real image from the internet,
  and a URL made on the generator page with a `ttl` answering 410 once the `ttl`
  has passed (https://git.eeqj.de/sneak/pixa/issues/199); `CONVENTIONS.md` is
  deleted, as `REPO_POLICIES.md` links the canonical Go HTTP server conventions.
 - 2026-10-04 SQLite writes no longer fail with "database is locked" (closes
  #198): pixa adds `_pragma=busy_timeout(5000)` to every `db_url`, so a write
  that finds another in progress on another connection waits up to five seconds
  for it, and the default `db_url` turns on WAL mode with
  `_pragma=journal_mode(WAL)`. The old default's `_journal_mode=WAL` is not a
  parameter the driver reads, so the database was never in WAL mode.
 - 2026-10-04 `TestPeriodicReconciliationAdoptsFileThatAppearsAfterStartup` only
  passes through a periodic pass (closes #189): it slept for three eviction
  intervals before writing its file, and a startup pass still running then could
  adopt the file itself. It now holds the test database's only connection until
  the startup pass waits for it after walking the empty variant directory,
  writes the file and lets the connection go, as
  `TestEvictionRunsOnPeriodicSchedule` does, so only a periodic reconciliation
  pass can adopt the file. Test only.
 - 2026-10-04 logging in, logging out, the URL generator and `/v1/e/` have
  handler tests (closes #77): new tests in `internal/handlers`, with no network,
  check that `GET /` without a login session shows the login form; a wrong key
  shows it again with an error and sets no session cookie; the right key answers
  303 to `/` with a session cookie marked `Secure`, `HttpOnly` and
  `SameSite=Strict`, with which `GET /` shows the generator page; `GET /logout`
  answers 303 to `/` with an empty session cookie sent with `Max-Age=0`;
  `POST /generate` without a login session answers 303 to `/`; `/v1/e/` serves
  the image for a valid token, answers 410 for an expired one and 400 for one
  with a character changed, cut short or made with another signing key; and a
  URL made on the generator page is served by `/v1/e/`. No code changes.
 - 2026-10-04 `TODO.md` merges with git's union merge (closes #190): a root
  `.gitattributes`, copied from `sneak/prompts`, marks it `merge=union`, so two
  branches that each add an entry at the top of Completed Steps merge without a
  conflict and keep both entries. Git now never reports a conflict in `TODO.md`:
  a real one keeps both versions of the lines, and two entries that share an
  identical line can end up one inside the other, which a rebase can do to an
  entry already on `next`. The Workflow above says to read the merged entries
  after every merge or rebase.
 - 2026-10-04 the default `cache_max_bytes` no longer shrinks as the cache fills
  (closes #184): for an omitted key, the cache works out the limit when it
  opens, after the database is open, as 75% of the sum of the free space on the
  filesystem containing `<state_dir>/cache/` and what the cache already holds by
  its own size accounting, at least 500 MiB, so a cache filled to its limit
  keeps that limit across a restart. The computation and its tests moved from
  `internal/config` to `internal/imgcache`; the config only records whether the
  key was set.
 - 2026-10-04 `TestEvictionRunsOnPeriodicSchedule` no longer races the evictor
  (closes #183): it wrote each variant file and then inserted its accounting row
  by hand, and a reconciliation pass between the two adopted the file first, so
  the insert failed. It now writes the files only, while holding the test
  database's only connection so the evictor's startup pass waits after walking
  the empty variant directory; a periodic reconciliation pass then adopts the
  files and the eviction pass after it evicts them. No other test in
  `internal/imgcache` inserts a row by hand after starting the evictor. Test
  only.
 - 2026-10-04 a config file pixa cannot read aborts startup (closes #176): of the
  places pixa looks for its config file on its own, only one where the file does
  not exist is passed over; any other error, such as a directory on the path
  that pixa may not enter, aborts startup naming the file, as a file that does
  not parse already did.
 - 2026-10-04 `.golangci.yml` re-vendored from the canonical copy (closes #57):
  the deprecated `gomodguard` is switched off, so lint runs print no deprecation
  warning; its successor `gomodguard_v2` runs with the shared module block list,
  and `depguard` keeps `net/http/httptest` out of files that are not tests. The
  tree needed no code changes.
 - 2026-10-04 the Content-Security-Policy allows no inline script or style
  (closes #125): `script-src` and `style-src` are `'self'` only. The generator
  page's two inline `onclick` handlers moved into
  `internal/static/generator.js`, attached with `addEventListener`; the bundled
  Tailwind script, which built styles in the browser, is replaced by a small
  hand-written `internal/static/style.css` with only the rules the login and
  generator pages use, the templates carrying a few plain class names in place
  of Tailwind's. No build step. The pages keep their layout, not every pixel of
  it.
 - 2026-10-04 deployment guide and example Caddy config (closes #89):
  "Deployment" in `README.md` says what the reverse proxy in front of pixa must
  do (terminate TLS; pass `Host`, `Origin` and `Referer` on unchanged; set
  `X-Forwarded-For`, with `trusted_proxies` to match; wait at least
  `downstream_timeout`; optionally refuse `/metrics`) and what pixa does itself,
  that the state directory needs a persistent volume and what `cache_max_bytes`
  counts, the health check for a load balancer, what a stop does and its exit
  codes, and what running outside Docker needs; `configs/Caddyfile` is the
  example, checked with `caddy validate`.
 - 2026-10-04 the metrics basic auth, CORS preflight, request logging and metrics
  recording have tests (closes #79): `MetricsAuth` on its own answers 401 with a
  challenge without credentials or with a wrong username or password and lets
  the configured ones through; a preflight request gets `*` for any origin when
  `access_control_allow_origin` is `*` and no `Access-Control-Allow-Origin` from
  another origin than the configured one; a `POST /` carrying the signing key
  leaves no trace of it in the request log line, and the login handler's own log
  lines leave out the submitted key; the metrics middleware on its own records a
  request it served, and the router records nothing while no metrics username is
  set. Not tested: that the router puts the basic auth in front of `/metrics`
  and records requests when a metrics username is set. Only one test per package
  can set up `/metrics`, and in `internal/server` that is
  `TestMaintenanceModeKeepsOtherRoutes`, which needs the owner's approval to
  change; #180 holds it. Tests only; the basic auth library already compares the
  password in constant time.
 - 2026-10-04 the image route's signature check and error answers are tested
  (closes #76): new tests in `internal/handlers`, with no network, check the
  status and JSON error body for a missing, wrong, unpadded, upper-case or
  expired signature on a host not on the allowlist, or a valid one sent for its
  parent domain, a sibling host, a subdomain or the host with another domain
  appended (401), an unparseable path (400), `localhost` as the upstream host
  (403) and an upstream error (502); that an allowlisted host is served without
  a signature, another host only with a valid one; and the answers of
  `/robots.txt` and the health check. No code changes.
 - 2026-10-04 request IDs returned and passed on, and `/v1/e/` revalidates
  (closes #84): pixa's own `RequestID` middleware, in place of chi's, gives each
  request an ID, its own `X-Request-ID` when that is at most 64 letters, digits,
  `-`, `_` or `.` and a random one otherwise, stores it where chi's did and
  sends it back as `X-Request-ID` on every response; the upstream fetch sends
  that ID, and the "upstream fetched", "image converted" and "image served" log
  lines carry it as `request_id`, a fetch shared by several requests carrying
  the first request's; `/v1/e/` sets `ETag`, answers a matching `If-None-Match`
  with 304 and is routed for `HEAD`, the `ETag` and 304 code being
  `notModified`, which `/v1/image/` calls too; its token checks moved unchanged
  into `parseImageEncRequest` to keep `HandleImageEnc` within the line limit; no
  `Vary` is added, as no response depends on a request header except the image
  routes' CORS headers, for which `go-chi/cors` already sends `Vary: Origin`;
  `Vary: Accept` is left to #88.
 - 2026-10-04 routes, encrypted URLs and config file documented (closes #75):
  "Routes" in `README.md` lists every route with its method, purpose, what it
  needs and the status codes it answers with, and says `q` and `fit` are part of
  what is cached; "Encrypted URLs" covers logging in, making one on the
  generator page, how long it lasts and the 410 once it has expired;
  "Configuration" gives the order in which pixa looks for its config file;
  `config.example.yml` lists `db_url` and `env` and gives every key's default;
  `scripts/manual-test.sh` is left to #97.
 - 2026-10-04 shutdown stops cache eviction in progress (closes #102):
  `StartEviction` runs the eviction goroutine with its own context, which
  `StopEviction` cancels, so a pass in progress stops at its next database call,
  file, row or eviction candidate instead of running to completion, and no pass
  starts after it, so a stop logs at most one warning; `StopEviction` takes a
  context and, when that context ends before the goroutine exits, stops waiting
  and returns its error; the handlers' stop hook passes fx's stop context, so an
  eviction still running when fx's stop deadline ends fails the stop and makes
  the exit code 1.
 - 2026-10-04 dead code in `internal/imgcache` is gone (closes #73): `Purge`,
  which only returned an error and which nothing called, is no longer part of
  the `ImageCache` interface or `Service`; the `SignatureValidator`, `Allowlist`
  and `Storage` interfaces, which nothing implemented or used, are deleted.
  Nothing else changes.
 - 2026-10-04 upstream host semaphores and variant `.meta` files no longer
  outlive their use (closes #87): the fetcher counts the fetches holding or
  waiting for a slot of each upstream host's semaphore and removes the host's
  semaphore once none is left, so fetches from many hosts no longer leave one
  semaphore each until restart; `VariantStorage.Delete` removes the variant's
  `.meta` file along with it, a missing `.meta` file not being an error, and
  `DeleteWithMeta`, which eviction called for that, is gone.
 - 2026-10-04 `README.md` matches the code (closes #74): "Storage" names the
  cache directories pixa uses (`cache/sources`, `cache/metadata`,
  `cache/variants`) and how files are named in each, and the comments in
  `001_schema.sql` name the same paths; the routes and the signature section
  list the same output formats, `jpg` and `original` included; the TLS sentence
  names `allow_http` as its exception; "Metrics" says only generic HTTP and Go
  runtime metrics exist, measured and served only when the metrics username and
  password are set.
 - 2026-10-03 shutdown sets the exit code and waits for image processing (closes
  #86): fx alone handles SIGINT and SIGTERM, and the server's own signal handler
  is gone; fx's `Run` in `cmd/pixad` exits with the shutdown's code: 0 for a
  signal, 1 when the HTTP server cannot listen or the app fails to start or to
  stop; the server's stop hook, which fx waits for, stops the HTTP server, waits
  for the images still being processed, both within 5 seconds, then flushes
  Sentry; images still being processed after that are logged with their count
  and make the exit code 1; a Sentry DSN that cannot be used fails startup, so
  the stop hooks of what had already started run, instead of exiting the process
  from a goroutine; the eviction loop is left to #102.
 - 2026-10-03 every `script/cibuild` and `script/docker` run executes the checks
  (closes #101): the `Dockerfile` declares `CHECK_EPOCH` above `make fmt-check`
  and `make lint` in the lint stage and above `make test` in the build stage,
  and each of those steps names it in its command; both scripts pass a new value
  on every run, so Docker runs the checks instead of reusing cached results,
  while the `script/bootstrap` steps stay cached; a plain `docker build .` still
  works, leaves it empty, and reuses the check steps only for an identical build
  context; the `script/cibuild` comment and `README.md` no longer say that any
  successful build implies a green repo.
 - 2026-09-29 share concurrent misses (closes #65): requests that miss the same
  variant at once (the same cache key, so quality and fit included) share one
  upstream fetch or cached source read and one transcode through
  `golang.org/x/sync/singleflight`; the first request's processing ignores its
  cancellation but keeps its deadline, and the others wait for its image or
  error holding no upstream connection or processing slot, and stop waiting when
  their own context ends; the request doing the processing waits for it even
  then, until it ends, which can be after its deadline; a request whose context
  has already ended starts nothing; each request counts one miss, and the
  processing counts its fetch and transcode once; a panic while processing is
  reported to Sentry when `sentry_dsn` is set and becomes an error for every
  waiting request instead of stopping pixad; documented in `README.md`.
 - 2026-09-29 only the image routes send CORS headers (closes #98): the CORS
  middleware, with the `access_control_allow_origin` origin, moved from the
  router root onto a `/v1` subrouter holding `/v1/image/` and `/v1/e/`, where it
  still answers a preflight `OPTIONS` request; the login and URL generator
  pages, `/metrics` and the other routes send no `Access-Control-Allow-Origin`;
  documented in `README.md` and `config.example.yml`.
 - 2026-10-02 a plain `docker build .` stamps the tag or short commit, not `dev`
  (closes #166): `.dockerignore` lets `.git` into the build context, without
  `.git/config`; with no `VERSION` build argument the `Dockerfile` takes the
  version from `git describe --tags --always`, and fails the build if the
  context carries `.git` and no version comes out; `ARG VERSION` has no default;
  pixad logs its version, with its name and architecture, as its first log line
  at startup.
 - 2026-09-29 the container makes `/var/lib/pixa` usable by itself (closes #159):
  `deploy/docker-entrypoint.sh` creates the directory if it is missing, gives
  the directory and everything in it to `pixad` when the directory or one of its
  top-level entries belongs to another user or group, sets its mode to `750`,
  then runs the server as `pixad`; data left by an earlier run under another uid
  is taken over this way; "Running under upaas" in `README.md` no longer tells
  the operator to create or chown the host directory.
 - 2026-09-29 variant content types kept in memory (closes #70):
  `Cache.metaCache` holds the content types of up to 10,000 variants in an LRU
  (`github.com/hashicorp/golang-lru/v2`), filled by `StoreVariant` and by
  `GetVariant` after it reads a `.meta` file, where a type `StoreVariant` added
  meanwhile is kept over the one read, and never with the
  `application/octet-stream` served for a variant without one; for a variant it
  holds, `GetVariant` skips the `.meta` read, still opening the variant file and
  taking the size from it; eviction removes the entry before deleting the files,
  and `GetVariant` removes it when the file will not open; the cap is a
  constant, not a setting; the unused `variantMeta` type is gone; `README.md`
  describes it.
 - 2026-09-29 maintenance mode refuses image requests (closes #71): while
  `maintenance_mode` is on, `/v1/image/` and `/v1/e/` answer 503 with a
  `Retry-After` header and the JSON error body, from one middleware in
  `internal/server/routes.go`; the health check stays 200 and reports
  `maintenance_mode`, as the image's Docker `HEALTHCHECK` requests it and upaas
  marks a deploy failed when its container is unhealthy; the login and URL
  generator pages and `/metrics` keep working; documented in `README.md` and
  `config.example.yml`.
 - 2026-09-29 bound concurrent image processing and upstream fetches (closes
  #64): `max_concurrent_processing` (default the number of CPUs pixa can use)
  limits the images decoded and encoded at once, and `upstream_connections`
  (default 64) the connections to all upstream hosts together, on top of
  `upstream_connections_per_host`; a fetch holds its connection until its image
  has been processed, and a request whose source is cached reads it only once it
  has a processing slot; a request that finds either limit reached waits up to
  10 seconds for a free one, then gets 503 `server busy, try again later`;
  libvips runs one worker thread per image with its operation cache off;
  documented in `README.md` and `config.example.yml`.
 - 2026-09-29 Dockerfiles install through `script/bootstrap` (closes #95): the
  `Dockerfile` lint and build stages and `Dockerfile.lint` copy `script/`,
  `go.mod` and `go.sum`, then run `script/bootstrap` in place of their own
  `apk add` lines, so the build dependencies are listed in one place;
  `script/bootstrap` now also installs a C compiler when `gcc` is missing; the
  build uses `-trimpath` and `-s -w` and keeps `CGO_ENABLED=1` for govips;
  `ARG VERSION` sits just above the build, so a new version reruns neither
  `script/bootstrap` nor the tests.
 - 2026-09-29 migrations at the path `REPO_POLICIES.md` sets (closes #96): the
  migration files moved, contents unchanged, from `internal/database/schema/` to
  `internal/db/migrations/` as `000_migration.sql` and `001_schema.sql`; the
  `internal/db/migrations` package embeds them and `internal/database` reads
  them through its `FS()`; the `internal/database` package itself stays; the
  version still comes from the filename prefix, so a database that has recorded
  versions 0 and 1 runs neither again.
 - 2026-09-29 `trusted_proxies` advice and signature padding in `README.md`
  (closes #150): the login-limit paragraph, the `trusted_proxies` entry and
  `config.example.yml` say to set `trusted_proxies` to the address pixa sees for
  requests that come through the proxy, which the request log shows as
  `remoteIP` while it is not trusted; for a proxy on the Docker host that
  connects over `127.0.0.1` that is the Docker network's gateway, not the
  proxy's own address; the signature section says `sig` is base64url with the
  `=` padding kept, and gives the example's `sig` for a stated signing key.
 - 2026-09-29 fixed uid and gid for `pixad` (closes #151): the image creates the
  `pixad` group with gid 65532 and the `pixad` user with uid 65532, instead of
  the first free uid 1000, so a bind-mounted `/var/lib/pixa` given to `pixad` is
  not owned on the host by a person's login account; the first-run step of
  "Running under upaas" in `README.md` names the uid and gid.
 - 2026-09-29 `max-age` never outlives an expiring URL (closes #63): both image
  routes build `Cache-Control` from the request's `Expires`, which an encrypted
  URL's expiry now fills too; `max-age` is one year, or the whole seconds left
  until the `exp` of a `/v1/image/` URL or the expiry of an encrypted URL when
  that is sooner, never negative; an allowlisted host's URL that has an `exp`
  follows it too; `immutable` stays, as freshness now ends at the expiry;
  documented in `README.md`.
 - 2026-09-28 add the four settings `README.md` documented but pixa did not have,
  which aborted startup as unknown keys (closes #61):
  `access_control_allow_origin` (default `*`, the CORS origin),
  `upstream_fetch_timeout` (default `30s`), `upstream_max_response_size`
  (default 50 MiB) and `downstream_timeout` (default `60s`, both the server's
  write timeout and the per-request timeout); each has a `PIXA_` variable;
  durations are positive Go duration strings, the size a whole number of bytes
  up to 1 GiB, the origin `*` or one `http` or `https` origin as `README.md`
  describes it; an invalid value aborts startup naming the key and the value;
  documented in `config.example.yml` and `README.md`.
 - 2026-09-28 cache stats report real numbers (closes #56): `Cache.Stats` counts
  the cached source images and processed variants (`source_content` plus
  `variant_content`) and takes their size from `Cache.UsageBytes`, instead of
  reading `request_cache` and `output_content`, which nothing writes; those two
  tables are left in the schema; a disabled disk cache reports no items and no
  size. A hit is counted even when the request context has ended. A miss is
  counted after it is served or fails, also when the request context has ended
  by then, with the bytes it read from upstream, so `upstream_fetch_count` and
  `upstream_fetch_bytes` move, including for an upstream body that fails partway
  or a fetched source that then fails the magic byte check; `transform_count`
  counts each image the image processor transcodes.
 - 2026-09-28 strip metadata from processed images (closes #82): every output is
  exported with govips' `StripMetadata`, so it carries no EXIF, XMP, IPTC or ICC
  profile; the image is first turned upright with `AutoRotate` (before sizes are
  worked out) and, when it has an ICC profile, converted to sRGB; the `orig`
  format is re-encoded and stripped like any other, as pixa never serves the
  source bytes; there is no setting to keep metadata; documented in `README.md`.
 - 2026-09-28 rate limit the login form (closes #66): `POST /` is limited to 5
  attempts per minute per client address, and an attempt over the limit is
  refused with 429 and a `Retry-After` header; the address is the one
  `internal/clientip` resolves through `trusted_proxies`, an IPv6 client is
  counted by its /64, and an IPv4-mapped address as the IPv4 address it carries;
  the limit is a `RateLimit` middleware in `internal/middleware` on
  `github.com/go-chi/httprate`, which the image routes can reuse; the library
  keeps counts for the current and the previous minute only; documented in
  `README.md`.
 - 2026-09-28 refuse an unparseable `exp` on `/v1/image/` and log swallowed cache
  errors (closes #72): an `exp` in the URL that is not a whole number, an empty
  `exp=` included, is a 400 naming `exp` and the value, instead of being ignored
  and answered with 401 as if the URL had no `exp`; only an `exp` missing from
  the URL is unchanged; `README.md` says so where it documents `exp`. A failed
  variant `.meta` write, source metadata JSON write, `Stats` count query, stats
  counter update, negative cache write or expired negative cache delete is now
  logged at `warn` with the path or key and the error, and stays non-fatal.
 - 2026-09-28 refuse an empty `fit` on `/v1/image/` (closes #139): a `fit` in the
  URL with an empty value (`fit=`) is a 400 naming `fit`, instead of being
  served as `cover` and verified against a signature made for `cover`; only a
  `fit` missing from the URL is still `cover`; any other value still goes
  through the existing fit-mode check; `README.md` says so where it documents
  `fit`.
 - 2026-09-28 refuse an invalid `q` on `/v1/image/` (closes #134): a `q` that is
  not a whole number from 1 to 100, an empty `q` included, is a 400 naming `q`
  and the value, instead of being served at the default 85; the route reads `q`
  with the generator's quality check (`parseFormInt` with `minQuality` and
  `maxQuality`); only a `q` missing from the URL is still 85; a query string
  that cannot be decoded, such as `q=80%`, is a 400 showing it; any query
  parameter given more than once (`q`, `fit`, `sig`, `exp` alike) is a 400
  naming it, so none is read from its first value only; `README.md` states the
  range and both query-string rules.
 - 2026-09-28 unknown `PIXA_` environment variables abort startup (closes #133):
  a variable whose name starts with `PIXA_` but is neither a setting's variable
  nor `PIXA_CONFIG_PATH` aborts startup naming it, as an unknown config key
  does, and `PIXA_PORT` is named with a pointer to `PORT`; the check runs after
  the config file loads, so the variables the file's `env:` section sets are
  checked too; documented in `README.md`.
 - 2026-09-28 start on a fresh upaas volume (closes #129): the image starts as
  root only to give `/var/lib/pixa` to `pixad` when `pixad` does not own it
  (`deploy/docker-entrypoint.sh`), then runs the server as `pixad` through
  `su-exec`, so a root-owned host directory bind-mounted there no longer stops
  the container at startup; `README.md` gains a "Running under upaas" section.
 - 2026-09-28 run all linting in Docker via `Dockerfile.lint` + `script/lint`
  (closes #104): `make lint` calls `script/lint`, the only way the linter is
  run; inside a container (both Dockerfiles set `container=docker`) it runs
  `golangci-lint`, anywhere else it builds the hash-pinned `Dockerfile.lint`,
  whose last step runs `script/lint` again; the `Dockerfile` lint stage runs
  `make lint`; no host or nix-shell `golangci-lint` path remains
  (`script/bootstrap` installs no linter); a per-run `CACHEBUST` build-arg keeps
  the lint step from being served from cache, and a tmpfs mount on that step
  keeps Go's and golangci-lint's caches out of its layer, so a run leaves no
  large build cache behind; `golangci-lint config verify` stays out, as it
  fetches its schema over an unpinned live HTTPS call
 - 2026-09-28 every setting as an environment variable (closes #128, also covers
  #99): each config key can be set by `PIXA_` plus the key in upper case (`.`
  written as `_`), and the port by `PORT`; a variable present in the
  environment, even empty, wins over the config file, which wins over the
  default; the typed getters read the variable first, so every existing check
  applies to it and a bad value aborts startup naming the variable; lists are
  comma-separated, and an empty variable (or `""` in the file) is an empty list;
  the Docker image no longer bakes in `config.docker.yml` or passes `--config`,
  and its `HEALTHCHECK` probes `PORT` (default `8080`); the config file is
  looked for under `/etc/pixa` and `~/.config/pixa` instead of the daemon name
  `pixad`; documented in `README.md` and `config.example.yml`.
 - 2026-09-28 quality and fit in the URL signature (closes #60): the signed data
  is now `host:path:query:width:height:format:expiration:quality:fit`, using
  `85` and `cover` when the URL has no `q` or `fit`, so one signed URL can no
  longer be replayed across other quality and fit values to create unauthorized
  cache entries and transcodes; the known-answer vectors in
  `internal/signature/golden_test.go` and the README signature specification
  describe the new format.
 - 2026-09-28 Docker image healthcheck (closes #111): a `HEALTHCHECK` in the
  runtime stage probing `/.well-known/healthcheck.json` with busybox `wget`;
  `script/docker-smoke` (`make docker-smoke`) builds the image, starts it with a
  throwaway `PIXA_SIGNING_KEY`, and passes only once Docker reports it healthy
  within 30 seconds, removing the container on exit; the Gitea workflow runs it
  after `script/cibuild`.
 - 2026-09-21 trusted-proxy client IP resolution (closes #94): a
  `trusted_proxies` config key taking a list of CIDRs, parsed by the same
  `net/netip` list parser as `blocked_networks` (an invalid entry aborts startup
  naming the key and value; an omitted key defaults to the RFC 1918 private
  ranges, an explicitly empty list trusts no one, and an explicit list replaces
  the default); a new `internal/clientip` package resolves the client address by
  honoring `X-Forwarded-For` only when the direct peer is a trusted proxy,
  walking the chain right-to-left to the rightmost non-proxy entry, so a client
  connecting directly cannot spoof its address; the resolved address is stored
  in the request context by a new middleware and used by the request-logging
  middleware and the login-attempt logs in place of the raw peer address;
  documented in `README.md` and `config.example.yml`.
 - 2026-09-21 blocked networks configuration extending SSRF protection: a
  `blocked_networks` config key taking a list of CIDRs (parsed with `net/netip`,
  an invalid entry aborts startup naming the key and value), added to the
  built-in blocklist rather than replacing it; the built-in ranges extended to
  CGNAT `100.64.0.0/10`, IETF protocol assignments `192.0.0.0/24`, benchmark
  `198.18.0.0/15`, and NAT64 `64:ff9b::/96` (IPv4-mapped forms covered);
  enforcement stays in the dial-time re-resolution so the DNS-rebinding window
  remains closed; documented in `README.md` and `config.example.yml`.
 - 2026-09-21 validate dimensions and fit mode on the encrypted-URL route and the
  token generator (closes #62): `imgcache.ValidateDimension` alone holds the
  `MaxDimension` bound and is used by the path parser, by the new
  `ValidateImageRequest` (which also applies `ValidateFitMode`) and by the
  generator; both the `/v1/image/` and `/v1/e/` routes call
  `ValidateImageRequest`, so an over-limit size or an unknown fit mode is a 400
  rather than an out-of-memory or a 500 from the processor; the URL generator
  answers 400 naming the field for a `width` or `height` that is not a number or
  fails the shared check, a `quality` that is not a number from 1 to 100, a
  `ttl` that is not a number from 0 to the largest number of seconds the expiry
  calculation can hold, or an unknown `fit`; an empty `quality` is 85 and an
  empty `ttl` never expires; the form's width and height inputs stop at 8192
 - 2026-09-21 http.Server hardening (closes #92): added `HTTPReadHeaderTimeout`
  (10s, bounds the slowloris header dribble) and `HTTPIdleTimeout` (120s, bounds
  keep-alive reuse) alongside the existing timeouts and wired them onto the
  server; added a `LimitBody` middleware capping the two form POST bodies
  (`POST /`, `POST /generate`) at `MaxFormBytes` (1 MiB) and returning 413,
  applied ahead of the CSRF middleware so an oversized body is refused as 413
  rather than being read as a missing CSRF token (403); left `WriteTimeout` at
  60s unchanged
 - 2026-08-07 update golangci-lint to v2.12.2 with the canonical `.golangci.yml`
  (v2 schema, `default: all` minus six disabled linters, `lll` 88, tests
  included): bumped the pinned `golangci/golangci-lint:v2.12.2-alpine` image in
  `Dockerfile` and the release-archive sha256 pins in `script/bootstrap`; fixed
  the findings the stricter config surfaced (notably `paralleltest`, `wsl_v5`,
  `goconst`, `lll`, `noinlineerr`, `err113`, `errcheck`, `testpackage` —
  white-box test files renamed to `*_internal_test.go`), including #55's code
  absorbed after it merged, iterating the pinned linter to `0 issues.`; no
  single finding total is substantiable, since golangci-lint's `uniq-by-line`
  reveals new findings on a line as others there are fixed — the documented
  re-measurements were 81 after the #53 merge and 149 after the #55 merge; three
  behavior changes, so not a pure no-op: `Cache.StoreVariant` now takes a
  `context.Context` (`noctx`), so a cancelled request skips its best-effort
  accounting row; `MetadataStorage.Store`'s cleanup defer was dead on `main` and
  leaked `.tmp-*.json` on failure, now fixed with explicit removals; and the
  `signing_key` validation error text gained `value too short: `; the eviction
  loop's uncancellable context is deferred to #102 under a
  `//nolint:contextcheck`; three `//nolint:tagliatelle` directives keep the
  snake_case JSON wire/disk formats unchanged; `make check` green
 - 2026-08-07 implement cache size management and eviction (closes #51): new
  `cache_max_bytes` config key validated by the startup framework (explicit
  values used exactly with no floor, `0` disables the disk cache entirely,
  omitted defaults to max(75% of free space on the filesystem containing
  `<state_dir>/cache/`, 500 MiB), logged at startup); processed variants are now
  tracked in the database (a new `variant_content` table and an LRU timestamp on
  `source_content`) so total usage is two SUMs, never a directory scan on the
  hot path; a background goroutine evicts globally least-recently-used entries
  (variants and source blobs merged) to the limit, woken by a periodic ticker
  and by write-pressure notifications from stores; a source blob and ALL of its
  `source_metadata` references are deleted in one transaction before the file is
  unlinked, so multi-referenced blobs are never removed while referenced and
  rows never point at deleted files; a startup and periodic reconciliation pass
  adopts untracked variant files, drops rows for missing files, removes
  unreachable source blobs, and sweeps stale temp files
 - 2026-08-07 validate configuration on startup, fail fast on bad config (closes
  #52): a config value that is set but unparseable or invalid aborts startup
  naming the key and value (defaults apply only to omitted keys), unknown config
  keys abort startup, a malformed config file aborts instead of being skipped,
  and `state_dir` is verified creatable and writable before the listener binds
 - 2026-08-07 manual test pass of the auth and encrypted URL flows against a
  locally built and running `pixad` (built from `main` at `6573b9d`, port 18099,
  local throwaway config); all six checks passed, plus all nine tests in
  `scripts/manual-test.sh` (closes #49):
    - [x] visit `/` and see the login form: HTTP 200, `Pixa - Login` page with
          `name="key"` password form
    - [x] wrong key shows an error: POST `/` with `key=wrong-key` returned HTTP
          200 login page containing "Invalid signing key"
    - [x] correct signing key shows the generator form: POST `/` returned HTTP
          303 to `/` with
          `Set-Cookie: pixa_session=...; HttpOnly; Secure; SameSite=Strict`; GET
          `/` with that cookie rendered `Pixa - URL Generator` with the
          `/generate` form and logout link
    - [x] a generated encrypted URL serves the image: POST `/generate`
          (ttl=3600) produced a `/v1/e/<token>/img.jpeg` URL that returned HTTP
          200, `Content-Type: image/jpeg`, an 800x600 baseline JPEG of 61706
          bytes
    - [x] an expired URL (short TTL) returns 410: a ttl=1 URL fetched after 3 s
          returned HTTP 410 Gone with
          `{"error":"URL has expired","status":410,...}`
    - [x] logout redirects back to login: GET `/logout` returned HTTP 303 to `/`
          with `Set-Cookie: pixa_session=; Max-Age=0`; subsequent GET `/`
          rendered the login form again
 - 2026-08-07 fix the two remaining gosec findings (G124 in internal/session):
  session cookies now always carry Secure/HttpOnly/SameSite=Strict on both the
  set and clear paths; `make check` green (closes #47)
 - 2026-07-07 Adopted scripts-to-rule-them-all: `script/` entrypoints, Makefile
  shims, README Entrypoints section
 - 2026-04-07 extract magic byte detection into internal/magic (#42)
 - 2026-03-25 extract allowlist package from internal/imgcache (#41)
 - 2026-03-25 move schema_migrations table creation into 000.sql (#36)
 - 2026-03-20 enforce and document exact-match-only signature verification (#40)
 - 2026-03-20 bound imageprocessor.Process input read to prevent unbounded memory
  use (#37); consolidate appname into an internal/globals constant (#34)
 - 2026-03-18 parse version prefix from migration filenames (#33)
 - 2026-03-15 QA audit fixes for 1.0/MVP readiness (#25)
 - 2026-03-02 split Dockerfile with pre-built golangci-lint stage for faster CI
  (#23)
 - 2026-02-25 repo policy compliance: CI workflow, hash-pinned images,
  golangci-lint and gosec fixes of that date (#14); arm64 Docker build fix (#16)
 - 2026-01-08 WebP and AVIF encoding support via govips (both former P0 image
  processing items, now done)
 # Future Steps
 - P2: HTTP response handling
    - Last-Modified headers
 - P2: configuration
    - YAML config file support
 - P2: operational
    - optional Sentry error reporting
    - comprehensive request logging
    - Prometheus performance metrics
    - measure the 1k to 5k req/s target with `script/loadtest` on a machine not
      shared with other work
@@ -1,21 +1,10 @@
-// Package main is the entry point for the pixad image proxy server. pixad
+// Package main is the entry point for the pixad image proxy server.
 // also runs as a child process of itself, to read the size of an SVG source
 // or to render it (see imageprocessor.RunAsSVGChildProcess).
 package main
-import (
+import "sneak.berlin/go/pixa/internal/app"
 	"os"
 	"sneak.berlin/go/pixa/internal/app"
 	"sneak.berlin/go/pixa/internal/imageprocessor"
 )
 var Version string //nolint:gochecknoglobals // set by ldflags
 func main() {
 	if imageprocessor.IsSVGChildProcess(os.Args[1:]) {
 		os.Exit(imageprocessor.RunAsSVGChildProcess(os.Args[1:]))
 	}
 	app.Run(Version)
 }
@@ -108,11 +108,10 @@ upstream_connections_per_host: 20
 # downstream_timeout has ended first.
 upstream_connections: 64
-# Maximum number of images decoded and encoded at once (default: half the
+# Maximum number of images decoded and encoded at once (default: the
-# number of CPUs pixa can use, at least 1; the number of CPUs follows a
+# number of CPUs pixa can use, which follows a container's CPU limit). A
-# container's CPU limit). A request that finds none free waits up to 10
+# request that finds none free waits up to 10 seconds for one, and if none
-# seconds for one, and if none frees up it is answered 503, unless
+# frees up it is answered 503, unless downstream_timeout has ended first.
 # downstream_timeout has ended first.
 # max_concurrent_processing: 4
 # How many requests to the image routes (/v1/image/ and /v1/e/) one client
@@ -158,9 +157,8 @@ access_control_allow_origin: "*"
 # Sentry DSN for error reporting (default: empty, which turns it off)
 sentry_dsn: ""
-# Username and password for /metrics, set together (default: unset). pixa
+# Username and password for /metrics, set together (default: unset). Metrics
-# serves /metrics, and measures HTTP requests, only when both are set. It
+# are measured and /metrics is served only when both are set.
 # measures the pixa_ metrics either way.
 # metrics:
 #   username: "admin"
 #   password: "secret"
@@ -14,10 +14,10 @@ require (
 	github.com/go-chi/httprate v0.16.0
 	github.com/gorilla/csrf v1.7.3
 	github.com/gorilla/securecookie v1.1.2
 	github.com/hashicorp/golang-lru/v2 v2.0.7
 	github.com/prometheus/client_golang v1.23.2
 	github.com/slok/go-http-metrics v0.13.0
 	github.com/spf13/cobra v1.10.2
 	go.uber.org/dig v1.19.0
 	go.uber.org/fx v1.24.0
 	golang.org/x/crypto v0.41.0
 	golang.org/x/sync v0.19.0
@@ -127,6 +127,7 @@ require (
 	go.opentelemetry.io/otel v1.36.0 // indirect
 	go.opentelemetry.io/otel/metric v1.36.0 // indirect
 	go.opentelemetry.io/otel/trace v1.36.0 // indirect
 	go.uber.org/dig v1.19.0 // indirect
 	go.uber.org/multierr v1.11.0 // indirect
 	go.uber.org/zap v1.27.0 // indirect
 	go.yaml.in/yaml/v2 v2.4.2 // indirect
@@ -228,6 +228,8 @@ github.com/hashicorp/go-version v1.2.1/go.mod h1:fltr4n8CU8Ke44wwGCBoEymUuxUHl09
 github.com/hashicorp/golang-lru v0.5.0/go.mod h1:/m3WP610KZHVQ1SGc6re/UDhFvYD7pJ4Ao+sR/qLZy8=
 github.com/hashicorp/golang-lru v0.5.4 h1:YDjusn29QI/Das2iO9M0BHnIbxPeyuCHsjMW+lJfyTc=
 github.com/hashicorp/golang-lru v0.5.4/go.mod h1:iADmTwqILo4mZ8BN3D2Q6+9jd8WM5uGBxy+E8yxSoD4=
 github.com/hashicorp/golang-lru/v2 v2.0.7 h1:a+bsQ5rvGLjzHuww6tVxozPZFVghXaHOwFs4luLUK2k=
 github.com/hashicorp/golang-lru/v2 v2.0.7/go.mod h1:QeFd9opnmA6QUJc5vARoKUSoFhyfM2/ZepoAG6RGpeM=
 github.com/hashicorp/hcl v1.0.1-vault-7 h1:ag5OxFVy3QYTFTJODRzTKVZ6xvdfLLCA1cy/Y6xGI0I=
 github.com/hashicorp/hcl v1.0.1-vault-7/go.mod h1:XYhtn6ijBSAj6n4YqAaf7RBPS4I06AItNorpy+MoQNM=
 github.com/hashicorp/logutils v1.0.0/go.mod h1:QIAnNjmIWmVIIkWDTG1z5v++HQmx9WQRO+LraFDTW64=
@@ -72,3 +72,13 @@ func (w *HostAllowList) IsAllowed(u *url.URL) bool {
 	return false
 }
 // IsEmpty returns true if the allow list has no entries.
 func (w *HostAllowList) IsEmpty() bool {
 	return len(w.exactHosts) == 0 && len(w.suffixHosts) == 0
 }
 // Count returns the total number of allow list entries.
 func (w *HostAllowList) Count() int {
 	return len(w.exactHosts) + len(w.suffixHosts)
 }
@@ -139,3 +139,87 @@ func TestHostAllowList_IsAllowed_SuffixMatch(t *testing.T) {
 		},
 	})
 }
 func TestHostAllowList_IsEmpty(t *testing.T) {
 	t.Parallel()
 	tests := []struct {
 		name     string
 		patterns []string
 		want     bool
 	}{
 		{
 			name:     "empty",
 			patterns: []string{},
 			want:     true,
 		},
 		{
 			name:     "nil",
 			patterns: nil,
 			want:     true,
 		},
 		{
 			name:     "whitespace only",
 			patterns: []string{"  ", ""},
 			want:     true,
 		},
 		{
 			name:     "has entries",
 			patterns: []string{"example.com"},
 			want:     false,
 		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			w := allowlist.New(tt.patterns)
 			if got := w.IsEmpty(); got != tt.want {
 				t.Errorf("IsEmpty() = %v, want %v", got, tt.want)
 			}
 		})
 	}
 }
 func TestHostAllowList_Count(t *testing.T) {
 	t.Parallel()
 	tests := []struct {
 		name     string
 		patterns []string
 		want     int
 	}{
 		{
 			name:     "empty",
 			patterns: []string{},
 			want:     0,
 		},
 		{
 			name:     "exact hosts only",
 			patterns: []string{"a.com", "b.com", "c.com"},
 			want:     3,
 		},
 		{
 			name:     "suffix hosts only",
 			patterns: []string{".a.com", ".b.com"},
 			want:     2,
 		},
 		{
 			name:     "mixed",
 			patterns: []string{"exact.com", ".suffix.com"},
 			want:     2,
 		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			w := allowlist.New(tt.patterns)
 			if got := w.Count(); got != tt.want {
 				t.Errorf("Count() = %v, want %v", got, tt.want)
 			}
 		})
 	}
 }
@@ -2,16 +2,12 @@
 package app
 import (
 	"context"
 	"fmt"
 	"io"
 	"os"
 	"os/signal"
 	"syscall"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/spf13/cobra"
 	"go.uber.org/dig"
 	"go.uber.org/fx"
 	"sneak.berlin/go/pixa/internal/config"
 	"sneak.berlin/go/pixa/internal/database"
@@ -20,7 +16,6 @@ import (
 	"sneak.berlin/go/pixa/internal/healthcheck"
 	"sneak.berlin/go/pixa/internal/logger"
 	"sneak.berlin/go/pixa/internal/middleware"
 	"sneak.berlin/go/pixa/internal/providers"
 	"sneak.berlin/go/pixa/internal/server"
 )
@@ -56,10 +51,7 @@ func run(_ *cobra.Command, _ []string) {
 	// A write to a closed stdout or stderr must not end the process.
 	signal.Ignore(syscall.SIGPIPE)
-	app := fx.New(
+	fx.New(
 		// pixad logs with slog only; runApp prints a startup or shutdown
 		// error itself.
 		fx.NopLogger,
 		fx.Provide(
 			config.New,
 			database.New,
@@ -69,48 +61,10 @@ func run(_ *cobra.Command, _ []string) {
 			server.New,
 			middleware.New,
 			healthcheck.New,
 			// The registry /metrics serves
 			func() prometheus.Registerer { return prometheus.DefaultRegisterer },
 		),
 		fx.Provide(providers.Constructors()...),
 		fx.Invoke(
 			func(log *logger.Logger) { log.Identify() },
 			func(*server.Server) {},
 		),
-	)
+	).Run()
 	exitCode := runApp(app, os.Stderr)
 	if exitCode != 0 {
 		os.Exit(exitCode)
 	}
 }
 // runApp starts app, waits for a signal or a shutdown request, stops app,
 // and returns the status pixad exits with, as fx.App.Run does. It prints
 // a start or stop error to stderr, once, as the error that caused it:
 // dig.RootCause drops the frames fx and dig wrap around it.
 func runApp(app *fx.App, stderr io.Writer) int {
 	startCtx, cancelStart := context.WithTimeout(context.Background(), app.StartTimeout())
 	defer cancelStart()
 	err := app.Start(startCtx)
 	if err != nil {
 		_, _ = fmt.Fprintln(stderr, dig.RootCause(err))
 		return 1
 	}
 	shutdown := <-app.Wait()
 	stopCtx, cancelStop := context.WithTimeout(context.Background(), app.StopTimeout())
 	defer cancelStop()
 	err = app.Stop(stopCtx)
 	if err != nil {
 		_, _ = fmt.Fprintln(stderr, dig.RootCause(err))
 		return 1
 	}
 	return shutdown.ExitCode
 }
@@ -1,65 +0,0 @@
 package app
 import (
 	"bytes"
 	"context"
 	"errors"
 	"io"
 	"testing"
 	"go.uber.org/fx"
 )
 var errTestStopFailed = errors.New("test stop hook failed")
 // TestRunAppPrintsStopErrorOnce checks that when a stop hook fails, runApp
 // prints the hook's error once and returns exit status 1.
 func TestRunAppPrintsStopErrorOnce(t *testing.T) {
 	t.Parallel()
 	app := fx.New(
 		fx.NopLogger,
 		fx.Invoke(func(lifecycle fx.Lifecycle, shutdowner fx.Shutdowner) {
 			lifecycle.Append(fx.Hook{
 				// Ask to shut down as soon as the app has started, so
 				// that runApp goes on to stop it.
 				OnStart: func(context.Context) error { return shutdowner.Shutdown() },
 				OnStop:  func(context.Context) error { return errTestStopFailed },
 			})
 		}),
 	)
 	var stderr bytes.Buffer
 	exitCode := runApp(app, &stderr)
 	if exitCode != 1 {
 		t.Errorf("runApp() = %d, want 1", exitCode)
 	}
 	want := errTestStopFailed.Error() + "\n"
 	if stderr.String() != want {
 		t.Errorf("stderr = %q, want %q", stderr.String(), want)
 	}
 }
 // TestRunAppReturnsShutdownExitCode checks that runApp returns the exit
 // code a shutdown request names.
 func TestRunAppReturnsShutdownExitCode(t *testing.T) {
 	t.Parallel()
 	app := fx.New(
 		fx.NopLogger,
 		fx.Invoke(func(lifecycle fx.Lifecycle, shutdowner fx.Shutdowner) {
 			lifecycle.Append(fx.Hook{
 				OnStart: func(context.Context) error {
 					return shutdowner.Shutdown(fx.ExitCode(3))
 				},
 			})
 		}),
 	)
 	exitCode := runApp(app, io.Discard)
 	if exitCode != 3 {
 		t.Errorf("runApp() = %d, want 3", exitCode)
 	}
 }
@@ -1,177 +0,0 @@
 package app_test
 import (
 	"bytes"
 	"errors"
 	"fmt"
 	"net"
 	"net/http"
 	"os"
 	"os/exec"
 	"strconv"
 	"syscall"
 	"testing"
 	"time"
 	"sneak.berlin/go/pixa/internal/app"
 )
 // These tests run pixad in a child process: the test binary itself,
 // started again with runPixadInChildEnvVar set, which makes TestMain run
 // pixad instead of the tests.
 const runPixadInChildEnvVar = "TEST_RUN_PIXAD_IN_CHILD"
 const validTestSigningKey = "test-signing-key-for-app-tests-0123456789"
 func TestMain(m *testing.M) {
 	if os.Getenv(runPixadInChildEnvVar) == "1" {
 		os.Args = []string{"pixad"}
 		app.Run("test")
 		os.Exit(0)
 	}
 	os.Exit(m.Run())
 }
 // pixadCommand returns a command that runs pixad with only the given
 // environment, in an empty directory with an empty HOME, so that no
 // config file is found.
 func pixadCommand(t *testing.T, env ...string) (*exec.Cmd, *bytes.Buffer) {
 	t.Helper()
 	testBinary := os.Args[0]
 	cmd := exec.CommandContext(t.Context(), testBinary) //nolint:gosec // not tainted
 	cmd.Dir = t.TempDir()
 	// A test binary built with -cover warns on stderr at exit when
 	// GOCOVERDIR is not set.
 	cmd.Env = append([]string{
 		runPixadInChildEnvVar + "=1",
 		"HOME=" + t.TempDir(),
 		"GOCOVERDIR=" + t.TempDir(),
 	}, env...)
 	var stderr bytes.Buffer
 	cmd.Stderr = &stderr
 	return cmd, &stderr
 }
 // TestRunPrintsStartupErrorOnce checks that an invalid setting is
 // printed once, as the line that names it, and nothing else goes to
 // stderr.
 func TestRunPrintsStartupErrorOnce(t *testing.T) {
 	t.Parallel()
 	cmd, stderr := pixadCommand(t, "PIXA_SIGNING_KEY=short")
 	err := cmd.Run()
 	var exitErr *exec.ExitError
 	if !errors.As(err, &exitErr) || exitErr.ExitCode() != 1 {
 		t.Fatalf("pixad: got %v, want exit status 1; stderr:\n%s", err, stderr)
 	}
 	want := `config key "signing_key" (environment variable PIXA_SIGNING_KEY): ` +
 		"value too short: must be at least 32 characters, got 5\n"
 	if stderr.String() != want {
 		t.Errorf("stderr:\n%s\nwant:\n%s", stderr, want)
 	}
 }
 // TestRunWritesNothingToStderrOnStartAndStop starts pixad, waits until
 // it answers its health check, stops it with SIGTERM, and checks that it
 // wrote nothing to stderr.
 func TestRunWritesNothingToStderrOnStartAndStop(t *testing.T) {
 	t.Parallel()
 	port := freePort(t)
 	cmd, stderr := pixadCommand(t,
 		"PORT="+strconv.Itoa(port),
 		"PIXA_STATE_DIR="+t.TempDir(),
 		"PIXA_SIGNING_KEY="+validTestSigningKey,
 	)
 	err := cmd.Start()
 	if err != nil {
 		t.Fatalf("starting pixad: %v", err)
 	}
 	waitForHealthCheck(t, cmd, port, stderr)
 	err = cmd.Process.Signal(syscall.SIGTERM)
 	if err != nil {
 		t.Fatalf("signalling pixad: %v", err)
 	}
 	err = cmd.Wait()
 	if err != nil {
 		t.Fatalf("pixad: got %v, want exit status 0; stderr:\n%s", err, stderr)
 	}
 	if stderr.Len() != 0 {
 		t.Errorf("stderr is not empty:\n%s", stderr)
 	}
 }
 // freePort returns a TCP port on the loopback address that nothing
 // listens on.
 func freePort(t *testing.T) int {
 	t.Helper()
 	var listenConfig net.ListenConfig
 	listener, err := listenConfig.Listen(t.Context(), "tcp", "127.0.0.1:0")
 	if err != nil {
 		t.Fatalf("finding a free port: %v", err)
 	}
 	addr, ok := listener.Addr().(*net.TCPAddr)
 	if !ok {
 		t.Fatalf("listener address %v is not a TCP address", listener.Addr())
 	}
 	err = listener.Close()
 	if err != nil {
 		t.Fatalf("closing listener: %v", err)
 	}
 	return addr.Port
 }
 // waitForHealthCheck waits up to 30 seconds for pixad, started as cmd, to
 // answer its health check on port. If it does not, it stops pixad and
 // fails the test with what pixad wrote to stderr.
 func waitForHealthCheck(t *testing.T, cmd *exec.Cmd, port int, stderr *bytes.Buffer) {
 	t.Helper()
 	url := fmt.Sprintf("http://127.0.0.1:%d/.well-known/healthcheck.json", port)
 	deadline := time.Now().Add(30 * time.Second)
 	for time.Now().Before(deadline) {
 		req, err := http.NewRequestWithContext(t.Context(), http.MethodGet, url, nil)
 		if err != nil {
 			t.Fatalf("health check request: %v", err)
 		}
 		resp, err := http.DefaultClient.Do(req)
 		if err == nil {
 			_ = resp.Body.Close()
 			if resp.StatusCode == http.StatusOK {
 				return
 			}
 		}
 		time.Sleep(100 * time.Millisecond)
 	}
 	// Stop pixad first: stderr is complete, and safe to read, only once
 	// cmd.Wait has returned.
 	_ = cmd.Process.Kill()
 	_ = cmd.Wait()
 	t.Fatalf("pixad did not answer its health check on port %d; stderr:\n%s",
 		port, stderr)
 }
@@ -88,56 +88,3 @@ func TestBlockedNetworksInvalidAbortsStartup(t *testing.T) {
 		},
 	})
 }
 // TestBlockedNetworksMappedEntryIsIPv4Range checks that an entry written in
 // the IPv4-mapped form (::ffff:a.b.c.d) is kept as the IPv4 range it covers,
 // since the fetcher matches an IPv4-mapped address as the IPv4 address it
 // holds. /96, the shortest such entry, covers every IPv4 address.
 func TestBlockedNetworksMappedEntryIsIPv4Range(t *testing.T) {
 	t.Parallel()
 	yamlContent := signingKeyLine + `blocked_networks:
  - "::ffff:10.0.0.0/104"
  - "::ffff:0:0/96"
 `
 	c, err := configFromYAML(t, yamlContent)
 	if err != nil {
 		t.Fatalf("IPv4-mapped blocked_networks entries should load, got error: %v", err)
 	}
 	want := []string{"10.0.0.0/8", "0.0.0.0/0"}
 	if len(c.BlockedNetworks) != len(want) {
 		t.Fatalf("BlockedNetworks = %v, want %d entries", c.BlockedNetworks, len(want))
 	}
 	for i, w := range want {
 		if got := c.BlockedNetworks[i].String(); got != w {
 			t.Errorf("BlockedNetworks[%d] = %q, want %q", i, got, w)
 		}
 	}
 }
 // TestBlockedNetworksMappedEntryShorterThan96AbortsStartup checks that an
 // entry in the IPv4-mapped form shorter than /96, which covers more than the
 // IPv4 addresses, aborts startup with an error naming the key and the value.
 func TestBlockedNetworksMappedEntryShorterThan96AbortsStartup(t *testing.T) {
 	t.Parallel()
 	runAbortCases(t, []abortCase{
 		{
 			name: "mapped-shorter-than-96",
 			yaml: signingKeyLine + `blocked_networks:
  - "::ffff:0.0.0.0/80"
 `,
 			wantErrSubstrings: []string{keyBlockedNetworks, "::ffff:0.0.0.0/80"},
 		},
 		{
 			name: "mapped-95",
 			yaml: signingKeyLine + `blocked_networks:
  - "::ffff:0:0/95"
 `,
 			wantErrSubstrings: []string{keyBlockedNetworks},
 		},
 	})
 }
@@ -135,38 +135,10 @@ func TestCacheMaxBytesInvalidValuesAbortStartup(t *testing.T) {
 	}
 }
 // TestDefaultCacheMaxBytesAppliesFloor verifies that when 75% of the
 // free space plus what the cache holds is below 500 MiB, the default is
 // floored at DefaultCacheMaxBytesFloor.
 func TestDefaultCacheMaxBytesAppliesFloor(t *testing.T) {
 	t.Parallel()
 	cases := []struct {
 		name      string
 		freeBytes uint64
 	}{
 		{name: "100 MiB free", freeBytes: 104857600},
 		{name: "zero free", freeBytes: 0},
 		{name: "just below floor threshold", freeBytes: 699050665},
 	}
 	for _, tc := range cases {
 		t.Run(tc.name, func(t *testing.T) {
 			t.Parallel()
 			got := DefaultCacheMaxBytes(tc.freeBytes, 0)
 			if got != DefaultCacheMaxBytesFloor {
 				t.Errorf("DefaultCacheMaxBytes = %d, want floor %d",
 					got, DefaultCacheMaxBytesFloor)
 			}
 		})
 	}
 }
 // TestCacheMaxBytesExplicitIsRecorded verifies that an omitted
-// cache_max_bytes is recorded as not explicit, so pixad works out the
+// cache_max_bytes is recorded as not explicit, so the cache works out
-// default when it builds the cache, and that an explicit zero is recorded
+// the default when it opens, and that an explicit zero is recorded as
-// as explicit, so it disables the disk cache instead.
+// explicit, so it disables the disk cache instead.
 func TestCacheMaxBytesExplicitIsRecorded(t *testing.T) {
 	t.Parallel()
@@ -1,7 +1,6 @@
 package config
 import (
 	"fmt"
 	"runtime"
 	"testing"
 )
@@ -13,8 +12,8 @@ const (
 )
 // TestOmittedConcurrencyLimitsUseDefaults checks that an omitted
-// max_concurrent_processing is half the CPUs Go uses, and at least 1, and
+// max_concurrent_processing is the number of CPUs Go uses and an omitted
-// an omitted upstream_connections is 64.
+// upstream_connections is 64.
 func TestOmittedConcurrencyLimitsUseDefaults(t *testing.T) {
 	t.Parallel()
@@ -23,9 +22,9 @@ func TestOmittedConcurrencyLimitsUseDefaults(t *testing.T) {
 		t.Fatalf("minimal config should be valid, got error: %v", err)
 	}
-	if c.MaxConcurrentProcessing != max(runtime.GOMAXPROCS(0)/2, 1) {
+	if c.MaxConcurrentProcessing != runtime.GOMAXPROCS(0) {
-		t.Errorf("MaxConcurrentProcessing = %d, want %d, half the CPUs",
+		t.Errorf("MaxConcurrentProcessing = %d, want %d, one per CPU",
-			c.MaxConcurrentProcessing, max(runtime.GOMAXPROCS(0)/2, 1))
+			c.MaxConcurrentProcessing, runtime.GOMAXPROCS(0))
 	}
 	if c.UpstreamConnections != 64 {
@@ -33,36 +32,6 @@ func TestOmittedConcurrencyLimitsUseDefaults(t *testing.T) {
 	}
 }
 // TestOmittedMaxConcurrentProcessingIsHalfTheCPUsAndAtLeastOne checks
 // that an omitted max_concurrent_processing is half the CPUs Go uses,
 // rounded down, and 1 when Go uses one CPU.
 //
 //nolint:paralleltest // it sets GOMAXPROCS, which other tests read
 func TestOmittedMaxConcurrentProcessingIsHalfTheCPUsAndAtLeastOne(t *testing.T) {
 	cpusBefore := runtime.GOMAXPROCS(0)
 	t.Cleanup(func() { runtime.GOMAXPROCS(cpusBefore) })
 	for _, tc := range []struct{ cpus, want int }{
 		{1, 1}, {2, 1}, {3, 1}, {8, 4},
 	} {
 		runtime.GOMAXPROCS(tc.cpus)
 		c, err := configFromYAML(t, signingKeyLine)
 		if err != nil {
 			t.Fatalf("minimal config should be valid, got error: %v", err)
 		}
 		t.Logf("GOMAXPROCS %d: MaxConcurrentProcessing %d",
 			tc.cpus, c.MaxConcurrentProcessing)
 		if c.MaxConcurrentProcessing != tc.want {
 			t.Errorf("GOMAXPROCS %d: MaxConcurrentProcessing = %d, want %d",
 				tc.cpus, c.MaxConcurrentProcessing, tc.want)
 		}
 	}
 }
 // TestExplicitConcurrencyLimitsAreUsed checks that valid values for the
 // two limits are used as given.
 func TestExplicitConcurrencyLimitsAreUsed(t *testing.T) {
@@ -191,19 +160,3 @@ func TestConcurrencyLimitsFromEnvironment(t *testing.T) {
 		})
 	}
 }
 // TestInvalidMaxConcurrentProcessingFromEnvironmentAbortsStartup checks
 // that a PIXA_MAX_CONCURRENT_PROCESSING that is not a whole number of at
 // least 1, an empty one included, aborts startup naming the variable and
 // the key instead of taking the default.
 func TestInvalidMaxConcurrentProcessingFromEnvironmentAbortsStartup(t *testing.T) {
 	for _, value := range []string{"", " ", "0.5", "half", "-1", "4 images"} {
 		t.Run(fmt.Sprintf("value %q", value), func(t *testing.T) {
 			t.Setenv(testMaxConcurrentProcessingVar, value)
 			_, err := configFromYAML(t, signingKeyLine)
 			wantStartupError(t, err,
 				testMaxConcurrentProcessingVar, keyMaxConcurrentProcessing)
 		})
 	}
 }
@@ -1,12 +1,97 @@
 package config
 import (
 	"os"
 	"path/filepath"
 	"testing"
 	"git.eeqj.de/sneak/smartconfig"
 )
 // writeTestConfig writes yamlContent to a temp config file and returns
 // the file path.
 func writeTestConfig(t *testing.T, yamlContent string) string {
 	t.Helper()
 	tmpDir := t.TempDir()
 	configPath := filepath.Join(tmpDir, "config.yml")
 	err := os.WriteFile(configPath, []byte(yamlContent), 0o600)
 	if err != nil {
 		t.Fatalf("failed to write test config: %v", err)
 	}
 	return configPath
 }
 // checkAllowlistHosts loads the config at configPath and asserts that
 // getStringSlice returns the three expected hosts.
 func checkAllowlistHosts(t *testing.T, configPath string) {
 	t.Helper()
 	sc, err := loadTestConfig(configPath)
 	if err != nil {
 		t.Fatalf("failed to load config: %v", err)
 	}
 	hosts := getStringSlice(sc)
 	if len(hosts) != 3 {
 		t.Errorf("expected 3 hosts, got %d: %v", len(hosts), hosts)
 	}
 	expected := []string{"static.sneak.cloud", "sneak.berlin", testHostS3}
 	for i, want := range expected {
 		if i >= len(hosts) {
 			t.Errorf("missing host at index %d: want %q", i, want)
 			continue
 		}
 		if hosts[i] != want {
 			t.Errorf("host[%d] = %q, want %q", i, hosts[i], want)
 		}
 	}
 }
 func TestGetStringSlice_YAMLList(t *testing.T) {
 	t.Parallel()
 	yamlContent := `
 allowlist_hosts:
  - static.sneak.cloud
  - sneak.berlin
  - s3.sneak.cloud
 `
 	checkAllowlistHosts(t, writeTestConfig(t, yamlContent))
 }
 func TestGetStringSlice_CommaSeparated(t *testing.T) {
 	t.Parallel()
 	// Backwards compatibility with comma-separated string values.
 	yamlContent := `allowlist_hosts: "static.sneak.cloud, sneak.berlin, s3.sneak.cloud"`
 	checkAllowlistHosts(t, writeTestConfig(t, yamlContent))
 }
 func TestGetStringSlice_Empty(t *testing.T) {
 	t.Parallel()
 	configPath := writeTestConfig(t, `port: 8080`)
 	sc, err := loadTestConfig(configPath)
 	if err != nil {
 		t.Fatalf("failed to load config: %v", err)
 	}
 	hosts := getStringSlice(sc)
 	if len(hosts) != 0 {
 		t.Errorf("expected nil or empty slice, got %v", hosts)
 	}
 }
 // TestExampleConfigAllowlistsNoHost loads configs/config.example.yml
 // with a real signing key, as Getting Started in README.md has it copied
 // and edited, and checks that it allowlists no host: every image on an
@@ -15,36 +15,8 @@ import (
 	_ "modernc.org/sqlite" // SQLite driver registration
 )
 // The config keys the tests name in the errors they expect.
 const (
 	keyDebug                      = "debug"
 	keyMaintenanceMode            = "maintenance_mode"
 	keyPort                       = "port"
 	keyStateDir                   = "state_dir"
 	keySentryDSN                  = "sentry_dsn"
 	keyDBURL                      = "db_url"
 	keyMetrics                    = "metrics"
 	keyMetricsUsername            = "metrics.username"
 	keyMetricsPassword            = "metrics.password"
 	keySigningKey                 = "signing_key"
 	keyAllowlistHosts             = "allowlist_hosts"
 	keyRefererBlocklist           = "referer_blocklist"
 	keyAllowHTTP                  = "allow_http"
 	keyUpstreamConnectionsPerHost = "upstream_connections_per_host"
 	keyUpstreamConnections        = "upstream_connections"
 	keyMaxConcurrentProcessing    = "max_concurrent_processing"
 	keyCacheMaxBytes              = "cache_max_bytes"
 	keyBlockedNetworks            = "blocked_networks"
 	keyTrustedProxies             = "trusted_proxies"
 	keyAccessControlAllowOrigin   = "access_control_allow_origin"
 	keyUpstreamFetchTimeout       = "upstream_fetch_timeout"
 	keyUpstreamMaxResponseSize    = "upstream_max_response_size"
 	keyDownstreamTimeout          = "downstream_timeout"
 	keyImageRequestsPerMinute     = "image_requests_per_minute"
 )
 // validTestSigningKey is a 32-character signing key that satisfies the
-// minimum length requirement in validateSigningKey.
+// minimum length requirement in validate().
 const validTestSigningKey = "0123456789abcdef0123456789abcdef"
 // signingKeyLine is a valid signing_key config line used as the base of
@@ -163,104 +135,6 @@ func TestDefaultDBURLOpensTheDatabaseInWALMode(t *testing.T) {
 	}
 }
 // TestDerivedDBURLOpensStateDirHoldingURLCharacters opens the db_url
 // derived from a state_dir whose name holds %41, ? and #, and checks that
 // the database is state.sqlite3 in that directory, in WAL mode. Put into
 // a file: URL as it is, the name would lose its meaning: %41 is read as
 // A, and the path ends at the ?, which also loses the journal mode.
 func TestDerivedDBURLOpensStateDirHoldingURLCharacters(t *testing.T) {
 	t.Parallel()
 	stateDir := filepath.Join(t.TempDir(), "a%41b?c#d")
 	err := os.Mkdir(stateDir, 0o750)
 	if err != nil {
 		t.Fatalf("failed to create %q: %v", stateDir, err)
 	}
 	// Quoted so YAML takes the whole name as it is.
 	c, err := configFromYAML(t, signingKeyLine+"state_dir: '"+stateDir+"'\n")
 	if err != nil {
 		t.Fatalf("config with state_dir %q should be valid, got: %v", stateDir, err)
 	}
 	t.Logf("state_dir %q gives db_url %q", stateDir, c.DBURL)
 	checkDBURLOpensFileInWALMode(t, c.DBURL, filepath.Join(stateDir, "state.sqlite3"))
 }
 // TestDerivedDBURLOpensStateDirStartingWithTwoSlashes opens the db_url
 // derived from a state_dir that starts with //, and checks that the
 // database is state.sqlite3 in that directory, in WAL mode. Written right
 // after file:, such a name gives a URL starting file://, and SQLite reads
 // the first directory name as a host and refuses to open it.
 func TestDerivedDBURLOpensStateDirStartingWithTwoSlashes(t *testing.T) {
 	t.Parallel()
 	dir := t.TempDir()
 	stateDir := "/" + dir
 	c, err := configFromYAML(t, signingKeyLine+"state_dir: "+stateDir+"\n")
 	if err != nil {
 		t.Fatalf("config with state_dir %q should be valid, got: %v", stateDir, err)
 	}
 	t.Logf("state_dir %q gives db_url %q", stateDir, c.DBURL)
 	checkDBURLOpensFileInWALMode(t, c.DBURL, filepath.Join(dir, "state.sqlite3"))
 }
 // TestDerivedDBURLForRootStateDir checks the db_url derived from a
 // state_dir of /. The path written into the URL is then
 // //state.sqlite3, and written right after file: it gives a URL starting
 // file://, where SQLite reads state.sqlite3 as a host and refuses to open
 // it. The test only checks the URL, since it cannot write to /.
 func TestDerivedDBURLForRootStateDir(t *testing.T) {
 	t.Parallel()
 	c, err := configFromYAML(t, signingKeyLine+"state_dir: /\n")
 	if err != nil {
 		t.Fatalf("config with state_dir / should be valid, got: %v", err)
 	}
 	t.Logf("state_dir / gives db_url %q", c.DBURL)
 	wantDBURL := "file:////state.sqlite3?_pragma=journal_mode(WAL)"
 	if c.DBURL != wantDBURL {
 		t.Errorf("DBURL = %q, want %q", c.DBURL, wantDBURL)
 	}
 }
 // checkDBURLOpensFileInWALMode opens dbURL with the SQLite driver pixad
 // uses, and checks that the database is in WAL mode and is the file
 // dbFile.
 func checkDBURLOpensFileInWALMode(t *testing.T, dbURL, dbFile string) {
 	t.Helper()
 	db, err := sql.Open("sqlite", dbURL)
 	if err != nil {
 		t.Fatalf("failed to open %q: %v", dbURL, err)
 	}
 	t.Cleanup(func() { _ = db.Close() })
 	var journalMode string
 	err = db.QueryRowContext(t.Context(), "PRAGMA journal_mode").Scan(&journalMode)
 	if err != nil {
 		t.Fatalf("failed to read the journal mode of %q: %v", dbURL, err)
 	}
 	if journalMode != "wal" {
 		t.Errorf("journal mode of %q = %q, want wal", dbURL, journalMode)
 	}
 	_, err = os.Stat(dbFile)
 	if err != nil {
 		t.Errorf("opening %q did not create %q: %v", dbURL, dbFile, err)
 	}
 }
 func TestExplicitValidValuesAreUsed(t *testing.T) {
 	t.Parallel()
@@ -1,127 +0,0 @@
 package config
 import (
 	"os"
 	"path/filepath"
 	"regexp"
 	"strings"
 	"testing"
 )
 // TestReadmeNamesEverySetting checks that the list of settings in
 // README.md names exactly the keys of the settings table, one item each.
 // The list is the first one in the Configuration section, and it ends at
 // the first blank line. Each item starts with its key in backticks.
 func TestReadmeNamesEverySetting(t *testing.T) {
 	t.Parallel()
 	readme, err := os.ReadFile(filepath.Join("..", "..", "README.md"))
 	if err != nil {
 		t.Fatalf("failed to read README.md: %v", err)
 	}
 	_, section, found := strings.Cut(string(readme), "\n### Configuration\n")
 	if !found {
 		t.Fatal("README.md has no Configuration section")
 	}
 	// The section ends at the next heading of its level or above.
 	section, _, _ = strings.Cut(section, "\n## ")
 	section, _, _ = strings.Cut(section, "\n### ")
 	_, list, found := strings.Cut(section, "\n- ")
 	if !found {
 		t.Fatal("README.md's Configuration section has no list")
 	}
 	list, _, _ = strings.Cut("- "+list, "\n\n")
 	itemKey := regexp.MustCompile("^- `([^`]+)`")
 	named := map[string]bool{}
 	for line := range strings.SplitSeq(list, "\n") {
 		// A line that does not start with "- " goes on with the item above.
 		if !strings.HasPrefix(line, "- ") {
 			continue
 		}
 		match := itemKey.FindStringSubmatch(line)
 		if match == nil {
 			t.Errorf("README.md's list of settings has an item "+
 				"that does not start with a key in backticks: %s", line)
 			continue
 		}
 		if named[match[1]] {
 			t.Errorf("README.md's list of settings names %s twice", match[1])
 		}
 		named[match[1]] = true
 	}
 	for _, s := range new(Config).settings() {
 		if !named[s.key] {
 			t.Errorf("README.md's list of settings does not name %s", s.key)
 		}
 		delete(named, s.key)
 	}
 	for key := range named {
 		t.Errorf("README.md's list of settings names %s, "+
 			"which is not a setting", key)
 	}
 }
 // TestExampleConfigNamesEverySetting checks that
 // configs/config.example.yml names exactly the keys of the settings
 // table, each one set or commented out with "# ". A key line holds the
 // key, a colon and at most a one-word value, which tells it from a
 // comment line that starts with a word and a colon. An indented key is
 // inside the map of the key above it, as username is inside metrics.
 func TestExampleConfigNamesEverySetting(t *testing.T) {
 	t.Parallel()
 	const examplePath = "configs/config.example.yml"
 	example, err := os.ReadFile(filepath.Join("..", "..", examplePath))
 	if err != nil {
 		t.Fatalf("failed to read %s: %v", examplePath, err)
 	}
 	keyLine := regexp.MustCompile(`(?m)^(?:# )?( *)([a-z_]+):(?: \S+)?$`)
 	named := map[string]bool{}
 	var mapKey string
 	for _, match := range keyLine.FindAllStringSubmatch(string(example), -1) {
 		indent, key := match[1], match[2]
 		if indent == "" {
 			mapKey = key
 			named[key] = true
 			continue
 		}
 		// The key holding the map is not itself a setting.
 		delete(named, mapKey)
 		named[mapKey+"."+key] = true
 	}
 	// The env section sets environment variables; it is not a setting.
 	delete(named, "env")
 	for _, s := range new(Config).settings() {
 		if !named[s.key] {
 			t.Errorf("%s does not name %s", examplePath, s.key)
 		}
 		delete(named, s.key)
 	}
 	for key := range named {
 		t.Errorf("%s names %s, which is not a setting", examplePath, key)
 	}
 }
@@ -138,8 +138,7 @@ func TestPixaPortAbortsStartupPointingToPort(t *testing.T) {
 // TestSettingVariablesAndConfigPathAreAccepted checks that every
 // setting's variable and PIXA_CONFIG_PATH pass the check for unknown
-// PIXA_ variables. TestEnvironmentSetsEveryKey pins the names in the
+// PIXA_ variables. TestEnvironmentSetsEveryKey pins the names in the list.
 // settings table.
 func TestSettingVariablesAndConfigPathAreAccepted(t *testing.T) {
 	// A config file's env section loaded by another test can leave a
 	// PIXA_ variable set for the whole process, so every one is unset
@@ -160,8 +159,8 @@ func TestSettingVariablesAndConfigPathAreAccepted(t *testing.T) {
 	t.Setenv("PIXA_CONFIG_PATH", "/etc/pixa/config.yml")
-	for _, s := range new(Config).settings() {
+	for _, name := range envVarNames() {
-		t.Setenv(s.envVar, "")
+		t.Setenv(name, "")
 	}
 	err := validateKnownEnvVars()
@@ -83,41 +83,3 @@ func TestTrustedProxiesInvalidAbortsStartup(t *testing.T) {
 		},
 	})
 }
 // TestTrustedProxiesMappedEntryIsIPv4Range checks that an entry written in
 // the IPv4-mapped form (::ffff:a.b.c.d) is kept as the IPv4 range it covers,
 // since the client address is matched as the IPv4 address it holds. /96, the
 // shortest such entry, covers every IPv4 address.
 func TestTrustedProxiesMappedEntryIsIPv4Range(t *testing.T) {
 	t.Parallel()
 	c, err := configFromYAML(t, signingKeyLine+
 		`trusted_proxies: ["::ffff:10.0.0.0/104", "::ffff:0:0/96"]`+"\n")
 	if err != nil {
 		t.Fatalf("IPv4-mapped trusted_proxies entries should load: %v", err)
 	}
 	got := make([]string, len(c.TrustedProxies))
 	for i, p := range c.TrustedProxies {
 		got[i] = p.String()
 	}
 	if joined := strings.Join(got, ","); joined != "10.0.0.0/8,0.0.0.0/0" {
 		t.Errorf("TrustedProxies = %v, want 10.0.0.0/8 and 0.0.0.0/0", got)
 	}
 }
 // TestTrustedProxiesMappedEntryShorterThan96AbortsStartup checks that an
 // entry in the IPv4-mapped form shorter than /96, which covers more than the
 // IPv4 addresses, aborts startup with an error naming the key and the value.
 func TestTrustedProxiesMappedEntryShorterThan96AbortsStartup(t *testing.T) {
 	t.Parallel()
 	runAbortCases(t, []abortCase{
 		{
 			name:              "mapped-95",
 			yaml:              signingKeyLine + `trusted_proxies: ["::ffff:0:0/95"]` + "\n",
 			wantErrSubstrings: []string{keyTrustedProxies, "::ffff:0:0/95"},
 		},
 	})
 }
@@ -104,31 +104,40 @@ func writeConcurrently(t *testing.T, db *sql.DB) {
 	wg.Wait()
-	var sources int
+	var hits, sources int
-	err := db.QueryRowContext(ctx, `SELECT COUNT(*) FROM source_content`).
+	err := db.QueryRowContext(ctx, `
-		Scan(&sources)
+		SELECT hit_count, (SELECT COUNT(*) FROM source_content)
 		FROM cache_stats WHERE id = 1
 	`).Scan(&hits, &sources)
 	if err != nil {
 		t.Fatalf("failed to count the writes: %v", err)
 	}
-	if sources != totalRequests {
+	if hits != totalRequests || sources != totalRequests {
-		t.Errorf("%d source_content rows, want %d", sources, totalRequests)
+		t.Errorf("hit_count = %d and %d source_content rows, want %d of each",
 			hits, sources, totalRequests)
 	}
 }
 // writeLikeOneRequest makes the writes one request and the eviction pass
-// make: it stores a source, records a transformed image and deletes that
+// make: it counts a cache hit, stores a source, records a transformed image
-// record again.
+// and deletes that record again.
 func writeLikeOneRequest(ctx context.Context, db *sql.DB, key string) error {
-	_, err := db.ExecContext(ctx, `INSERT INTO source_content
+	_, err := db.ExecContext(ctx,
-		(source_key, size_bytes) VALUES (?, 1)`, key)
+		`UPDATE cache_stats SET hit_count = hit_count + 1 WHERE id = 1`)
 	if err != nil {
 		return fmt.Errorf("counting a cache hit: %w", err)
 	}
 	_, err = db.ExecContext(ctx, `INSERT INTO source_content
 		(content_hash, content_type, size_bytes) VALUES (?, 'image/png', 1)`, key)
 	if err != nil {
 		return fmt.Errorf("storing a source: %w", err)
 	}
 	_, err = db.ExecContext(ctx, `INSERT INTO variant_content
-		(cache_key, size_bytes) VALUES (?, 1)`, key)
+		(cache_key, size_bytes, content_type) VALUES (?, 1, 'image/png')`, key)
 	if err != nil {
 		return fmt.Errorf("recording a transformed image: %w", err)
 	}
@@ -82,11 +82,7 @@ func ParseMigrationVersion(filename string) (int, error) {
 	return version, nil
 }
-// New opens the database and applies the migrations, so that the parts
+// New creates a new Database instance.
 // fx builds after it can read the database while they are built. Its
 // stop hook closes the database. fx runs stop hooks in the reverse of the
 // order it built their parts in, so the stop hooks of those parts run
 // before this one.
 func New(lc fx.Lifecycle, params Params) (*Database, error) {
 	s := &Database{
 		log:    params.Logger.Get(),
@@ -95,16 +91,20 @@ func New(lc fx.Lifecycle, params Params) (*Database, error) {
 	s.log.Info("Database instantiated")
 	err := s.connect(context.Background())
 	if err != nil {
 		return nil, err
 	}
 	lc.Append(fx.Hook{
 		OnStart: func(ctx context.Context) error {
 			s.log.Info("Database OnStart Hook")
 			return s.connect(ctx)
 		},
 		OnStop: func(_ context.Context) error {
 			s.log.Info("Database OnStop Hook")
 			if s.db != nil {
 				return s.db.Close()
 			}
 			return nil
 		},
 	})
@@ -159,7 +159,10 @@ func TestApplyMigrations_CreatesSchemaAndTables(t *testing.T) {
 	}
 	// Verify that the application tables created by 001.sql exist.
-	tables := []string{"source_content", "negative_cache"}
+	tables := []string{
 		"source_content", "source_metadata", "output_content",
 		"request_cache", "negative_cache", "cache_stats",
 	}
 	for _, table := range tables {
 		var count int
@@ -1,51 +1,56 @@
 -- Migration 001: Initial schema
 -- Creates all tables for the pixa caching image proxy
-- Source images, one row per source URL
+-- Source content blobs
-- Files stored at: cache/sources/<ab>/<cd>/<source_key>, where source_key
+-- Files stored at: cache/sources/<ab>/<cd>/<sha256>
 -- is the SHA-256 of the source's host, path and query.
 -- fetched_at is when the cached bytes were fetched. checked_at is when
 -- upstream last sent them or answered that they had not changed.
 -- upstream_etag and upstream_last_modified are the ETag and Last-Modified
 -- headers upstream sent with the bytes, or '' when it sent none.
 CREATE TABLE IF NOT EXISTS source_content (
-    source_key TEXT PRIMARY KEY,
+    content_hash TEXT PRIMARY KEY,
    content_type TEXT NOT NULL,
    size_bytes INTEGER NOT NULL,
-    last_accessed_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    fetched_at DATETIME DEFAULT CURRENT_TIMESTAMP,
-    fetched_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    last_accessed_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP
    checked_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
    upstream_etag TEXT NOT NULL DEFAULT '',
    upstream_last_modified TEXT NOT NULL DEFAULT ''
 );
 CREATE INDEX IF NOT EXISTS idx_source_content_last_accessed
    ON source_content(last_accessed_at);
-CREATE INDEX IF NOT EXISTS idx_source_content_checked
+
-    ON source_content(checked_at);
+-- Source URL metadata - maps URLs to content hashes
 -- JSON stored at: cache/metadata/<hostname>/<path_hash>.json
 CREATE TABLE IF NOT EXISTS source_metadata (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    source_host TEXT NOT NULL,
    source_path TEXT NOT NULL,
    source_query TEXT NOT NULL DEFAULT '',
    path_hash TEXT NOT NULL,
    content_hash TEXT,
    status_code INTEGER NOT NULL,
    content_type TEXT,
    response_headers TEXT,
    fetched_at DATETIME DEFAULT CURRENT_TIMESTAMP,
    expires_at DATETIME,
    etag TEXT,
    last_modified TEXT,
    UNIQUE(source_host, source_path, source_query),
    FOREIGN KEY (content_hash) REFERENCES source_content(content_hash)
 );
 CREATE INDEX IF NOT EXISTS idx_source_meta_host ON source_metadata(source_host);
 CREATE INDEX IF NOT EXISTS idx_source_meta_path_hash ON source_metadata(path_hash);
 CREATE INDEX IF NOT EXISTS idx_source_meta_expires ON source_metadata(expires_at);
 CREATE INDEX IF NOT EXISTS idx_source_meta_content_hash ON source_metadata(content_hash);
 -- Processed variant blobs
-- Files stored at: cache/variants/<ab>/<cd>/<cache_key>. Tracked here
+-- Files stored at: cache/variants/<ab>/<cd>/<cache_key> (plus a .meta
-- (like source content blobs above) so total cache usage is known
+-- sidecar with the content type). Tracked here (like source content
-- without a directory scan, and so LRU eviction has a timestamp to order
+-- blobs above) so total cache usage is known without a directory scan,
-- on. A cache hit does not read this table: it takes the content type
+-- and so LRU eviction has a timestamp to order on.
 -- from the file's first bytes, and its last_accessed_at is written
 -- later, in a batch. checked_at is the checked_at of the source the
 -- variant was made from, when it was made or last renewed; the variant
 -- file's modification time holds the same time for cache hits.
 -- upstream_etag and upstream_last_modified are those of the source bytes
 -- the variant was made from, so the variant can still be checked with
 -- upstream after its source is evicted.
 CREATE TABLE IF NOT EXISTS variant_content (
    cache_key TEXT PRIMARY KEY,
    size_bytes INTEGER NOT NULL,
-    last_accessed_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    content_type TEXT NOT NULL,
-    checked_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
-    upstream_etag TEXT NOT NULL DEFAULT '',
+    last_accessed_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP
    upstream_last_modified TEXT NOT NULL DEFAULT ''
 );
 CREATE INDEX IF NOT EXISTS idx_variant_content_last_accessed
    ON variant_content(last_accessed_at);
 CREATE INDEX IF NOT EXISTS idx_variant_content_checked
    ON variant_content(checked_at);
 -- Total cache usage: the sum of size_bytes over source_content and
 -- variant_content, kept by the triggers below in the same statement
@@ -115,23 +120,59 @@ BEGIN
    WHERE id = 1;
 END;
-- Negative cache: source URLs whose fetch failed with an upstream error
+-- Output/transformed content blobs
-- status, or whose first bytes did not match their Content-Type. pixa does
+-- Not written: transformed images are stored in cache/variants and
-- not fetch such a URL again until its row expires.
+-- tracked in variant_content above.
 CREATE TABLE IF NOT EXISTS output_content (
    content_hash TEXT PRIMARY KEY,
    content_type TEXT NOT NULL,
    size_bytes INTEGER NOT NULL,
    fetched_at DATETIME DEFAULT CURRENT_TIMESTAMP
 );
 -- Request cache - maps full request params to output content
 CREATE TABLE IF NOT EXISTS request_cache (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    cache_key TEXT NOT NULL UNIQUE,
    source_metadata_id INTEGER NOT NULL,
    output_hash TEXT NOT NULL,
    width INTEGER NOT NULL,
    height INTEGER NOT NULL,
    format TEXT NOT NULL,
    quality INTEGER NOT NULL DEFAULT 85,
    fit_mode TEXT NOT NULL DEFAULT 'cover',
    fetched_at DATETIME DEFAULT CURRENT_TIMESTAMP,
    access_count INTEGER NOT NULL DEFAULT 1,
    FOREIGN KEY (source_metadata_id) REFERENCES source_metadata(id),
    FOREIGN KEY (output_hash) REFERENCES output_content(content_hash)
 );
 CREATE INDEX IF NOT EXISTS idx_request_cache_key ON request_cache(cache_key);
 CREATE INDEX IF NOT EXISTS idx_request_cache_source ON request_cache(source_metadata_id);
 CREATE INDEX IF NOT EXISTS idx_request_cache_output ON request_cache(output_hash);
 CREATE INDEX IF NOT EXISTS idx_request_cache_fetched ON request_cache(fetched_at);
 -- Negative cache for failed fetches (404s, timeouts, etc.)
 CREATE TABLE IF NOT EXISTS negative_cache (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    source_host TEXT NOT NULL,
    source_path TEXT NOT NULL,
    source_query TEXT NOT NULL DEFAULT '',
    status_code INTEGER NOT NULL,
    error_message TEXT,
    fetched_at DATETIME DEFAULT CURRENT_TIMESTAMP,
    expires_at DATETIME NOT NULL,
    UNIQUE(source_host, source_path, source_query)
 );
 CREATE INDEX IF NOT EXISTS idx_negative_cache_expires ON negative_cache(expires_at);
-- A random value that a login session carries from its login. pixa makes it
+-- Cache statistics for monitoring
-- when the table has no row, and each logout replaces it; a login session
+CREATE TABLE IF NOT EXISTS cache_stats (
 -- carrying another value is refused, so logging out ends every login session.
 CREATE TABLE IF NOT EXISTS logout (
    id INTEGER PRIMARY KEY CHECK (id = 1),
-    logout_value TEXT NOT NULL
+    hit_count INTEGER NOT NULL DEFAULT 0,
    miss_count INTEGER NOT NULL DEFAULT 0,
    upstream_fetch_count INTEGER NOT NULL DEFAULT 0,
    upstream_fetch_bytes INTEGER NOT NULL DEFAULT 0,
    transform_count INTEGER NOT NULL DEFAULT 0,
    last_updated_at DATETIME DEFAULT CURRENT_TIMESTAMP
 );
 INSERT OR IGNORE INTO cache_stats (id) VALUES (1);
@@ -7,15 +7,18 @@ import (
 	"github.com/fxamacker/cbor/v2"
-	"sneak.berlin/go/pixa/internal/imagerequest"
+	"sneak.berlin/go/pixa/internal/imgcache"
 	"sneak.berlin/go/pixa/internal/seal"
 )
 // Default values for optional fields.
 const (
 	DefaultQuality = 85
-	DefaultFormat  = imagerequest.FormatJXL
+	DefaultFormat  = imgcache.FormatJXL
-	DefaultFitMode = imagerequest.FitCover
+	DefaultFitMode = imgcache.FitCover
 	// HKDF salt for URL encryption key derivation
 	urlKeySalt = "pixa-urlenc-v1"
 )
 // Errors returned by encurl operations.
@@ -25,18 +28,18 @@ var (
 	ErrDecryptFailed = errors.New("failed to decrypt URL")
 )
-// payload contains all image request parameters in a compact format.
+// Payload contains all image request parameters in a compact format.
 // Field names are short to minimize encoded size.
 // Fields with omitempty use sane defaults when absent.
-type payload struct {
+type Payload struct {
 	SourceHost  string               `cbor:"h"`            // required
 	SourcePath  string               `cbor:"p"`            // required
 	SourceQuery string               `cbor:"q,omitempty"`  // optional
 	Width       int                  `cbor:"w,omitempty"`  // 0 = original
 	Height      int                  `cbor:"ht,omitempty"` // 0 = original
-	Format      imagerequest.Format `cbor:"f,omitempty"`  // default: jxl
+	Format      imgcache.ImageFormat `cbor:"f,omitempty"`  // default: jxl
 	Quality     int                  `cbor:"ql,omitempty"` // default: 85
-	FitMode     imagerequest.Fit    `cbor:"fm,omitempty"` // default: cover
+	FitMode     imgcache.FitMode     `cbor:"fm,omitempty"` // default: cover
 	ExpiresAt   int64                `cbor:"e,omitempty"`  // 0 = never expires
 }
@@ -45,35 +48,20 @@ type Generator struct {
 	key [seal.KeySize]byte
 }
-// NewGenerator creates an encrypted URL generator that encrypts its tokens
+// NewGenerator creates an encrypted URL generator with a key derived
-// with key.
+// from the signing key.
-func NewGenerator(key [seal.KeySize]byte) *Generator {
+func NewGenerator(signingKey string) (*Generator, error) {
-	return &Generator{key: key}
+	key, err := seal.DeriveKey([]byte(signingKey), urlKeySalt)
 	if err != nil {
 		return nil, err
 	}
 	return &Generator{key: key}, nil
 }
-// Generate creates an encrypted URL token from the request's source and
+// Generate creates an encrypted URL token from the payload.
-// transform, each as the request holds it, and from expires; an empty format,
+// The token is CBOR-encoded, encrypted with NaCl secretbox, and base64url-encoded.
-// a quality of 0 or an empty fit mode is left out of the token, and a zero
+func (g *Generator) Generate(p *Payload) (string, error) {
 // expires makes a token that never expires. The token is CBOR-encoded,
 // encrypted with NaCl secretbox, and base64url-encoded.
 func (g *Generator) Generate(
 	req *imagerequest.Request, expires time.Time,
 ) (string, error) {
 	p := &payload{
 		SourceHost:  req.Source.Host,
 		SourcePath:  req.Source.Path,
 		SourceQuery: req.Source.Query,
 		Width:       req.Transform.Size.Width,
 		Height:      req.Transform.Size.Height,
 		Format:      req.Transform.Format,
 		Quality:     req.Transform.Quality,
 		FitMode:     req.Transform.FitMode,
 	}
 	if !expires.IsZero() {
 		p.ExpiresAt = expires.Unix()
 	}
 	// CBOR encode the payload
 	data, err := cbor.Marshal(p)
 	if err != nil {
@@ -84,35 +72,40 @@ func (g *Generator) Generate(
 	return seal.Encrypt(g.key, data)
 }
-// Parse decrypts and validates an encrypted URL token and returns the
+// Parse decrypts and validates an encrypted URL token.
 // request it holds, with default values for omitted optional fields, and its
 // expiry. A token that never expires gives the zero time.
 // Returns ErrExpired if the token has expired, or other errors for invalid tokens.
-func (g *Generator) Parse(token string) (*imagerequest.Request, time.Time, error) {
+func (g *Generator) Parse(token string) (*Payload, error) {
 	// Decrypt
 	data, err := seal.Decrypt(g.key, token)
 	if err != nil {
 		if errors.Is(err, seal.ErrDecryptionFailed) ||
 			errors.Is(err, seal.ErrInvalidPayload) {
-			return nil, time.Time{}, ErrDecryptFailed
+			return nil, ErrDecryptFailed
 		}
-		return nil, time.Time{}, err
+		return nil, err
 	}
 	// CBOR decode
-	var p payload
+	var p Payload
 	err = cbor.Unmarshal(data, &p)
 	if err != nil {
-		return nil, time.Time{}, ErrInvalidFormat
+		return nil, ErrInvalidFormat
 	}
 	// Check expiration (0 = never expires)
 	if p.ExpiresAt != 0 && time.Now().Unix() > p.ExpiresAt {
-		return nil, time.Time{}, ErrExpired
+		return nil, ErrExpired
 	}
 	return &p, nil
 }
 // ToImageRequest converts the payload to an ImageRequest.
 // Applies default values for omitted optional fields. An ExpiresAt of 0, a URL
 // that never expires, gives the zero Expires.
 func (p *Payload) ToImageRequest() *imgcache.ImageRequest {
 	format := p.Format
 	if format == "" {
 		format = DefaultFormat
@@ -133,17 +126,44 @@ func (g *Generator) Parse(token string) (*imagerequest.Request, time.Time, error
 		expires = time.Unix(p.ExpiresAt, 0)
 	}
-	return &imagerequest.Request{
+	return &imgcache.ImageRequest{
-		Source: imagerequest.Source{
+		SourceHost:  p.SourceHost,
-			Host:  p.SourceHost,
+		SourcePath:  p.SourcePath,
-			Path:  p.SourcePath,
+		SourceQuery: p.SourceQuery,
-			Query: p.SourceQuery,
+		Size: imgcache.Size{
 			Width:  p.Width,
 			Height: p.Height,
 		},
 		Transform: imagerequest.Transform{
 			Size:    imagerequest.Size{Width: p.Width, Height: p.Height},
 		Format:  format,
 		Quality: quality,
 		FitMode: fitMode,
-		},
+		Expires: expires,
-	}, expires, nil
+	}
 }
 // FromImageRequest creates a Payload from an ImageRequest with the given expiration.
 func FromImageRequest(req *imgcache.ImageRequest, expiresAt time.Time) *Payload {
 	p := &Payload{
 		SourceHost:  req.SourceHost,
 		SourcePath:  req.SourcePath,
 		SourceQuery: req.SourceQuery,
 		Width:       req.Size.Width,
 		Height:      req.Size.Height,
 		ExpiresAt:   expiresAt.Unix(),
 	}
 	// Only set non-default values to benefit from omitempty
 	if req.Format != "" && req.Format != DefaultFormat {
 		p.Format = req.Format
 	}
 	if req.Quality != 0 && req.Quality != DefaultQuality {
 		p.Quality = req.Quality
 	}
 	if req.FitMode != "" && req.FitMode != DefaultFitMode {
 		p.FitMode = req.FitMode
 	}
 	return p
 }
@@ -6,8 +6,7 @@ import (
 	"time"
 	"sneak.berlin/go/pixa/internal/encurl"
-	"sneak.berlin/go/pixa/internal/imagerequest"
+	"sneak.berlin/go/pixa/internal/imgcache"
 	"sneak.berlin/go/pixa/internal/seal"
 )
 // Shared test fixture strings.
@@ -20,29 +19,24 @@ const (
 func TestGenerator_GenerateAndParse(t *testing.T) {
 	t.Parallel()
-	keys, err := seal.DeriveKeys("test-signing-key-12345")
+	gen, err := encurl.NewGenerator("test-signing-key-12345")
 	if err != nil {
-		t.Fatalf("seal.DeriveKeys() error = %v", err)
+		t.Fatalf("NewGenerator() error = %v", err)
 	}
-	gen := encurl.NewGenerator(keys.EncryptedURLKey)
+	payload := &encurl.Payload{
-
+		SourceHost:  testSourceHost,
-	req := &imagerequest.Request{
+		SourcePath:  testSourcePath,
-		Source: imagerequest.Source{
+		SourceQuery: testSourceQuery,
-			Host:  testSourceHost,
+		Width:       800,
-			Path:  testSourcePath,
+		Height:      600,
-			Query: testSourceQuery,
+		Format:      imgcache.FormatWebP,
 		},
 		Transform: imagerequest.Transform{
 			Size:    imagerequest.Size{Width: 800, Height: 600},
 			Format:  imagerequest.FormatWebP,
 		Quality:     90,
-			FitMode: imagerequest.FitContain,
+		FitMode:     imgcache.FitContain,
-		},
+		ExpiresAt:   time.Now().Add(time.Hour).Unix(),
 	}
 	expires := time.Now().Add(time.Hour)
-	token, err := gen.Generate(req, expires)
+	token, err := gen.Generate(payload)
 	if err != nil {
 		t.Fatalf("Generate() error = %v", err)
 	}
@@ -51,73 +45,66 @@ func TestGenerator_GenerateAndParse(t *testing.T) {
 		t.Fatal("Generate() returned empty token")
 	}
-	parsed, parsedExpires, err := gen.Parse(token)
+	parsed, err := gen.Parse(token)
 	if err != nil {
 		t.Fatalf("Parse() error = %v", err)
 	}
 	// Verify all fields
-	if parsed.Source.Host != req.Source.Host {
+	if parsed.SourceHost != payload.SourceHost {
-		t.Errorf("SourceHost = %q, want %q", parsed.Source.Host, req.Source.Host)
+		t.Errorf("SourceHost = %q, want %q", parsed.SourceHost, payload.SourceHost)
 	}
-	if parsed.Source.Path != req.Source.Path {
+	if parsed.SourcePath != payload.SourcePath {
-		t.Errorf("SourcePath = %q, want %q", parsed.Source.Path, req.Source.Path)
+		t.Errorf("SourcePath = %q, want %q", parsed.SourcePath, payload.SourcePath)
 	}
-	if parsed.Source.Query != req.Source.Query {
+	if parsed.SourceQuery != payload.SourceQuery {
-		t.Errorf("SourceQuery = %q, want %q", parsed.Source.Query, req.Source.Query)
+		t.Errorf("SourceQuery = %q, want %q", parsed.SourceQuery, payload.SourceQuery)
 	}
-	if parsed.Transform.Size.Width != req.Transform.Size.Width {
+	if parsed.Width != payload.Width {
-		t.Errorf("Width = %d, want %d",
+		t.Errorf("Width = %d, want %d", parsed.Width, payload.Width)
 			parsed.Transform.Size.Width, req.Transform.Size.Width)
 	}
-	if parsed.Transform.Size.Height != req.Transform.Size.Height {
+	if parsed.Height != payload.Height {
-		t.Errorf("Height = %d, want %d",
+		t.Errorf("Height = %d, want %d", parsed.Height, payload.Height)
 			parsed.Transform.Size.Height, req.Transform.Size.Height)
 	}
-	if parsed.Transform.Format != req.Transform.Format {
+	if parsed.Format != payload.Format {
-		t.Errorf("Format = %q, want %q",
+		t.Errorf("Format = %q, want %q", parsed.Format, payload.Format)
 			parsed.Transform.Format, req.Transform.Format)
 	}
-	if parsed.Transform.Quality != req.Transform.Quality {
+	if parsed.Quality != payload.Quality {
-		t.Errorf("Quality = %d, want %d",
+		t.Errorf("Quality = %d, want %d", parsed.Quality, payload.Quality)
 			parsed.Transform.Quality, req.Transform.Quality)
 	}
-	if parsed.Transform.FitMode != req.Transform.FitMode {
+	if parsed.FitMode != payload.FitMode {
-		t.Errorf("FitMode = %q, want %q",
+		t.Errorf("FitMode = %q, want %q", parsed.FitMode, payload.FitMode)
 			parsed.Transform.FitMode, req.Transform.FitMode)
 	}
-	if parsedExpires.Unix() != expires.Unix() {
+	if parsed.ExpiresAt != payload.ExpiresAt {
-		t.Errorf("ExpiresAt = %d, want %d", parsedExpires.Unix(), expires.Unix())
+		t.Errorf("ExpiresAt = %d, want %d", parsed.ExpiresAt, payload.ExpiresAt)
 	}
 }
 func TestGenerator_Parse_Expired(t *testing.T) {
 	t.Parallel()
-	keys, _ := seal.DeriveKeys("test-signing-key-12345")
+	gen, _ := encurl.NewGenerator("test-signing-key-12345")
 	gen := encurl.NewGenerator(keys.EncryptedURLKey)
-	req := &imagerequest.Request{
+	payload := &encurl.Payload{
-		Source: imagerequest.Source{
+		SourceHost: testSourceHost,
-			Host: testSourceHost,
+		SourcePath: testSourcePath,
-			Path: testSourcePath,
+		ExpiresAt:  time.Now().Add(-time.Hour).Unix(), // Already expired
 		},
 	}
-	token, err := gen.Generate(req, time.Now().Add(-time.Hour)) // Already expired
+	token, err := gen.Generate(payload)
 	if err != nil {
 		t.Fatalf("Generate() error = %v", err)
 	}
-	_, _, err = gen.Parse(token)
+	_, err = gen.Parse(token)
 	if err == nil {
 		t.Error("Parse() should fail for expired token")
 	}
@@ -130,10 +117,9 @@ func TestGenerator_Parse_Expired(t *testing.T) {
 func TestGenerator_Parse_InvalidToken(t *testing.T) {
 	t.Parallel()
-	keys, _ := seal.DeriveKeys("test-signing-key-12345")
+	gen, _ := encurl.NewGenerator("test-signing-key-12345")
 	gen := encurl.NewGenerator(keys.EncryptedURLKey)
-	_, _, err := gen.Parse("not-a-valid-token")
+	_, err := gen.Parse("not-a-valid-token")
 	if err == nil {
 		t.Error("Parse() should fail for invalid token")
 	}
@@ -142,17 +128,15 @@ func TestGenerator_Parse_InvalidToken(t *testing.T) {
 func TestGenerator_Parse_TamperedToken(t *testing.T) {
 	t.Parallel()
-	keys, _ := seal.DeriveKeys("test-signing-key-12345")
+	gen, _ := encurl.NewGenerator("test-signing-key-12345")
 	gen := encurl.NewGenerator(keys.EncryptedURLKey)
-	req := &imagerequest.Request{
+	payload := &encurl.Payload{
-		Source: imagerequest.Source{
+		SourceHost: testSourceHost,
-			Host: testSourceHost,
+		SourcePath: testSourcePath,
-			Path: testSourcePath,
+		ExpiresAt:  time.Now().Add(time.Hour).Unix(),
 		},
 	}
-	token, _ := gen.Generate(req, time.Now().Add(time.Hour))
+	token, _ := gen.Generate(payload)
 	// Tamper with the token
 	tampered := []byte(token)
@@ -160,7 +144,7 @@ func TestGenerator_Parse_TamperedToken(t *testing.T) {
 		tampered[10] ^= 0x01
 	}
-	_, _, err := gen.Parse(string(tampered))
+	_, err := gen.Parse(string(tampered))
 	if err == nil {
 		t.Error("Parse() should fail for tampered token")
 	}
@@ -169,78 +153,172 @@ func TestGenerator_Parse_TamperedToken(t *testing.T) {
 func TestGenerator_Parse_WrongKey(t *testing.T) {
 	t.Parallel()
-	keys1, _ := seal.DeriveKeys("signing-key-1")
+	gen1, _ := encurl.NewGenerator("signing-key-1")
-	keys2, _ := seal.DeriveKeys("signing-key-2")
+	gen2, _ := encurl.NewGenerator("signing-key-2")
 	gen1 := encurl.NewGenerator(keys1.EncryptedURLKey)
 	gen2 := encurl.NewGenerator(keys2.EncryptedURLKey)
-	req := &imagerequest.Request{
+	payload := &encurl.Payload{
-		Source: imagerequest.Source{
+		SourceHost: testSourceHost,
-			Host: testSourceHost,
+		SourcePath: testSourcePath,
-			Path: testSourcePath,
+		ExpiresAt:  time.Now().Add(time.Hour).Unix(),
 		},
 	}
-	token, _ := gen1.Generate(req, time.Now().Add(time.Hour))
+	token, _ := gen1.Generate(payload)
-	_, _, err := gen2.Parse(token)
+	_, err := gen2.Parse(token)
 	if err == nil {
 		t.Error("Parse() should fail with different signing key")
 	}
 }
-func TestGenerator_Parse_Defaults(t *testing.T) {
+func TestPayload_ToImageRequest(t *testing.T) {
 	t.Parallel()
-	keys, _ := seal.DeriveKeys("test-signing-key-12345")
+	payload := &encurl.Payload{
-	gen := encurl.NewGenerator(keys.EncryptedURLKey)
+		SourceHost:  testSourceHost,
-
+		SourcePath:  testSourcePath,
-	// Request with only required fields - should get defaults
+		SourceQuery: testSourceQuery,
-	token, err := gen.Generate(&imagerequest.Request{
+		Width:       800,
-		Source: imagerequest.Source{
+		Height:      600,
-			Host: testSourceHost,
+		Format:      imgcache.FormatWebP,
-			Path: testSourcePath,
+		Quality:     90,
-		},
+		FitMode:     imgcache.FitContain,
-	}, time.Now().Add(time.Hour))
+		ExpiresAt:   time.Now().Add(time.Hour).Unix(),
 	if err != nil {
 		t.Fatalf("Generate() error = %v", err)
 	}
-	req, _, err := gen.Parse(token)
+	req := payload.ToImageRequest()
-	if err != nil {
+
-		t.Fatalf("Parse() error = %v", err)
+	if req.SourceHost != payload.SourceHost {
 		t.Errorf("SourceHost = %q, want %q", req.SourceHost, payload.SourceHost)
 	}
-	if req.Transform.Format != encurl.DefaultFormat {
+	if req.SourcePath != payload.SourcePath {
-		t.Errorf("Format = %q, want default %q",
+		t.Errorf("SourcePath = %q, want %q", req.SourcePath, payload.SourcePath)
 			req.Transform.Format, encurl.DefaultFormat)
 	}
-	if req.Transform.Quality != encurl.DefaultQuality {
+	if req.SourceQuery != payload.SourceQuery {
-		t.Errorf("Quality = %d, want default %d",
+		t.Errorf("SourceQuery = %q, want %q", req.SourceQuery, payload.SourceQuery)
 			req.Transform.Quality, encurl.DefaultQuality)
 	}
-	if req.Transform.FitMode != encurl.DefaultFitMode {
+	if req.Size.Width != payload.Width {
-		t.Errorf("FitMode = %q, want default %q",
+		t.Errorf("Width = %d, want %d", req.Size.Width, payload.Width)
-			req.Transform.FitMode, encurl.DefaultFitMode)
+	}
 	if req.Size.Height != payload.Height {
 		t.Errorf("Height = %d, want %d", req.Size.Height, payload.Height)
 	}
 	if req.Format != payload.Format {
 		t.Errorf("Format = %q, want %q", req.Format, payload.Format)
 	}
 	if req.Quality != payload.Quality {
 		t.Errorf("Quality = %d, want %d", req.Quality, payload.Quality)
 	}
 	if req.FitMode != payload.FitMode {
 		t.Errorf("FitMode = %q, want %q", req.FitMode, payload.FitMode)
 	}
 }
 func TestPayload_ToImageRequest_Defaults(t *testing.T) {
 	t.Parallel()
 	// Payload with only required fields - should get defaults
 	payload := &encurl.Payload{
 		SourceHost: testSourceHost,
 		SourcePath: testSourcePath,
 		ExpiresAt:  time.Now().Add(time.Hour).Unix(),
 	}
 	req := payload.ToImageRequest()
 	if req.Format != encurl.DefaultFormat {
 		t.Errorf("Format = %q, want default %q", req.Format, encurl.DefaultFormat)
 	}
 	if req.Quality != encurl.DefaultQuality {
 		t.Errorf("Quality = %d, want default %d", req.Quality, encurl.DefaultQuality)
 	}
 	if req.FitMode != encurl.DefaultFitMode {
 		t.Errorf("FitMode = %q, want default %q", req.FitMode, encurl.DefaultFitMode)
 	}
 }
 func TestFromImageRequest(t *testing.T) {
 	t.Parallel()
 	req := &imgcache.ImageRequest{
 		SourceHost:  testSourceHost,
 		SourcePath:  testSourcePath,
 		SourceQuery: testSourceQuery,
 		Size:        imgcache.Size{Width: 800, Height: 600},
 		Format:      imgcache.FormatWebP,
 		Quality:     90,
 		FitMode:     imgcache.FitContain,
 	}
 	expiresAt := time.Now().Add(time.Hour)
 	payload := encurl.FromImageRequest(req, expiresAt)
 	if payload.SourceHost != req.SourceHost {
 		t.Errorf("SourceHost = %q, want %q", payload.SourceHost, req.SourceHost)
 	}
 	if payload.SourcePath != req.SourcePath {
 		t.Errorf("SourcePath = %q, want %q", payload.SourcePath, req.SourcePath)
 	}
 	if payload.Width != req.Size.Width {
 		t.Errorf("Width = %d, want %d", payload.Width, req.Size.Width)
 	}
 	if payload.ExpiresAt != expiresAt.Unix() {
 		t.Errorf("ExpiresAt = %d, want %d", payload.ExpiresAt, expiresAt.Unix())
 	}
 }
 func TestFromImageRequest_OmitsDefaults(t *testing.T) {
 	t.Parallel()
 	// Request with default values - payload should omit them for
 	// smaller encoding
 	req := &imgcache.ImageRequest{
 		SourceHost: testSourceHost,
 		SourcePath: testSourcePath,
 		Format:     encurl.DefaultFormat,
 		Quality:    encurl.DefaultQuality,
 		FitMode:    encurl.DefaultFitMode,
 	}
 	payload := encurl.FromImageRequest(req, time.Now().Add(time.Hour))
 	// These should be zero/empty because they match defaults
 	if payload.Format != "" {
 		t.Errorf("Format should be empty for default, got %q", payload.Format)
 	}
 	if payload.Quality != 0 {
 		t.Errorf("Quality should be 0 for default, got %d", payload.Quality)
 	}
 	if payload.FitMode != "" {
 		t.Errorf("FitMode should be empty for default, got %q", payload.FitMode)
 	}
 }
 func TestGenerator_TokenIsURLSafe(t *testing.T) {
 	t.Parallel()
-	keys, _ := seal.DeriveKeys("test-signing-key-12345")
+	gen, _ := encurl.NewGenerator("test-signing-key-12345")
 	gen := encurl.NewGenerator(keys.EncryptedURLKey)
-	req := &imagerequest.Request{
+	payload := &encurl.Payload{
-		Source: imagerequest.Source{
+		SourceHost: testSourceHost,
-			Host: testSourceHost,
+		SourcePath: testSourcePath,
-			Path: testSourcePath,
+		ExpiresAt:  time.Now().Add(time.Hour).Unix(),
 		},
 	}
-	token, _ := gen.Generate(req, time.Now().Add(time.Hour))
+	token, _ := gen.Generate(payload)
 	// Check that token only contains URL-safe characters
 	for _, c := range token {
@@ -9,14 +9,12 @@ import (
 	"math"
 	"net/http"
 	"net/url"
 	"slices"
 	"strconv"
 	"strings"
 	"time"
 	"sneak.berlin/go/pixa/internal/clientip"
 	"sneak.berlin/go/pixa/internal/encurl"
-	"sneak.berlin/go/pixa/internal/imagerequest"
+	"sneak.berlin/go/pixa/internal/imgcache"
 	"sneak.berlin/go/pixa/internal/templates"
 )
@@ -91,18 +89,10 @@ func (s *Handlers) handleLoginPost(w http.ResponseWriter, r *http.Request) {
 	http.Redirect(w, r, "/", http.StatusSeeOther)
 }
-// HandleLogout logs out, which ends every login session (see
+// HandleLogout clears the session and redirects to login.
 // session.Manager.Logout), and redirects to login.
 func (s *Handlers) HandleLogout() http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
-		err := s.sessMgr.Logout(w, r)
+		s.sessMgr.ClearSession(w)
 		if err != nil {
 			s.log.Error("failed to log out", "error", err)
 			http.Error(w, "Failed to log out", http.StatusInternalServerError)
 			return
 		}
 		http.Redirect(w, r, "/", http.StatusSeeOther)
 	}
 }
@@ -127,7 +117,7 @@ func (s *Handlers) HandleGenerateURL() http.HandlerFunc {
 		sourceURL := r.FormValue("url")
 		// Validate source URL
-		parsed, err := parseSourceURL(sourceURL)
+		parsed, err := url.Parse(sourceURL)
 		if err != nil || parsed.Host == "" {
 			s.renderGeneratorWithForm(w, r, "Invalid source URL", r.Form,
 				http.StatusBadRequest)
@@ -135,17 +125,7 @@ func (s *Handlers) HandleGenerateURL() http.HandlerFunc {
 			return
 		}
-		// /v1/image/ refuses a ".." segment in the source path, and so does
+		payload, expiresAt, ttl, err := buildGeneratePayload(parsed, r.Form)
 		// the generator. The path is decoded, so %2e%2e counts too
 		if slices.Contains(strings.Split(parsed.Path, "/"), "..") {
 			s.renderGeneratorWithForm(w, r,
 				"Source URL path cannot hold a .. segment", r.Form,
 				http.StatusBadRequest)
 			return
 		}
 		req, expiresAt, ttl, err := buildGenerateRequest(parsed, r.Form)
 		if err != nil {
 			s.renderGeneratorWithForm(w, r, err.Error(), r.Form,
 				http.StatusBadRequest)
@@ -153,20 +133,8 @@ func (s *Handlers) HandleGenerateURL() http.HandlerFunc {
 			return
 		}
 		// The image URL must fetch the source URL as it was written. The
 		// fetcher fetches over http only when allow_http is set.
 		fetchURL := req.Source.URL(s.config.AllowHTTP)
 		if !fetchedAsWritten(parsed, fetchURL) {
 			s.renderGeneratorWithForm(w, r, "Source URL cannot be fetched as "+
 				"written: pixa would fetch "+fetchURL.String(),
 				r.Form, http.StatusBadRequest)
 			return
 		}
 		// Generate encrypted token
-		token, err := s.encGen.Generate(req, expiresAt)
+		token, err := s.encGen.Generate(payload)
 		if err != nil {
 			s.log.Error("failed to generate encrypted URL", "error", err)
 			s.renderGeneratorWithForm(w, r, "Failed to generate URL", r.Form,
@@ -197,55 +165,14 @@ func (s *Handlers) HandleGenerateURL() http.HandlerFunc {
 	}
 }
-// parseSourceURL parses the source URL entered on the generator page with its
+// buildGeneratePayload parses the numeric form fields and assembles the
-// host lower-cased and an empty path written as "/", as /v1/image/ reads a
+// encrypted URL payload. ttl=0 means never expires (ExpiresAt stays 0). A
-// source URL, so that each spelling of one source URL makes one cache key and
+// non-numeric or out-of-range width, height, quality or ttl, or an
-// one upstream request.
+// unrecognized fit mode, is a client error naming the offending field. The
-func parseSourceURL(sourceURL string) (*url.URL, error) {
+// format field is passed through unchecked.
-	parsed, err := url.Parse(sourceURL)
+func buildGeneratePayload(
 	if err != nil {
 		return nil, err
 	}
 	parsed.Host = strings.ToLower(parsed.Host)
 	if parsed.Path == "" {
 		parsed.Path = "/"
 	}
 	return parsed, nil
 }
 // fetchedAsWritten reports whether fetchURL, the URL pixa fetches for an
 // image URL made from the source URL source, is source as it was written,
 // apart from the scheme, which the token does not keep. It is not when source
 // holds a user name and password, which the token does not keep either, or a
 // "?" with no query after it. The token keeps the source path decoded and
 // pixa fetches it percent-encoded again, so a path written another way, such
 // as with %2F, is fetched as another path. url.URL keeps the path as written
 // in RawPath when it is not the decoded path percent-encoded again.
 // EscapedPath ignores RawPath when it also holds a character net/url encodes,
 // such as a space, so RawPath is compared itself.
 func fetchedAsWritten(source, fetchURL *url.URL) bool {
 	writtenPath := source.RawPath
 	if writtenPath == "" {
 		writtenPath = source.EscapedPath()
 	}
 	return source.User == nil && !source.ForceQuery &&
 		fetchURL.EscapedPath() == writtenPath &&
 		fetchURL.RawQuery == source.RawQuery
 }
 // buildGenerateRequest parses the numeric form fields and assembles the
 // image request the encrypted URL's token is made from, and its expiry.
 // ttl=0 means never expires (the expiry is the zero time). A non-numeric or
 // out-of-range width, height, quality or ttl, or an unrecognized fit mode, is
 // a client error naming the offending field. The format field is passed
 // through unchecked.
 func buildGenerateRequest(
 	parsed *url.URL, form url.Values,
-) (*imagerequest.Request, time.Time, int, error) {
+) (*encurl.Payload, time.Time, int, error) {
 	width, err := parseFormDimension(form, "width")
 	if err != nil {
 		return nil, time.Time{}, 0, err
@@ -267,39 +194,42 @@ func buildGenerateRequest(
 		return nil, time.Time{}, 0, err
 	}
-	fitMode := imagerequest.Fit(form.Get("fit"))
+	fitMode := imgcache.FitMode(form.Get("fit"))
-	err = imagerequest.ValidateFitMode(fitMode)
+	err = imgcache.ValidateFitMode(fitMode)
 	if err != nil {
 		return nil, time.Time{}, 0,
-			fmt.Errorf("%w: %s", imagerequest.ErrInvalidFitMode, form.Get("fit"))
+			fmt.Errorf("%w: %s", imgcache.ErrInvalidFitMode, form.Get("fit"))
 	}
-	var expiresAt time.Time
+	var (
 		expiresAt     time.Time
 		expiresAtUnix int64
 	)
 	if ttl > 0 {
 		expiresAt = time.Now().Add(time.Duration(ttl) * time.Second)
 		expiresAtUnix = expiresAt.Unix()
 	}
-	req := &imagerequest.Request{
+	payload := &encurl.Payload{
-		Source: imagerequest.Source{
+		SourceHost:  parsed.Host,
-			Host:  parsed.Host,
+		SourcePath:  parsed.Path,
-			Path:  parsed.Path,
+		SourceQuery: parsed.RawQuery,
-			Query: parsed.RawQuery,
+		Width:       width,
-		},
+		Height:      height,
-		Transform: imagerequest.Transform{
+		Format:      imgcache.ImageFormat(form.Get("format")),
 			Size:    imagerequest.Size{Width: width, Height: height},
 			Format:  imagerequest.Format(form.Get("format")),
 		Quality:     quality,
 		FitMode:     fitMode,
-		},
+		ExpiresAt:   expiresAtUnix,
 	}
-	return req, expiresAt, ttl, nil
+	return payload, expiresAt, ttl, nil
 }
 // parseFormDimension reads an optional width or height form field. An empty
 // value means "original size" (0). A non-numeric value, or one
-// imagerequest.ValidateDimension rejects, is an error naming the field.
+// imgcache.ValidateDimension rejects, is an error naming the field.
 func parseFormDimension(form url.Values, field string) (int, error) {
 	raw := form.Get(field)
 	if raw == "" {
@@ -311,7 +241,7 @@ func parseFormDimension(form url.Values, field string) (int, error) {
 		return 0, fmt.Errorf("%w %s: not a number", errInvalidFormField, field)
 	}
-	err = imagerequest.ValidateDimension(field, value)
+	err = imgcache.ValidateDimension(field, value)
 	if err != nil {
 		return 0, err
 	}
@@ -14,7 +14,6 @@ import (
 	"sneak.berlin/go/pixa/internal/config"
 	"sneak.berlin/go/pixa/internal/encurl"
 	"sneak.berlin/go/pixa/internal/seal"
 	"sneak.berlin/go/pixa/internal/session"
 )
@@ -45,17 +44,27 @@ func newCSRFTestRouter(t *testing.T) (*Handlers, http.Handler) {
 	cfg := &config.Config{SigningKey: testSigningKey, Debug: true}
-	keys, err := seal.DeriveKeys(testSigningKey)
+	sessMgr, err := session.NewManager(testSigningKey)
 	if err != nil {
-		t.Fatalf("seal.DeriveKeys() error = %v", err)
+		t.Fatalf("session.NewManager() error = %v", err)
 	}
 	encGen, err := encurl.NewGenerator(testSigningKey)
 	if err != nil {
 		t.Fatalf("encurl.NewGenerator() error = %v", err)
 	}
 	protect, err := newCSRFProtect(testSigningKey, cfg.Debug)
 	if err != nil {
 		t.Fatalf("newCSRFProtect() error = %v", err)
 	}
 	h := &Handlers{
 		log:         slog.New(slog.DiscardHandler),
 		config:      cfg,
-		sessMgr:     session.NewManager(keys.SessionHashKey, keys.SessionBlockKey),
+		sessMgr:     sessMgr,
-		encGen:      encurl.NewGenerator(keys.EncryptedURLKey),
+		encGen:      encGen,
-		csrfProtect: newCSRFProtect(keys.CSRFKey, cfg.Debug, slog.New(slog.DiscardHandler)),
+		csrfProtect: protect,
 	}
 	r := chi.NewRouter()
@@ -11,7 +11,7 @@ import (
 	"time"
 	"sneak.berlin/go/pixa/internal/encurl"
-	"sneak.berlin/go/pixa/internal/imagerequest"
+	"sneak.berlin/go/pixa/internal/imgcache"
 )
 // Generator form field names, and a value that is not a number.
@@ -125,10 +125,10 @@ func TestGeneratePostRejectsBadField(t *testing.T) {
 	}
 }
-// TestBuildGenerateRequestDefaultAndLimits verifies that an empty quality
+// TestBuildGeneratePayloadDefaultAndLimits verifies that an empty quality
 // takes the default, and that the largest accepted width, height, quality and
 // ttl are accepted with an expiry still in the future.
-func TestBuildGenerateRequestDefaultAndLimits(t *testing.T) {
+func TestBuildGeneratePayloadDefaultAndLimits(t *testing.T) {
 	t.Parallel()
 	parsed, err := url.Parse(testSourceURL)
@@ -136,19 +136,19 @@ func TestBuildGenerateRequestDefaultAndLimits(t *testing.T) {
 		t.Fatalf("url.Parse() error = %v", err)
 	}
-	req, _, _, err := buildGenerateRequest(parsed, url.Values{})
+	payload, _, _, err := buildGeneratePayload(parsed, url.Values{})
 	if err != nil {
 		t.Fatalf("empty form: error = %v", err)
 	}
-	if req.Transform.Quality != encurl.DefaultQuality {
+	if payload.Quality != encurl.DefaultQuality {
 		t.Errorf("empty quality gave %d, want %d",
-			req.Transform.Quality, encurl.DefaultQuality)
+			payload.Quality, encurl.DefaultQuality)
 	}
-	_, expiresAt, _, err := buildGenerateRequest(parsed, url.Values{
+	_, expiresAt, _, err := buildGeneratePayload(parsed, url.Values{
-		widthField:   {strconv.Itoa(imagerequest.MaxDimension)},
+		widthField:   {strconv.Itoa(imgcache.MaxDimension)},
-		heightField:  {strconv.Itoa(imagerequest.MaxDimension)},
+		heightField:  {strconv.Itoa(imgcache.MaxDimension)},
 		qualityField: {strconv.Itoa(maxQuality)},
 		ttlField:     {strconv.Itoa(maxTTL)},
 	})
@@ -10,7 +10,6 @@ import (
 	"testing"
 	"sneak.berlin/go/pixa/internal/config"
 	"sneak.berlin/go/pixa/internal/seal"
 	"sneak.berlin/go/pixa/internal/session"
 )
@@ -23,15 +22,15 @@ func TestLoginLogLeavesOutSubmittedKey(t *testing.T) {
 	var buf bytes.Buffer
-	keys, err := seal.DeriveKeys(testSigningKey)
+	sessMgr, err := session.NewManager(testSigningKey)
 	if err != nil {
-		t.Fatalf("seal.DeriveKeys() error = %v", err)
+		t.Fatalf("session.NewManager() error = %v", err)
 	}
 	h := &Handlers{
 		log:     slog.New(slog.NewJSONHandler(&buf, nil)),
 		config:  &config.Config{SigningKey: testSigningKey},
-		sessMgr: session.NewManager(keys.SessionHashKey, keys.SessionBlockKey),
+		sessMgr: sessMgr,
 	}
 	submittedKeys := []string{wrongKey, testSigningKey}
@@ -10,8 +10,7 @@ import (
 	"testing"
 	"time"
-	"sneak.berlin/go/pixa/internal/imagerequest"
+	"sneak.berlin/go/pixa/internal/imgcache"
 	"sneak.berlin/go/pixa/internal/seal"
 	"sneak.berlin/go/pixa/internal/session"
 )
@@ -186,103 +185,6 @@ func TestHandleLogout_ClearsSessionCookie(t *testing.T) {
 	}
 }
 // TestHandleLogout_EndsCopiedSession verifies that after POST /logout a copy
 // of the session cookie taken before it shows the login page, not the
 // generator page.
 func TestHandleLogout_EndsCopiedSession(t *testing.T) {
 	t.Parallel()
 	h, srv := newCSRFTestRouter(t)
 	copied := newSessionCookie(t, h)
 	req := httptest.NewRequestWithContext(
 		t.Context(), http.MethodPost, "/logout", nil)
 	req.AddCookie(copied)
 	rec := httptest.NewRecorder()
 	h.HandleLogout().ServeHTTP(rec, req)
 	if rec.Code != http.StatusSeeOther {
 		t.Fatalf("POST /logout status = %d, want %d",
 			rec.Code, http.StatusSeeOther)
 	}
 	req = httptest.NewRequestWithContext(t.Context(), http.MethodGet, "/", nil)
 	req.AddCookie(copied)
 	rec = httptest.NewRecorder()
 	srv.ServeHTTP(rec, req)
 	body := rec.Body.String()
 	t.Logf("GET / with the copied cookie: status %d, login page %v",
 		rec.Code, strings.Contains(body, loginForm))
 	if !strings.Contains(body, loginForm) || strings.Contains(body, generatorForm) {
 		t.Error("a cookie copied before /logout still opens the generator page")
 	}
 }
 // TestHandleLogout_SaveFails_Answers500 verifies that when the logout cannot
 // be saved in the database, POST /logout answers 500, leaves the session
 // cookie in place and ends no session.
 func TestHandleLogout_SaveFails_Answers500(t *testing.T) {
 	t.Parallel()
 	h, srv := newCSRFTestRouter(t)
 	db := setupTestDB(t)
 	keys, err := seal.DeriveKeys(testSigningKey)
 	if err != nil {
 		t.Fatalf("seal.DeriveKeys() error = %v", err)
 	}
 	sessMgr, err := session.NewManagerWithDatabase(
 		t.Context(), keys.SessionHashKey, keys.SessionBlockKey, db)
 	if err != nil {
 		t.Fatalf("session.NewManagerWithDatabase() error = %v", err)
 	}
 	h.sessMgr = sessMgr
 	cookie := newSessionCookie(t, h)
 	// Saving the logout fails on a closed database.
 	err = db.Close()
 	if err != nil {
 		t.Fatalf("closing the database: %v", err)
 	}
 	req := httptest.NewRequestWithContext(
 		t.Context(), http.MethodPost, "/logout", nil)
 	req.AddCookie(cookie)
 	rec := httptest.NewRecorder()
 	h.HandleLogout().ServeHTTP(rec, req)
 	t.Logf("POST /logout: status %d, Set-Cookie %q",
 		rec.Code, rec.Header().Get("Set-Cookie"))
 	if rec.Code != http.StatusInternalServerError {
 		t.Errorf("POST /logout status = %d, want %d",
 			rec.Code, http.StatusInternalServerError)
 	}
 	if c := findSessionCookie(rec); c != nil {
 		t.Errorf("a logout that failed set the session cookie: %s", c)
 	}
 	req = httptest.NewRequestWithContext(t.Context(), http.MethodGet, "/", nil)
 	req.AddCookie(cookie)
 	rec = httptest.NewRecorder()
 	srv.ServeHTTP(rec, req)
 	if !strings.Contains(rec.Body.String(), generatorForm) {
 		t.Error("a logout that failed ended the session")
 	}
 }
 // TestGeneratePost_NoSession_RedirectsToLogin verifies that POST /generate
 // with a valid CSRF token but no login session answers 303 to / and makes no
 // URL.
@@ -320,7 +222,7 @@ func TestGeneratePost_URLServesImage(t *testing.T) {
 		sourceURLField: {"https://" + signedHost + photoPath},
 		widthField:     {"50"},
 		heightField:    {"50"},
-		formatField:    {string(imagerequest.FormatJPEG)},
+		formatField:    {string(imgcache.FormatJPEG)},
 	})
 	if rec.Code != http.StatusOK {
@@ -353,7 +255,7 @@ func TestGeneratePost_URLWithTTLExpires(t *testing.T) {
 		sourceURLField: {"https://" + signedHost + photoPath},
 		widthField:     {"50"},
 		heightField:    {"50"},
-		formatField:    {string(imagerequest.FormatJPEG)},
+		formatField:    {string(imgcache.FormatJPEG)},
 		ttlField:       {"1"},
 	})
@@ -1,39 +0,0 @@
 package handlers
 import (
 	"fmt"
 	"log/slog"
 	"net/http"
 	"net/http/httptest"
 	"strings"
 	"testing"
 	"sneak.berlin/go/pixa/internal/imageprocessor"
 	"sneak.berlin/go/pixa/internal/imagerequest"
 )
 // TestAVIFOutputTooLargeAnswers400 checks that respondImageError, which
 // answers the errors of both image routes, answers 400 naming the AVIF pixel
 // limit when the image processor refuses an AVIF output above it, wrapped as
 // the service wraps it. The request's source only goes into a log line, so it
 // is left empty.
 func TestAVIFOutputTooLargeAnswers400(t *testing.T) {
 	t.Parallel()
 	h := &Handlers{log: slog.New(slog.DiscardHandler)}
 	err := fmt.Errorf("image processing failed: %w: 4097x4096",
 		imageprocessor.ErrAVIFOutputTooLarge)
 	wantBody := fmt.Sprintf("above %d pixels", imageprocessor.MaxAVIFOutputPixels)
 	rec := httptest.NewRecorder()
 	h.respondImageError(rec, &imagerequest.Request{}, err)
 	t.Logf("status = %d, body = %q", rec.Code, rec.Body.String())
 	if rec.Code != http.StatusBadRequest {
 		t.Errorf("status = %d, want %d", rec.Code, http.StatusBadRequest)
 	}
 	if !strings.Contains(rec.Body.String(), wantBody) {
 		t.Errorf("body = %q, want it to say %q", rec.Body.String(), wantBody)
 	}
 }
@@ -11,7 +11,6 @@ import (
 	"sneak.berlin/go/pixa/internal/config"
 	"sneak.berlin/go/pixa/internal/encurl"
 	"sneak.berlin/go/pixa/internal/seal"
 	"sneak.berlin/go/pixa/internal/session"
 )
@@ -33,17 +32,27 @@ func newBodyLimitTestRouter(
 	cfg := &config.Config{SigningKey: testSigningKey, Debug: true}
-	keys, err := seal.DeriveKeys(testSigningKey)
+	sessMgr, err := session.NewManager(testSigningKey)
 	if err != nil {
-		t.Fatalf("seal.DeriveKeys() error = %v", err)
+		t.Fatalf("session.NewManager() error = %v", err)
 	}
 	encGen, err := encurl.NewGenerator(testSigningKey)
 	if err != nil {
 		t.Fatalf("encurl.NewGenerator() error = %v", err)
 	}
 	protect, err := newCSRFProtect(testSigningKey, cfg.Debug)
 	if err != nil {
 		t.Fatalf("newCSRFProtect() error = %v", err)
 	}
 	h := &Handlers{
 		log:         slog.New(slog.DiscardHandler),
 		config:      cfg,
-		sessMgr:     session.NewManager(keys.SessionHashKey, keys.SessionBlockKey),
+		sessMgr:     sessMgr,
-		encGen:      encurl.NewGenerator(keys.EncryptedURLKey),
+		encGen:      encGen,
-		csrfProtect: newCSRFProtect(keys.CSRFKey, cfg.Debug, slog.New(slog.DiscardHandler)),
+		csrfProtect: protect,
 	}
 	r := chi.NewRouter()
@@ -1,278 +0,0 @@
 package handlers
 import (
 	"bytes"
 	"context"
 	"database/sql"
 	"database/sql/driver"
 	"image"
 	"image/jpeg"
 	"log/slog"
 	"net/http"
 	"net/http/httptest"
 	"path/filepath"
 	"sync/atomic"
 	"testing"
 	"testing/fstest"
 	"time"
 	"github.com/go-chi/chi/v5"
 	"github.com/prometheus/client_golang/prometheus"
 	"sneak.berlin/go/pixa/internal/allowlist"
 	"sneak.berlin/go/pixa/internal/database"
 	"sneak.berlin/go/pixa/internal/encurl"
 	"sneak.berlin/go/pixa/internal/imageprocessor"
 	"sneak.berlin/go/pixa/internal/imageproxy"
 	"sneak.berlin/go/pixa/internal/imagerequest"
 	"sneak.berlin/go/pixa/internal/imgcache"
 	"sneak.berlin/go/pixa/internal/seal"
 	"sneak.berlin/go/pixa/internal/signature"
 )
 // countingHost is the allowlisted host whose photoPath the server of
 // newCountingDatabaseServer serves.
 const countingHost = "counting.example.com"
 // countingConnector opens connections to the SQLite database file name with
 // sqliteDriver, each one counting in statements the statements run on it.
 type countingConnector struct {
 	sqliteDriver driver.Driver
 	name         string
 	statements   *atomic.Int64
 }
 func (c countingConnector) Connect(context.Context) (driver.Conn, error) {
 	conn, err := c.sqliteDriver.Open(c.name)
 	if err != nil {
 		return nil, err
 	}
 	return countingConn{Conn: conn, statements: c.statements}, nil
 }
 func (c countingConnector) Driver() driver.Driver {
 	return c.sqliteDriver
 }
 // countingConn counts the statements run on its connection. It has only the
 // methods of driver.Conn, so database/sql prepares every query and every
 // other statement with Prepare, which counts it.
 type countingConn struct {
 	driver.Conn
 	statements *atomic.Int64
 }
 func (c countingConn) Prepare(query string) (driver.Stmt, error) {
 	c.statements.Add(1)
 	return c.Conn.Prepare(query)
 }
 // newCountingDatabase returns a database with pixa's schema, in a file of
 // its own and with one connection, and the count of the statements run on
 // it once the schema is in place.
 func newCountingDatabase(tb testing.TB) (*sql.DB, *atomic.Int64) {
 	tb.Helper()
 	path := filepath.Join(tb.TempDir(), "state.sqlite3")
 	schemaDB, err := sql.Open("sqlite", path)
 	if err != nil {
 		tb.Fatalf("opening the database: %v", err)
 	}
 	defer func() { _ = schemaDB.Close() }()
 	err = database.ApplyMigrations(tb.Context(), schemaDB, nil)
 	if err != nil {
 		tb.Fatalf("applying the migrations: %v", err)
 	}
 	statements := new(atomic.Int64)
 	db := sql.OpenDB(countingConnector{
 		sqliteDriver: schemaDB.Driver(),
 		name:         path,
 		statements:   statements,
 	})
 	db.SetMaxOpenConns(1)
 	tb.Cleanup(func() { _ = db.Close() })
 	return db, statements
 }
 // newCountingDatabaseServer returns a router for both image routes whose
 // image cache uses newCountingDatabase, the count of the statements run on
 // that database, and a URL on each route for a different image of
 // photoPath on countingHost. Nothing writes the cache's access times in the
 // background, so every statement counted comes from a request.
 func newCountingDatabaseServer(
 	tb testing.TB,
 ) (http.Handler, *atomic.Int64, []string) {
 	tb.Helper()
 	db, statements := newCountingDatabase(tb)
 	var photo bytes.Buffer
 	err := jpeg.Encode(&photo, image.NewRGBA(image.Rect(0, 0, 100, 100)), nil)
 	if err != nil {
 		tb.Fatalf("encoding the photo: %v", err)
 	}
 	cache, err := imgcache.NewCache(db, imgcache.Config{
 		StateDir:    tb.TempDir(),
 		NegativeTTL: 5 * time.Minute,
 		MaxBytes:    1 << 30,
 	}, prometheus.NewRegistry())
 	if err != nil {
 		tb.Fatalf("imgcache.NewCache() error = %v", err)
 	}
 	svc, err := imageproxy.New(&imageproxy.Config{
 		Cache: cache,
 		Fetcher: newMockFetcher(fstest.MapFS{
 			countingHost + photoPath: &fstest.MapFile{Data: photo.Bytes()},
 		}),
 		Processor: imageprocessor.New(imageprocessor.Params{
 			MaxInputBytes:           50 << 20,
 			MaxConcurrentProcessing: 2,
 		}),
 		MaxResponseSize: 50 << 20,
 		Logger:          slog.New(slog.DiscardHandler),
 	}, prometheus.NewRegistry())
 	if err != nil {
 		tb.Fatalf("imageproxy.New() error = %v", err)
 	}
 	keys, err := seal.DeriveKeys(testSigningKey)
 	if err != nil {
 		tb.Fatalf("seal.DeriveKeys() error = %v", err)
 	}
 	encGen := encurl.NewGenerator(keys.EncryptedURLKey)
 	token, err := encGen.Generate(&imagerequest.Request{
 		Source: imagerequest.Source{Host: countingHost, Path: photoPath},
 		Transform: imagerequest.Transform{
 			Size:    imagerequest.Size{Width: 40, Height: 40},
 			Format:  imagerequest.FormatJPEG,
 			Quality: 85,
 			FitMode: imagerequest.FitCover,
 		},
 	}, time.Time{})
 	if err != nil {
 		tb.Fatalf("encGen.Generate() error = %v", err)
 	}
 	h := &Handlers{
 		log:       slog.New(slog.DiscardHandler),
 		imgSvc:    svc,
 		encGen:    encGen,
 		signer:    signature.New(testSigningKey),
 		allowlist: allowlist.New([]string{countingHost}),
 	}
 	r := chi.NewRouter()
 	r.Get("/v1/image/*", h.HandleImage())
 	r.Get("/v1/e/{token}/*", h.HandleImageEnc())
 	return r, statements, []string{
 		"/v1/image/" + countingHost + photoPath + "/50x50.jpeg",
 		"/v1/e/" + token + "/img.jpg",
 	}
 }
 // serveImage sends srv a GET for target and returns the response, failing
 // the test unless it is a 200 with an image.
 func serveImage(
 	tb testing.TB, srv http.Handler, target string,
 ) *httptest.ResponseRecorder {
 	tb.Helper()
 	rec := httptest.NewRecorder()
 	srv.ServeHTTP(rec,
 		httptest.NewRequestWithContext(tb.Context(), http.MethodGet, target, nil))
 	if rec.Code != http.StatusOK || rec.Body.Len() == 0 {
 		tb.Errorf("GET %s: %d with %d bytes, want 200 with an image",
 			target, rec.Code, rec.Body.Len())
 	}
 	return rec
 }
 // TestImageRoutes_CacheHitsMakeNoDatabaseCall serves an image on each image
 // route once, which makes and caches it, then serves it again from the cache.
 // Serving those cache hits must run no statement on the database.
 func TestImageRoutes_CacheHitsMakeNoDatabaseCall(t *testing.T) {
 	t.Parallel()
 	srv, statements, targets := newCountingDatabaseServer(t)
 	for _, target := range targets {
 		before := statements.Load()
 		serveImage(t, srv, target)
 		afterMiss := statements.Load()
 		t.Logf("GET %s, a miss: %d statements", target, afterMiss-before)
 		if afterMiss == before {
 			t.Fatalf("GET %s, a miss: no statement counted, want some", target)
 		}
 		for range 3 {
 			rec := serveImage(t, srv, target)
 			cacheStatus := rec.Header().Get("X-Pixa-Cache")
 			if cacheStatus != string(imageproxy.CacheHit) {
 				t.Errorf("GET %s: X-Pixa-Cache = %q, want %s",
 					target, cacheStatus, imageproxy.CacheHit)
 			}
 		}
 		if hitStatements := statements.Load() - afterMiss; hitStatements != 0 {
 			t.Errorf("GET %s: 3 cache hits ran %d statements, want 0",
 				target, hitStatements)
 		}
 	}
 }
 // BenchmarkHandleImage_CacheHits serves one cached image through the
 // /v1/image/ route from b.RunParallel's goroutines, and reports the cache
 // hits served per second. It fails if serving them ran any statement on the
 // database. script/bench runs it.
 func BenchmarkHandleImage_CacheHits(b *testing.B) {
 	srv, statements, targets := newCountingDatabaseServer(b)
 	target := targets[0]
 	serveImage(b, srv, target)
 	before := statements.Load()
 	b.ResetTimer()
 	b.RunParallel(func(pb *testing.PB) {
 		for pb.Next() {
 			rec := serveImage(b, srv, target)
 			cacheStatus := rec.Header().Get("X-Pixa-Cache")
 			if cacheStatus != string(imageproxy.CacheHit) {
 				b.Errorf("GET %s: X-Pixa-Cache = %q, want %s",
 					target, cacheStatus, imageproxy.CacheHit)
 				return
 			}
 		}
 	})
 	b.ReportMetric(float64(b.N)/b.Elapsed().Seconds(), "hits/s")
 	if hitStatements := statements.Load() - before; hitStatements != 0 {
 		b.Fatalf("%d cache hits ran %d statements, want 0", b.N, hitStatements)
 	}
 }
@@ -0,0 +1,147 @@
 package handlers
 import (
 	"os"
 	"path/filepath"
 	"testing"
 	"go.uber.org/fx/fxtest"
 	"sneak.berlin/go/pixa/internal/config"
 	"sneak.berlin/go/pixa/internal/database"
 	"sneak.berlin/go/pixa/internal/globals"
 	"sneak.berlin/go/pixa/internal/logger"
 )
 // TestNewCacheConfigFromCacheMaxBytes checks the cache configuration
 // built from cache_max_bytes: omitted, the cache works out the default
 // limit; 0 turns the disk cache off; a positive value is the limit,
 // unchanged.
 func TestNewCacheConfigFromCacheMaxBytes(t *testing.T) {
 	t.Parallel()
 	const oneGiB = 1 << 30
 	cases := []struct {
 		name                   string
 		cacheMaxBytes          int64
 		cacheMaxBytesExplicit  bool
 		wantMaxBytes           int64
 		wantUseDefaultMaxBytes bool
 		wantDisableDiskCache   bool
 	}{
 		{
 			name:                   "cache_max_bytes omitted",
 			cacheMaxBytes:          0,
 			cacheMaxBytesExplicit:  false,
 			wantMaxBytes:           0,
 			wantUseDefaultMaxBytes: true,
 			wantDisableDiskCache:   false,
 		},
 		{
 			name:                   "cache_max_bytes: 0",
 			cacheMaxBytes:          0,
 			cacheMaxBytesExplicit:  true,
 			wantMaxBytes:           0,
 			wantUseDefaultMaxBytes: false,
 			wantDisableDiskCache:   true,
 		},
 		{
 			name:                   "cache_max_bytes: 1 GiB",
 			cacheMaxBytes:          oneGiB,
 			cacheMaxBytesExplicit:  true,
 			wantMaxBytes:           oneGiB,
 			wantUseDefaultMaxBytes: false,
 			wantDisableDiskCache:   false,
 		},
 	}
 	for _, tc := range cases {
 		t.Run(tc.name, func(t *testing.T) {
 			t.Parallel()
 			cfg := &config.Config{
 				CacheMaxBytes:         tc.cacheMaxBytes,
 				CacheMaxBytesExplicit: tc.cacheMaxBytesExplicit,
 			}
 			got := newCacheConfig(cfg, nil)
 			t.Logf("MaxBytes = %d, UseDefaultMaxBytes = %v, DisableDiskCache = %v",
 				got.MaxBytes, got.UseDefaultMaxBytes, got.DisableDiskCache)
 			if got.MaxBytes != tc.wantMaxBytes {
 				t.Errorf("MaxBytes = %d, want %d", got.MaxBytes, tc.wantMaxBytes)
 			}
 			if got.UseDefaultMaxBytes != tc.wantUseDefaultMaxBytes {
 				t.Errorf("UseDefaultMaxBytes = %v, want %v",
 					got.UseDefaultMaxBytes, tc.wantUseDefaultMaxBytes)
 			}
 			if got.DisableDiskCache != tc.wantDisableDiskCache {
 				t.Errorf("DisableDiskCache = %v, want %v",
 					got.DisableDiskCache, tc.wantDisableDiskCache)
 			}
 		})
 	}
 }
 // TestDiskCacheOffOnlyForExplicitZeroCacheMaxBytes starts the handlers
 // once with cache_max_bytes omitted and once with cache_max_bytes: 0,
 // and checks by whether the cache directories were created that the
 // disk cache is on in the first case and off in the second.
 func TestDiskCacheOffOnlyForExplicitZeroCacheMaxBytes(t *testing.T) {
 	t.Parallel()
 	cases := []struct {
 		name                  string
 		cacheMaxBytesExplicit bool
 		wantDiskCache         bool
 	}{
 		{name: "cache_max_bytes omitted", cacheMaxBytesExplicit: false, wantDiskCache: true},
 		{name: "cache_max_bytes: 0", cacheMaxBytesExplicit: true, wantDiskCache: false},
 	}
 	for _, tc := range cases {
 		t.Run(tc.name, func(t *testing.T) {
 			t.Parallel()
 			stateDir := t.TempDir()
 			cfg := &config.Config{
 				SigningKey:            testSigningKey,
 				StateDir:              stateDir,
 				DBURL:                 "file:" + filepath.Join(stateDir, "state.sqlite3"),
 				CacheMaxBytes:         0,
 				CacheMaxBytesExplicit: tc.cacheMaxBytesExplicit,
 			}
 			lc := fxtest.NewLifecycle(t)
 			log, err := logger.New(lc, logger.Params{Globals: &globals.Globals{}})
 			if err != nil {
 				t.Fatalf("logger.New() error = %v", err)
 			}
 			db, err := database.New(lc, database.Params{Logger: log, Config: cfg})
 			if err != nil {
 				t.Fatalf("database.New() error = %v", err)
 			}
 			_, err = New(lc, Params{Logger: log, Database: db, Config: cfg})
 			if err != nil {
 				t.Fatalf("New() error = %v", err)
 			}
 			lc.RequireStart()
 			t.Cleanup(lc.RequireStop)
 			_, err = os.Stat(filepath.Join(stateDir, "cache", "variants"))
 			gotDiskCache := err == nil
 			if gotDiskCache != tc.wantDiskCache {
 				t.Errorf("cache directories created = %v, want %v",
 					gotDiskCache, tc.wantDiskCache)
 			}
 		})
 	}
 }
@@ -1,177 +0,0 @@
 package handlers
 import (
 	"bytes"
 	"context"
 	"encoding/json"
 	"log/slog"
 	"net/http"
 	"net/http/httptest"
 	"slices"
 	"testing"
 	"time"
 	"github.com/go-chi/chi/v5/middleware"
 	"sneak.berlin/go/pixa/internal/httpfetcher"
 	"sneak.berlin/go/pixa/internal/imagerequest"
 )
 // heldFetcher sends on started when a fetch begins, and holds the fetch until
 // release is closed. It then fails the fetch as an upstream error.
 type heldFetcher struct {
 	started chan struct{}
 	release chan struct{}
 }
 // Fetch sends on f.started, waits for f.release to be closed, and returns
 // httpfetcher.ErrUpstreamError.
 func (f heldFetcher) Fetch(
 	context.Context, imagerequest.Source, string, string,
 ) (*httpfetcher.FetchResult, error) {
 	f.started <- struct{}{}
 	<-f.release
 	return nil, httpfetcher.ErrUpstreamError
 }
 // readLogLines decodes the JSON log lines in logs.
 func readLogLines(t *testing.T, logs *bytes.Buffer) []map[string]any {
 	t.Helper()
 	t.Logf("logged:\n%s", logs.String())
 	var lines []map[string]any
 	dec := json.NewDecoder(logs)
 	for dec.More() {
 		var line map[string]any
 		err := dec.Decode(&line)
 		if err != nil {
 			t.Fatalf("decoding log line: %v", err)
 		}
 		lines = append(lines, line)
 	}
 	return lines
 }
 // TestImageRoutes_ClientGoneWhileWaitingAnswers499 checks that both image
 // routes answer 499 to a request whose client goes away while it waits for an
 // image another request is making. A first request's fetch is held, so the
 // image is being made, and a second request for the same image waits for it
 // until its client goes away. The second request must be logged once at info
 // level with its request ID and the source host and path. Nothing may be
 // logged at error level.
 func TestImageRoutes_ClientGoneWhileWaitingAnswers499(t *testing.T) {
 	t.Parallel()
 	const requestID = "test-request-id"
 	for route, imageURL := range photoURLsByRoute() {
 		t.Run(route, func(t *testing.T) {
 			t.Parallel()
 			var logs bytes.Buffer
 			fetcher := heldFetcher{started: make(chan struct{}), release: make(chan struct{})}
 			h, routes := newRoutesFetchingThrough(t, fetcher,
 				slog.New(slog.NewJSONHandler(&logs, nil)))
 			target := imageURL(t, h)
 			firstDone := make(chan struct{})
 			go func() {
 				defer close(firstDone)
 				sendGet(t, routes, target)
 			}()
 			<-fetcher.started
 			ctx, cancel := context.WithCancel(context.WithValue(t.Context(),
 				middleware.RequestIDKey, requestID))
 			rec := httptest.NewRecorder()
 			secondDone := make(chan struct{})
 			go func() {
 				defer close(secondDone)
 				routes.ServeHTTP(rec, httptest.NewRequestWithContext(
 					ctx, http.MethodGet, target, nil))
 			}()
 			// Give the second request time to start waiting for the first
 			// request's image. The fetch is still held, so the second request
 			// can end only because its client went away
 			time.Sleep(100 * time.Millisecond)
 			cancel()
 			<-secondDone
 			close(fetcher.release)
 			<-firstDone
 			if rec.Code != 499 {
 				t.Errorf("status = %d, want 499", rec.Code)
 			}
 			var clientGoneLines int
 			for _, line := range readLogLines(t, &logs) {
 				if line["level"] == slog.LevelError.String() {
 					t.Errorf("logged at error level: %v", line["msg"])
 				}
 				if line["level"] == slog.LevelInfo.String() &&
 					line["msg"] == "client went away before the image was ready" &&
 					line["request_id"] == requestID &&
 					line["host"] == signedHost &&
 					line["path"] == photoPath {
 					clientGoneLines++
 				}
 			}
 			if clientGoneLines != 1 {
 				t.Errorf("info line naming the request logged %d times, want 1",
 					clientGoneLines)
 			}
 		})
 	}
 }
 // TestImageRoutes_CanceledWithLiveRequestAnswers500 checks that both image
 // routes answer 500, logged as "failed to get image" at error level, for an
 // image service error that wraps context.Canceled while the request's own
 // context is live. Its client has not gone away, so the cancellation is
 // pixa's own failure.
 func TestImageRoutes_CanceledWithLiveRequestAnswers500(t *testing.T) {
 	t.Parallel()
 	for route, imageURL := range photoURLsByRoute() {
 		t.Run(route, func(t *testing.T) {
 			t.Parallel()
 			var logs bytes.Buffer
 			h, routes := newRoutesFetchingThrough(t,
 				failingFetcher{err: context.Canceled},
 				slog.New(slog.NewJSONHandler(&logs, nil)))
 			rec := sendGet(t, routes, imageURL(t, h))
 			if rec.Code != http.StatusInternalServerError {
 				t.Errorf("status = %d, want %d",
 					rec.Code, http.StatusInternalServerError)
 			}
 			if !slices.ContainsFunc(readLogLines(t, &logs),
 				func(line map[string]any) bool {
 					return line["level"] == slog.LevelError.String() &&
 						line["msg"] == "failed to get image"
 				}) {
 				t.Error(`no "failed to get image" line logged at error level`)
 			}
 		})
 	}
 }
@@ -1,43 +1,23 @@
 package handlers
 import (
 	"bytes"
 	"errors"
 	"html/template"
 	"log/slog"
 	"net/http"
 	"net/url"
 	"github.com/go-chi/chi/v5/middleware"
 	"github.com/gorilla/csrf"
 	"sneak.berlin/go/pixa/internal/seal"
 	"sneak.berlin/go/pixa/internal/templates"
 )
-// The causes the form-refused page names, each with what to do about it.
+// csrfKeySalt provides domain separation for the CSRF authentication key,
-const (
+// derived from the signing key so tokens survive restarts without extra
-	causePlainHTTP = "This page was opened over plain HTTP while debug is " +
+// configuration and never reuse the session or encrypted-URL key material.
-		"off. Open it over HTTPS, or turn debug on to use plain HTTP on " +
+const csrfKeySalt = "pixa-csrf-v1"
 		"your own machine."
 	causeHTTPSWithDebug = "This page was opened over HTTPS while debug is " +
 		"on. Turn debug off, or open the page over plain HTTP."
 	causeOtherHost = "The form was sent from another host than the one in " +
 		"the request's Host header. A reverse proxy in front of pixa must " +
 		"pass the Host header on unchanged."
 	causeNoReferer = "The browser sent neither an Origin nor a Referer " +
 		"header, and over HTTPS pixa needs one to check where the form " +
 		"came from. Let the browser send the Referer header to this site."
 	causeStaleToken = "The form token is missing or out of date. Reload " +
 		"the page and submit the form again."
 )
 // newCSRFProtect builds the CSRF-protection middleware for the
 // state-mutating HTML form routes. The token lives in its own cookie,
 // independent of the session cookie, so it also protects the login POST
-// where no session exists yet (login CSRF). key signs that cookie. A
+// where no session exists yet (login CSRF).
 // refused form is answered by the handler that handleFormRefused returns.
 // log gets a warning with the library's reason, such as "origin invalid".
 //
 // When plaintext is true (local HTTP development), requests are marked
 // plaintext so the library neither demands an https Referer nor sets a
@@ -45,18 +25,22 @@ const (
 // service runs behind a TLS-terminating proxy, so plaintext is false and
 // the library enforces its https Referer origin check.
 func newCSRFProtect(
-	key [seal.KeySize]byte, plaintext bool, log *slog.Logger,
+	signingKey string, plaintext bool,
-) func(http.Handler) http.Handler {
+) (func(http.Handler) http.Handler, error) {
 	key, err := seal.DeriveKey([]byte(signingKey), csrfKeySalt)
 	if err != nil {
 		return nil, err
 	}
 	protect := csrf.Protect(
 		key[:],
 		csrf.Path("/"),
 		csrf.Secure(!plaintext),
 		csrf.SameSite(csrf.SameSiteStrictMode),
 		csrf.ErrorHandler(handleFormRefused(plaintext, log)),
 	)
 	if !plaintext {
-		return protect
+		return protect, nil
 	}
 	return func(next http.Handler) http.Handler {
@@ -65,85 +49,7 @@ func newCSRFProtect(
 		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 			protected.ServeHTTP(w, csrf.PlaintextHTTPRequest(r))
 		})
-	}
+	}, nil
 }
 // handleFormRefused returns the handler the CSRF middleware calls when it
 // refuses a request. It logs the library's reason with the request ID and
 // answers 403 with a page naming the cause and what to do. A reason that is
 // not a refusal, such as a failure to make a token, answers 500.
 func handleFormRefused(plaintext bool, log *slog.Logger) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		reason := csrf.FailureReason(r)
 		requestID := middleware.GetReqID(r.Context())
 		cause := formRefusedCause(r, reason, plaintext)
 		if cause == "" {
 			log.Error("CSRF middleware failed",
 				"request_id", requestID, "error", reason)
 			http.Error(w, "Internal server error",
 				http.StatusInternalServerError)
 			return
 		}
 		log.Warn("form refused", "request_id", requestID, "reason", reason)
 		var page bytes.Buffer
 		err := templates.Render(&page, "form_refused.html",
 			struct{ Cause string }{Cause: cause})
 		if err != nil {
 			log.Error("failed to render form refused template", "error", err)
 			http.Error(w, "Internal server error",
 				http.StatusInternalServerError)
 			return
 		}
 		w.Header().Set("Content-Type", "text/html; charset=utf-8")
 		w.WriteHeader(http.StatusForbidden)
 		_, err = page.WriteTo(w)
 		if err != nil {
 			log.Error("failed to write form refused page", "error", err)
 		}
 	})
 }
 // formRefusedCause returns the cause the form-refused page names for the
 // CSRF middleware's reason, or "" when the reason is not a refusal.
 func formRefusedCause(r *http.Request, reason error, plaintext bool) string {
 	switch {
 	case errors.Is(reason, csrf.ErrNoToken), errors.Is(reason, csrf.ErrBadToken):
 		return causeStaleToken
 	case errors.Is(reason, csrf.ErrNoReferer):
 		return causeNoReferer
 	case errors.Is(reason, csrf.ErrBadOrigin):
 		return pageAddressCause(r.Header.Get("Origin"), r.Host, plaintext)
 	case errors.Is(reason, csrf.ErrBadReferer):
 		return pageAddressCause(r.Referer(), r.Host, plaintext)
 	default:
 		return ""
 	}
 }
 // pageAddressCause returns the cause for a form whose page address, the
 // Origin or Referer header, the CSRF middleware refused. The middleware
 // expects the request's own host, with https when plaintext is false and
 // http when it is true. So on the request's own host, only the scheme was
 // wrong.
 func pageAddressCause(pageAddress, host string, plaintext bool) string {
 	page, err := url.Parse(pageAddress)
 	if err != nil || page.Host != host {
 		return causeOtherHost
 	}
 	if plaintext {
 		return causeHTTPSWithDebug
 	}
 	return causePlainHTTP
 }
 // CSRF returns the CSRF-protection middleware for the login and generator
@@ -1,205 +0,0 @@
 package handlers
 import (
 	"bytes"
 	"context"
 	"encoding/json"
 	"html/template"
 	"log/slog"
 	"net/http"
 	"net/http/httptest"
 	"net/url"
 	"strings"
 	"testing"
 	"github.com/go-chi/chi/v5/middleware"
 	"github.com/gorilla/csrf"
 	"sneak.berlin/go/pixa/internal/seal"
 )
 // refusedFormRequestID is the request ID of the requests postRefusedForm
 // sends, which the warning for a refused form must carry.
 const refusedFormRequestID = "test-request-id"
 // TestFormRefusedNamesCause verifies that a form the CSRF middleware refuses
 // answers 403 with a page naming the cause, and logs a warning with the
 // request ID and the middleware's reason.
 func TestFormRefusedNamesCause(t *testing.T) {
 	t.Parallel()
 	tests := []struct {
 		name       string
 		debug      bool
 		origin     string
 		referer    string
 		wantCause  string
 		wantReason error
 	}{
 		{
 			name:       "plain HTTP origin with debug off",
 			origin:     "http://example.com",
 			wantCause:  causePlainHTTP,
 			wantReason: csrf.ErrBadOrigin,
 		},
 		{
 			name:       "plain HTTP referer with debug off",
 			referer:    "http://example.com/",
 			wantCause:  causePlainHTTP,
 			wantReason: csrf.ErrBadReferer,
 		},
 		{
 			name:       "origin on another host",
 			origin:     "https://proxy.example.net",
 			wantCause:  causeOtherHost,
 			wantReason: csrf.ErrBadOrigin,
 		},
 		{
 			name:       "referer on another host",
 			referer:    "https://proxy.example.net/",
 			wantCause:  causeOtherHost,
 			wantReason: csrf.ErrBadReferer,
 		},
 		{
 			name:       "HTTPS origin with debug on",
 			debug:      true,
 			origin:     "https://example.com",
 			wantCause:  causeHTTPSWithDebug,
 			wantReason: csrf.ErrBadOrigin,
 		},
 		{
 			name:       "no origin or referer with debug off",
 			wantCause:  causeNoReferer,
 			wantReason: csrf.ErrNoReferer,
 		},
 		{
 			name:       "missing token",
 			debug:      true,
 			origin:     "http://example.com",
 			wantCause:  causeStaleToken,
 			wantReason: csrf.ErrNoToken,
 		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			rec, logLine := postRefusedForm(t, tt.debug, tt.origin, tt.referer,
 				nil, "")
 			checkFormRefused(t, rec, logLine, tt.wantCause, tt.wantReason)
 		})
 	}
 }
 // TestFormRefusedNamesCauseForForeignToken verifies that a form whose token
 // does not match its CSRF cookie answers 403 with a page naming
 // causeStaleToken, and logs a warning with the request ID and the
 // middleware's reason.
 func TestFormRefusedNamesCauseForForeignToken(t *testing.T) {
 	t.Parallel()
 	// The router and postRefusedForm derive their CSRF key from
 	// testSigningKey, so cookiesA is valid there and only tokenB is wrong.
 	_, router := newCSRFTestRouter(t)
 	cookiesA, _ := csrfCredentials(t, router, nil)
 	_, tokenB := csrfCredentials(t, router, nil)
 	rec, logLine := postRefusedForm(t, true, "http://example.com", "",
 		cookiesA, tokenB)
 	checkFormRefused(t, rec, logLine, causeStaleToken, csrf.ErrBadToken)
 }
 // postRefusedForm sends a POST with the given cookies to the CSRF
 // middleware built for debug. It adds the form token and the Origin and
 // Referer headers when they are not empty. It returns the response and the
 // one JSON log line the middleware wrote.
 func postRefusedForm(
 	t *testing.T, debug bool, origin, referer string,
 	cookies []*http.Cookie, token string,
 ) (*httptest.ResponseRecorder, map[string]any) {
 	t.Helper()
 	keys, err := seal.DeriveKeys(testSigningKey)
 	if err != nil {
 		t.Fatalf("seal.DeriveKeys() error = %v", err)
 	}
 	var logs bytes.Buffer
 	log := slog.New(slog.NewJSONHandler(&logs, nil))
 	reached := http.HandlerFunc(func(_ http.ResponseWriter, _ *http.Request) {
 		t.Error("the refused form reached the handler behind the middleware")
 	})
 	srv := newCSRFProtect(keys.CSRFKey, debug, log)(reached)
 	form := url.Values{loginKeyField: {"x"}}
 	if token != "" {
 		form.Set(csrfTokenField, token)
 	}
 	ctx := context.WithValue(context.Background(),
 		middleware.RequestIDKey, refusedFormRequestID)
 	req := httptest.NewRequestWithContext(ctx, http.MethodPost,
 		"http://example.com/", strings.NewReader(form.Encode()))
 	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
 	for _, c := range cookies {
 		req.AddCookie(c)
 	}
 	if origin != "" {
 		req.Header.Set("Origin", origin)
 	}
 	if referer != "" {
 		req.Header.Set("Referer", referer)
 	}
 	rec := httptest.NewRecorder()
 	srv.ServeHTTP(rec, req)
 	var logLine map[string]any
 	err = json.Unmarshal(logs.Bytes(), &logLine)
 	if err != nil {
 		t.Fatalf("decoding log line %q: %v", logs.String(), err)
 	}
 	return rec, logLine
 }
 // checkFormRefused checks that rec is a 403 page naming wantCause and that
 // logLine is a warning carrying the request ID and wantReason.
 func checkFormRefused(
 	t *testing.T, rec *httptest.ResponseRecorder, logLine map[string]any,
 	wantCause string, wantReason error,
 ) {
 	t.Helper()
 	if rec.Code != http.StatusForbidden {
 		t.Errorf("status = %d, want %d", rec.Code, http.StatusForbidden)
 	}
 	body := rec.Body.String()
 	t.Logf("body: %s", body)
 	if !strings.Contains(body, template.HTMLEscapeString(wantCause)) {
 		t.Errorf("page does not name the cause %q", wantCause)
 	}
 	t.Logf("log line: %v", logLine)
 	if logLine["level"] != "WARN" || logLine["msg"] != "form refused" {
 		t.Errorf("log line = %v, want a WARN \"form refused\"", logLine)
 	}
 	if logLine["request_id"] != refusedFormRequestID {
 		t.Errorf("logged request_id = %v, want %q",
 			logLine["request_id"], refusedFormRequestID)
 	}
 	if logLine["reason"] != wantReason.Error() {
 		t.Errorf("logged reason = %v, want %q", logLine["reason"], wantReason)
 	}
 }
@@ -0,0 +1,61 @@
 package handlers
 import (
 	"net/http"
 	"net/netip"
 	"path/filepath"
 	"testing"
 	"time"
 	"github.com/go-chi/chi/v5"
 	"go.uber.org/fx"
 	"go.uber.org/fx/fxtest"
 	"sneak.berlin/go/pixa/internal/config"
 	"sneak.berlin/go/pixa/internal/database"
 	"sneak.berlin/go/pixa/internal/globals"
 	"sneak.berlin/go/pixa/internal/healthcheck"
 	"sneak.berlin/go/pixa/internal/logger"
 )
 // TestHandlersBuildTheirOwnFetcherWhenNoneIsProvided builds the handlers as
 // pixad does, in an fx app that provides no fetcher, and requests an image
 // from 192.0.2.10, which is on the allowlist and in blocked_networks. The URL
 // check accepts that address; only the dialer that refuses internal
 // addresses checks blocked_networks, so the answer is 403 only if the
 // fetcher the handlers build from the config connects with that dialer. Any
 // other dialer would try to connect until the upstream fetch timeout, which
 // is short so that the test then fails quickly.
 func TestHandlersBuildTheirOwnFetcherWhenNoneIsProvided(t *testing.T) {
 	t.Parallel()
 	const host = "192.0.2.10"
 	stateDir := t.TempDir()
 	cfg := &config.Config{
 		SigningKey:           testSigningKey,
 		StateDir:             stateDir,
 		DBURL:                "file:" + filepath.Join(stateDir, "state.sqlite3"),
 		AllowlistHosts:       []string{host},
 		BlockedNetworks:      []netip.Prefix{netip.MustParsePrefix("192.0.2.0/24")},
 		UpstreamFetchTimeout: 2 * time.Second,
 		// With no connection slots, the fetch would fail before dialing.
 		UpstreamConnections: config.DefaultUpstreamConnections,
 	}
 	var h *Handlers
 	app := fxtest.New(t,
 		fx.Supply(cfg),
 		fx.Provide(globals.New, logger.New, database.New, healthcheck.New, New),
 		fx.Populate(&h),
 	)
 	app.RequireStart()
 	t.Cleanup(app.RequireStop)
 	r := chi.NewRouter()
 	r.Get("/v1/image/*", h.HandleImage())
 	rec := sendGet(t, r, photoURL(host))
 	checkErrorBody(t, rec, http.StatusForbidden, "forbidden")
 }
@@ -1,203 +0,0 @@
 package handlers
 import (
 	"bytes"
 	"encoding/json"
 	"image/color"
 	"log/slog"
 	"net/http"
 	"slices"
 	"testing"
 	"testing/fstest"
 	"time"
 	"github.com/go-chi/chi/v5"
 	"github.com/prometheus/client_golang/prometheus"
 	"sneak.berlin/go/pixa/internal/allowlist"
 	"sneak.berlin/go/pixa/internal/encurl"
 	"sneak.berlin/go/pixa/internal/httpfetcher"
 	"sneak.berlin/go/pixa/internal/imageprocessor"
 	"sneak.berlin/go/pixa/internal/imageproxy"
 	"sneak.berlin/go/pixa/internal/imagerequest"
 	"sneak.berlin/go/pixa/internal/imgcache"
 	"sneak.berlin/go/pixa/internal/seal"
 	"sneak.berlin/go/pixa/internal/signature"
 )
 // mismatchedSourcePath is the path of the source that
 // TestFirstBytesNotMatchingContentType serves on allowlistedHost. The mock
 // fetcher names a file's Content-Type from its extension, so the source is
 // sent as image/png.
 const mismatchedSourcePath = "/images/source.png"
 // newRoutesFetchingThrough returns both image routes, and the Handlers behind
 // them, whose image service fetches through fetcher, and which have
 // allowlistedHost on their allowlist. The handlers and the image service log
 // to log.
 func newRoutesFetchingThrough(
 	t *testing.T, fetcher httpfetcher.Fetcher, log *slog.Logger,
 ) (*Handlers, http.Handler) {
 	t.Helper()
 	cache, err := imgcache.NewCache(setupTestDB(t), imgcache.Config{
 		StateDir:    t.TempDir(),
 		NegativeTTL: 5 * time.Minute,
 		MaxBytes:    1 << 30,
 	}, prometheus.NewRegistry())
 	if err != nil {
 		t.Fatalf("imgcache.NewCache() error = %v", err)
 	}
 	svc, err := imageproxy.New(&imageproxy.Config{
 		Cache:   cache,
 		Fetcher: fetcher,
 		Processor: imageprocessor.New(imageprocessor.Params{
 			MaxInputBytes:           50 << 20,
 			MaxConcurrentProcessing: 2,
 		}),
 		MaxResponseSize: 50 << 20,
 		Logger:          log,
 	}, prometheus.NewRegistry())
 	if err != nil {
 		t.Fatalf("imageproxy.New() error = %v", err)
 	}
 	keys, err := seal.DeriveKeys(testSigningKey)
 	if err != nil {
 		t.Fatalf("seal.DeriveKeys() error = %v", err)
 	}
 	encGen := encurl.NewGenerator(keys.EncryptedURLKey)
 	h := &Handlers{
 		log:       log,
 		imgSvc:    svc,
 		encGen:    encGen,
 		signer:    signature.New(testSigningKey),
 		allowlist: allowlist.New([]string{allowlistedHost}),
 	}
 	r := chi.NewRouter()
 	r.Get("/v1/image/*", h.HandleImage())
 	r.Get("/v1/e/{token}/*", h.HandleImageEnc())
 	return h, r
 }
 // mismatchedSourcePlainURL returns the /v1/image/ URL of mismatchedSourcePath
 // on allowlistedHost at 50x50 as a JPEG.
 func mismatchedSourcePlainURL(*testing.T, *Handlers) string {
 	return "/v1/image/" + allowlistedHost + mismatchedSourcePath + "/50x50.jpeg"
 }
 // mismatchedSourceEncURL returns an encrypted /v1/e/ URL, made with h's
 // generator, of mismatchedSourcePath on allowlistedHost at 50x50 as a JPEG.
 func mismatchedSourceEncURL(t *testing.T, h *Handlers) string {
 	t.Helper()
 	token, err := h.encGen.Generate(&imagerequest.Request{
 		Source: imagerequest.Source{
 			Host: allowlistedHost,
 			Path: mismatchedSourcePath,
 		},
 		Transform: imagerequest.Transform{
 			Size:   imagerequest.Size{Width: 50, Height: 50},
 			Format: imagerequest.FormatJPEG,
 		},
 	}, time.Time{})
 	if err != nil {
 		t.Fatalf("Generate() error = %v", err)
 	}
 	return "/v1/e/" + token + "/img.jpg"
 }
 // loggedLevels reads the JSON log lines in logs and returns the messages
 // logged at each level.
 func loggedLevels(t *testing.T, logs *bytes.Buffer) map[string][]string {
 	t.Helper()
 	t.Logf("logged:\n%s", logs.String())
 	messages := make(map[string][]string)
 	dec := json.NewDecoder(logs)
 	for dec.More() {
 		var line struct {
 			Level string `json:"level"`
 			Msg   string `json:"msg"`
 		}
 		err := dec.Decode(&line)
 		if err != nil {
 			t.Fatalf("decoding log line: %v", err)
 		}
 		messages[line.Level] = append(messages[line.Level], line.Msg)
 	}
 	return messages
 }
 // TestFirstBytesNotMatchingContentType checks that both image routes answer
 // 415 for an upstream body whose first bytes are not those of the format its
 // Content-Type names, and log it as a refused source, not as an error of
 // pixa's. The next request for that source must answer 502 without fetching
 // it again, as after an upstream error status.
 func TestFirstBytesNotMatchingContentType(t *testing.T) {
 	t.Parallel()
 	bodies := map[string][]byte{
 		"JPEG sent as image/png":          generateTestJPEG(t, 10, 10, color.Black),
 		"text sent as image/png":          []byte("This is just text, not a PNG"),
 		"body too short to name a format": []byte("short"),
 	}
 	// The source's URL on each image route.
 	sourceURLs := map[string]func(*testing.T, *Handlers) string{
 		"plain URL":     mismatchedSourcePlainURL,
 		"encrypted URL": mismatchedSourceEncURL,
 	}
 	for bodyName, body := range bodies {
 		for urlName, sourceURL := range sourceURLs {
 			t.Run(urlName+", "+bodyName, func(t *testing.T) {
 				t.Parallel()
 				fetcher := &countingFetcher{
 					Fetcher: httpfetcher.NewMock(fstest.MapFS{
 						allowlistedHost + mismatchedSourcePath: &fstest.MapFile{
 							Data: body,
 						},
 					}),
 				}
 				var logs bytes.Buffer
 				h, routes := newRoutesFetchingThrough(t, fetcher,
 					slog.New(slog.NewJSONHandler(&logs, nil)))
 				target := sourceURL(t, h)
 				checkErrorBody(t, sendGet(t, routes, target),
 					http.StatusUnsupportedMediaType, "unsupported source format")
 				levels := loggedLevels(t, &logs)
 				if len(levels[slog.LevelError.String()]) != 0 {
 					t.Errorf("logged at error level: %q",
 						levels[slog.LevelError.String()])
 				}
 				if !slices.Contains(levels[slog.LevelWarn.String()], "source refused") {
 					t.Error(`no "source refused" line logged at warning level`)
 				}
 				checkErrorBody(t, sendGet(t, routes, target),
 					http.StatusBadGateway, "upstream error")
 				if n := fetcher.fetches.Load(); n != 1 {
 					t.Errorf("upstream fetched %d times, want 1", n)
 				}
 			})
 		}
 	}
 }
@@ -8,7 +8,7 @@ import (
 	"strconv"
 	"strings"
-	"sneak.berlin/go/pixa/internal/imagerequest"
+	"sneak.berlin/go/pixa/internal/imgcache"
 )
 // Errors for an Accept header that an auto URL cannot be served for.
@@ -18,17 +18,16 @@ var (
 		"image/jxl, image/avif, image/webp or image/jpeg")
 )
-// chooseAutoFormat returns the format to serve for the requested format: for
+// chooseAutoFormat replaces the format auto in req with the format
-// the format auto, the format formatForAccept chooses from r's Accept header,
+// formatForAccept chooses from r's Accept header, and adds Vary: Accept to the
 // and any other format as it is. For auto it adds Vary: Accept to the
 // response, which then depends on that header. It answers 400 for an Accept
 // header that is not valid and 406 for one that allows none of the formats,
-// and reports whether the image can be served.
+// and reports whether req can be served. Any other format is left as it is.
 func (s *Handlers) chooseAutoFormat(
-	w http.ResponseWriter, r *http.Request, requested imagerequest.Format,
+	w http.ResponseWriter, r *http.Request, req *imgcache.ImageRequest,
-) (imagerequest.Format, bool) {
+) bool {
-	if requested != imagerequest.FormatAuto {
+	if req.Format != imgcache.FormatAuto {
-		return requested, true
+		return true
 	}
 	w.Header().Add("Vary", "Accept")
@@ -37,16 +36,18 @@ func (s *Handlers) chooseAutoFormat(
 	if errors.Is(err, errNotAcceptable) {
 		s.respondError(w, err.Error(), http.StatusNotAcceptable)
-		return "", false
+		return false
 	}
 	if err != nil {
 		s.respondError(w, err.Error(), http.StatusBadRequest)
-		return "", false
+		return false
 	}
-	return format, true
+	req.Format = format
 	return true
 }
 // formatForAccept returns the format an auto URL is served in for the Accept
@@ -55,30 +56,30 @@ func (s *Handlers) chooseAutoFormat(
 // specific entry of image/jpeg, image/* and */* allows it, or when it names
 // nothing. A q of 0 refuses a format. JPEG XL, AVIF and WebP must be named, as
 // clients that cannot show them send image/* and */* too.
-func formatForAccept(accept string) (imagerequest.Format, error) {
+func formatForAccept(accept string) (imgcache.ImageFormat, error) {
 	qualities, err := parseAccept(accept)
 	if err != nil {
 		return "", err
 	}
 	if len(qualities) == 0 {
-		return imagerequest.FormatJPEG, nil
+		return imgcache.FormatJPEG, nil
 	}
-	if qualities[imagerequest.FormatJXL.MIMEType()] > 0 {
+	if qualities["image/jxl"] > 0 {
-		return imagerequest.FormatJXL, nil
+		return imgcache.FormatJXL, nil
 	}
-	if qualities[imagerequest.FormatAVIF.MIMEType()] > 0 {
+	if qualities["image/avif"] > 0 {
-		return imagerequest.FormatAVIF, nil
+		return imgcache.FormatAVIF, nil
 	}
-	if qualities[imagerequest.FormatWebP.MIMEType()] > 0 {
+	if qualities["image/webp"] > 0 {
-		return imagerequest.FormatWebP, nil
+		return imgcache.FormatWebP, nil
 	}
 	// For JPEG, the most specific entry the header has decides
-	quality, named := qualities[imagerequest.FormatJPEG.MIMEType()]
+	quality, named := qualities["image/jpeg"]
 	if !named {
 		quality, named = qualities["image/*"]
 	}
@@ -88,7 +89,7 @@ func formatForAccept(accept string) (imagerequest.Format, error) {
 	}
 	if quality > 0 {
-		return imagerequest.FormatJPEG, nil
+		return imgcache.FormatJPEG, nil
 	}
 	return "", errNotAcceptable
@@ -12,7 +12,8 @@ import (
 	"github.com/go-chi/chi/v5"
-	"sneak.berlin/go/pixa/internal/imagerequest"
+	"sneak.berlin/go/pixa/internal/encurl"
 	"sneak.berlin/go/pixa/internal/imgcache"
 )
 // The content types the tests below expect.
@@ -32,24 +33,24 @@ func TestFormatForAccept(t *testing.T) {
 	tests := []struct {
 		name    string
 		accept  string
-		want    imagerequest.Format
+		want    imgcache.ImageFormat
 		wantErr error
 	}{
 		{"AVIF-capable browser",
 			"image/avif,image/webp,image/apng,image/svg+xml,image/*,*/*;q=0.8",
-			imagerequest.FormatAVIF, nil},
+			imgcache.FormatAVIF, nil},
 		{"WebP-capable browser",
 			"image/webp,image/png,image/svg+xml,image/*;q=0.8,*/*;q=0.5",
-			imagerequest.FormatWebP, nil},
+			imgcache.FormatWebP, nil},
-		{"WebP only", webpType, imagerequest.FormatWebP, nil},
+		{"WebP only", webpType, imgcache.FormatWebP, nil},
-		{"neither", "image/png,image/*;q=0.8,*/*;q=0.5", imagerequest.FormatJPEG, nil},
+		{"neither", "image/png,image/*;q=0.8,*/*;q=0.5", imgcache.FormatJPEG, nil},
-		{"wildcard only", "*/*", imagerequest.FormatJPEG, nil},
+		{"wildcard only", "*/*", imgcache.FormatJPEG, nil},
-		{"image wildcard only", "image/*", imagerequest.FormatJPEG, nil},
+		{"image wildcard only", "image/*", imgcache.FormatJPEG, nil},
-		{"absent", "", imagerequest.FormatJPEG, nil},
+		{"absent", "", imgcache.FormatJPEG, nil},
-		{"q=0 on AVIF", "image/avif;q=0,image/webp,*/*", imagerequest.FormatWebP, nil},
+		{"q=0 on AVIF", "image/avif;q=0,image/webp,*/*", imgcache.FormatWebP, nil},
 		{"AVIF named twice, once with q=0", "image/avif,image/avif;q=0.0,*/*",
-			imagerequest.FormatJPEG, nil},
+			imgcache.FormatJPEG, nil},
-		{"upper case and spaces", " Image/AVIF ; Q=0.5 ", imagerequest.FormatAVIF, nil},
+		{"upper case and spaces", " Image/AVIF ; Q=0.5 ", imgcache.FormatAVIF, nil},
 		{"q=0 on JPEG", "image/jpeg;q=0,image/*", "", errNotAcceptable},
 		{"q=0 on everything", "*/*;q=0", "", errNotAcceptable},
 		{"PNG only", "image/png", "", errNotAcceptable},
@@ -75,33 +76,28 @@ func TestFormatForAccept(t *testing.T) {
 // autoPhotoURLs returns a signed /v1/image/ URL and an encrypted /v1/e/ URL,
 // both valid for a minute, for the JPEG at photoPath on signedHost at 50x50 in
-// the format auto. The first is signed with testSigningKey, the key the
+// the format auto, made with h's image service and generator.
 // handlers that newSignedHostServer builds check signatures with. The second
 // is made with h's generator.
 func autoPhotoURLs(t *testing.T, h *Handlers) (string, string) {
 	t.Helper()
-	signedURL := generateSignedURL(testSigningKey, &imagerequest.Request{
+	signedURL, err := h.imgSvc.GenerateSignedURL("", &imgcache.ImageRequest{
-		Source: imagerequest.Source{
+		SourceHost: signedHost,
-			Host: signedHost,
+		SourcePath: photoPath,
-			Path: photoPath,
+		Size:       imgcache.Size{Width: 50, Height: 50},
-		},
+		Format:     imgcache.FormatAuto,
 		Transform: imagerequest.Transform{
 			Size:   imagerequest.Size{Width: 50, Height: 50},
 			Format: imagerequest.FormatAuto,
 		},
 	}, time.Minute)
 	if err != nil {
 		t.Fatalf("GenerateSignedURL() error = %v", err)
 	}
-	token, err := h.encGen.Generate(&imagerequest.Request{
+	token, err := h.encGen.Generate(&encurl.Payload{
-		Source: imagerequest.Source{
+		SourceHost: signedHost,
-			Host: signedHost,
+		SourcePath: photoPath,
-			Path: photoPath,
+		Width:      50,
-		},
+		Height:     50,
-		Transform: imagerequest.Transform{
+		Format:     imgcache.FormatAuto,
-			Size:   imagerequest.Size{Width: 50, Height: 50},
+		ExpiresAt:  time.Now().Add(time.Minute).Unix(),
-			Format: imagerequest.FormatAuto,
+	})
 		},
 	}, time.Now().Add(time.Minute))
 	if err != nil {
 		t.Fatalf("Generate() error = %v", err)
 	}
@@ -186,18 +182,17 @@ func TestFormatAuto_ChosenFromAccept(t *testing.T) {
 func TestFormatAuto_SignatureCoversAuto(t *testing.T) {
 	t.Parallel()
-	_, srv := newSignedHostServer(t, slog.New(slog.DiscardHandler))
+	h, srv := newSignedHostServer(t, slog.New(slog.DiscardHandler))
-	signedForAVIF := generateSignedURL(testSigningKey, &imagerequest.Request{
+	signedForAVIF, err := h.imgSvc.GenerateSignedURL("", &imgcache.ImageRequest{
-		Source: imagerequest.Source{
+		SourceHost: signedHost,
-			Host: signedHost,
+		SourcePath: photoPath,
-			Path: photoPath,
+		Size:       imgcache.Size{Width: 50, Height: 50},
-		},
+		Format:     imgcache.FormatAVIF,
 		Transform: imagerequest.Transform{
 			Size:   imagerequest.Size{Width: 50, Height: 50},
 			Format: imagerequest.FormatAVIF,
 		},
 	}, time.Minute)
 	if err != nil {
 		t.Fatalf("GenerateSignedURL() error = %v", err)
 	}
 	target := strings.Replace(signedForAVIF, "/50x50.avif?", "/50x50.auto?", 1)
 	if target == signedForAVIF {
@@ -4,6 +4,7 @@ package handlers
 import (
 	"context"
 	"encoding/json"
 	"errors"
 	"log/slog"
 	"net/http"
 	"time"
@@ -11,13 +12,13 @@ import (
 	"go.uber.org/fx"
 	"sneak.berlin/go/pixa/internal/allowlist"
 	"sneak.berlin/go/pixa/internal/config"
 	"sneak.berlin/go/pixa/internal/database"
 	"sneak.berlin/go/pixa/internal/encurl"
 	"sneak.berlin/go/pixa/internal/healthcheck"
-	"sneak.berlin/go/pixa/internal/imageproxy"
+	"sneak.berlin/go/pixa/internal/httpfetcher"
 	"sneak.berlin/go/pixa/internal/imgcache"
 	"sneak.berlin/go/pixa/internal/logger"
 	"sneak.berlin/go/pixa/internal/seal"
 	"sneak.berlin/go/pixa/internal/session"
 	"sneak.berlin/go/pixa/internal/signature"
 )
 // Params defines dependencies for Handlers.
@@ -26,50 +27,70 @@ type Params struct {
 	Logger      *logger.Logger
 	Healthcheck *healthcheck.Healthcheck
 	Database    *database.Database
 	Config      *config.Config
 	Keys        seal.Keys
-	ImageService          *imageproxy.Proxy
+	// Fetcher, when provided, fetches upstream images in place of the
-	SessionManager        *session.Manager
+	// fetcher the handlers build from the config. Only tests provide one;
-	EncryptedURLGenerator *encurl.Generator
+	// pixad does not.
 	Fetcher httpfetcher.Fetcher `optional:"true"`
 }
 // Handlers provides HTTP request handlers.
 type Handlers struct {
 	log         *slog.Logger
 	hc          *healthcheck.Healthcheck
 	db          *database.Database
 	config      *config.Config
-	imgSvc      *imageproxy.Proxy
+	fetcher     httpfetcher.Fetcher
 	imgSvc      *imgcache.Service
 	imgCache    *imgcache.Cache
 	sessMgr     *session.Manager
 	encGen      *encurl.Generator
 	csrfProtect func(http.Handler) http.Handler
 	// signer checks the signature of a /v1/image/ URL with signing_key.
 	signer *signature.Signer
 	// allowlist matches the hosts of allowlist_hosts, which a /v1/image/
 	// URL may name without a signature.
 	allowlist *allowlist.HostAllowList
 	// refererBlocklist matches the hosts of referer_blocklist; its IsAllowed
 	// reports whether a URL's host is on that list.
 	refererBlocklist *allowlist.HostAllowList
 }
 // New creates a new Handlers instance.
-func New(_ fx.Lifecycle, params Params) *Handlers {
+func New(lc fx.Lifecycle, params Params) (*Handlers, error) {
-	log := params.Logger.Get()
+	csrfProtect, err := newCSRFProtect(params.Config.SigningKey, params.Config.Debug)
 	if err != nil {
 		return nil, err
 	}
-	return &Handlers{
+	s := &Handlers{
-		log:              log,
+		log:              params.Logger.Get(),
 		hc:               params.Healthcheck,
 		db:               params.Database,
 		config:           params.Config,
-		imgSvc:           params.ImageService,
+		fetcher:          params.Fetcher,
-		sessMgr:          params.SessionManager,
+		csrfProtect:      csrfProtect,
 		encGen:           params.EncryptedURLGenerator,
 		csrfProtect:      newCSRFProtect(params.Keys.CSRFKey, params.Config.Debug, log),
 		signer:           signature.New(params.Config.SigningKey),
 		allowlist:        allowlist.New(params.Config.AllowlistHosts),
 		refererBlocklist: allowlist.New(params.Config.RefererBlocklist),
 	}
 	lc.Append(fx.Hook{
 		//nolint:contextcheck // the cache's goroutines outlive OnStart; OnStop stops them
 		OnStart: func(_ context.Context) error {
 			return s.initImageService()
 		},
 		// The pending counts are written here, before the database's stop
 		// hook closes it.
 		OnStop: func(ctx context.Context) error {
 			if s.imgCache == nil {
 				return nil
 			}
 			return errors.Join(
 				s.imgCache.StopEviction(ctx),
 				s.imgCache.StopPendingCountWrites(ctx),
 			)
 		},
 	})
 	return s, nil
 }
 // WaitForProcessing waits until no image is being processed, or until ctx
@@ -78,6 +99,91 @@ func (s *Handlers) WaitForProcessing(ctx context.Context) int {
 	return s.imgSvc.WaitForProcessing(ctx)
 }
 // newCacheConfig builds the image cache's configuration from cfg.
 // cache_max_bytes: 0 disables the disk cache entirely; any other value
 // is the eviction limit in bytes; when it is omitted, the cache works
 // out the default limit itself.
 func newCacheConfig(cfg *config.Config, log *slog.Logger) imgcache.CacheConfig {
 	return imgcache.CacheConfig{
 		StateDir:           cfg.StateDir,
 		NegativeTTL:        imgcache.DefaultNegativeTTL,
 		MaxBytes:           cfg.CacheMaxBytes,
 		UseDefaultMaxBytes: !cfg.CacheMaxBytesExplicit,
 		DisableDiskCache:   cfg.CacheMaxBytesExplicit && cfg.CacheMaxBytes == 0,
 		Logger:             log,
 	}
 }
 // initImageService initializes the image cache and service.
 func (s *Handlers) initImageService() error {
 	cache, err := imgcache.NewCache(s.db.DB(), newCacheConfig(s.config, s.log))
 	if err != nil {
 		return err
 	}
 	s.imgCache = cache
 	// Background eviction: startup reconciliation, then periodic and
 	// write-pressure passes, and the removal of expired negative cache
 	// rows, which is all it does when the disk cache is disabled.
 	cache.StartEviction(imgcache.DefaultEvictionInterval)
 	// Writes the counts requests could not write by their deadline
 	cache.StartPendingCountWrites()
 	// Create the fetcher config
 	fetcherCfg := httpfetcher.DefaultConfig()
 	fetcherCfg.AllowHTTP = s.config.AllowHTTP
 	fetcherCfg.Timeout = s.config.UpstreamFetchTimeout
 	fetcherCfg.MaxResponseSize = s.config.UpstreamMaxResponseSize
 	if s.config.UpstreamConnectionsPerHost > 0 {
 		fetcherCfg.MaxConnectionsPerHost = s.config.UpstreamConnectionsPerHost
 	}
 	fetcherCfg.MaxConnections = s.config.UpstreamConnections
 	fetcherCfg.BlockedNetworks = s.config.BlockedNetworks
 	// Create the service. With no fetcher provided, it builds its own from
 	// fetcherCfg.
 	svc, err := imgcache.NewService(&imgcache.ServiceConfig{
 		Cache:                   cache,
 		FetcherConfig:           fetcherCfg,
 		Fetcher:                 s.fetcher,
 		SigningKey:              s.config.SigningKey,
 		Allowlist:               s.config.AllowlistHosts,
 		MaxConcurrentProcessing: s.config.MaxConcurrentProcessing,
 		Logger:                  s.log,
 	})
 	if err != nil {
 		return err
 	}
 	s.imgSvc = svc
 	s.log.Info("image service initialized")
 	// Initialize session manager (signing key is validated at config load
 	// time). Session cookies are always Secure/HttpOnly/SameSite=Strict.
 	sessMgr, err := session.NewManager(s.config.SigningKey)
 	if err != nil {
 		return err
 	}
 	s.sessMgr = sessMgr
 	// Initialize encrypted URL generator
 	encGen, err := encurl.NewGenerator(s.config.SigningKey)
 	if err != nil {
 		return err
 	}
 	s.encGen = encGen
 	s.log.Info("session manager and URL generator initialized")
 	return nil
 }
 func (s *Handlers) respondJSON(w http.ResponseWriter, data any, status int) {
 	w.Header().Set("Content-Type", "application/json")
 	w.WriteHeader(status)
@@ -18,20 +18,15 @@ import (
 	"time"
 	"github.com/go-chi/chi/v5"
 	"github.com/prometheus/client_golang/prometheus"
 	"sneak.berlin/go/pixa/internal/allowlist"
 	"sneak.berlin/go/pixa/internal/database"
 	"sneak.berlin/go/pixa/internal/httpfetcher"
 	"sneak.berlin/go/pixa/internal/imageprocessor"
 	"sneak.berlin/go/pixa/internal/imageproxy"
 	"sneak.berlin/go/pixa/internal/imagerequest"
 	"sneak.berlin/go/pixa/internal/imgcache"
 	"sneak.berlin/go/pixa/internal/signature"
 )
 // testFixtures contains test data.
 type testFixtures struct {
 	handler  *Handlers
 	service  *imgcache.Service
 	goodHost string
 }
@@ -50,37 +45,32 @@ func setupTestHandler(t *testing.T) *testFixtures {
 	tmpDir := t.TempDir()
 	db := setupTestDB(t)
-	cache, err := imgcache.NewCache(db, imgcache.Config{
+	cache, err := imgcache.NewCache(db, imgcache.CacheConfig{
 		StateDir:    tmpDir,
 		NegativeTTL: 5 * time.Minute,
-		MaxBytes:    1 << 30,
+	})
 	}, prometheus.NewRegistry())
 	if err != nil {
 		t.Fatalf("failed to create cache: %v", err)
 	}
-	svc, err := imageproxy.New(&imageproxy.Config{
+	svc, err := imgcache.NewService(&imgcache.ServiceConfig{
 		Cache:      cache,
 		Fetcher:    newMockFetcher(mockFS),
-		Processor: imageprocessor.New(imageprocessor.Params{
+		SigningKey: "test-signing-key-must-be-32-chars",
-			MaxInputBytes:           50 << 20,
+		Allowlist:  []string{goodHost},
-			MaxConcurrentProcessing: 2,
+	})
 		}),
 		MaxResponseSize: 50 << 20,
 	}, prometheus.NewRegistry())
 	if err != nil {
-		t.Fatalf("failed to create proxy: %v", err)
+		t.Fatalf("failed to create service: %v", err)
 	}
 	h := &Handlers{
 		imgSvc: svc,
 		log:    slog.Default(),
 		signer:    signature.New("test-signing-key-must-be-32-chars"),
 		allowlist: allowlist.New([]string{goodHost}),
 	}
 	return &testFixtures{
 		handler:  h,
 		service:  svc,
 		goodHost: goodHost,
 	}
 }
@@ -131,9 +121,10 @@ func newMockFetcher(fs fs.FS) *mockFetcher {
 }
 func (f *mockFetcher) Fetch(
-	_ context.Context, source imagerequest.Source, _, _ string,
+	_ context.Context, url string,
 ) (*httpfetcher.FetchResult, error) {
-	path := source.Host + source.Path
+	// Remove https:// prefix
 	path := url[8:] // Remove "https://"
 	data, err := fs.ReadFile(f.fs, path)
 	if err != nil {
@@ -257,90 +248,6 @@ func TestHandleImage_ConditionalRequest_IfNoneMatch_DifferentETag(t *testing.T)
 	}
 }
 // TestHandleImage_ConditionalRequest_EarlierETagGetsChangedImage serves an
 // image, changes it upstream, and requests it again with the ETag first
 // served, once the cache TTL has passed. The changed image must be served,
 // not 304 Not Modified.
 func TestHandleImage_ConditionalRequest_EarlierETagGetsChangedImage(t *testing.T) {
 	t.Parallel()
 	const host = "goodhost.example.com"
 	upstream := fstest.MapFS{
 		host + photoPath: &fstest.MapFile{
 			Data: generateTestJPEG(t, 100, 100, color.RGBA{255, 0, 0, 255}),
 		},
 	}
 	// A cache TTL of one nanosecond has passed by the second request
 	cache, err := imgcache.NewCache(setupTestDB(t), imgcache.Config{
 		StateDir:    t.TempDir(),
 		NegativeTTL: 5 * time.Minute,
 		CacheTTL:    time.Nanosecond,
 		MaxBytes:    1 << 30,
 	}, prometheus.NewRegistry())
 	if err != nil {
 		t.Fatalf("imgcache.NewCache() error = %v", err)
 	}
 	svc, err := imageproxy.New(&imageproxy.Config{
 		Cache:   cache,
 		Fetcher: newMockFetcher(upstream),
 		Processor: imageprocessor.New(imageprocessor.Params{
 			MaxInputBytes:           50 << 20,
 			MaxConcurrentProcessing: 2,
 		}),
 		MaxResponseSize: 50 << 20,
 		Logger:          slog.New(slog.DiscardHandler),
 	}, prometheus.NewRegistry())
 	if err != nil {
 		t.Fatalf("imageproxy.New() error = %v", err)
 	}
 	h := &Handlers{
 		imgSvc:    svc,
 		log:       slog.New(slog.DiscardHandler),
 		signer:    signature.New(testSigningKey),
 		allowlist: allowlist.New([]string{host}),
 	}
 	r := chi.NewRouter()
 	r.Get("/v1/image/*", h.HandleImage())
 	target := "/v1/image/" + host + photoPath + "/50x50.jpeg"
 	first := httptest.NewRecorder()
 	r.ServeHTTP(first,
 		httptest.NewRequestWithContext(t.Context(), http.MethodGet, target, nil))
 	etag := first.Header().Get("ETag")
 	if first.Code != http.StatusOK || etag == "" {
 		t.Fatalf("first request: status = %d, ETag = %q, want %d and an ETag",
 			first.Code, etag, http.StatusOK)
 	}
 	upstream[host+photoPath] = &fstest.MapFile{
 		Data: generateTestJPEG(t, 100, 100, color.RGBA{0, 0, 255, 255}),
 	}
 	req := httptest.NewRequestWithContext(t.Context(), http.MethodGet, target, nil)
 	req.Header.Set("If-None-Match", etag)
 	second := httptest.NewRecorder()
 	r.ServeHTTP(second, req)
 	t.Logf("first ETag %s; with it after the change: status %d, ETag %s, %d bytes",
 		etag, second.Code, second.Header().Get("ETag"), second.Body.Len())
 	if second.Code != http.StatusOK {
 		t.Fatalf("status = %d, want %d with the changed image",
 			second.Code, http.StatusOK)
 	}
 	if bytes.Equal(second.Body.Bytes(), first.Body.Bytes()) {
 		t.Error("the image served is the one made before the change")
 	}
 }
 func TestHandleImage_ETagHeader(t *testing.T) {
 	t.Parallel()
@@ -1,31 +1,22 @@
 package handlers
 import (
 	"context"
 	"errors"
 	"fmt"
 	"io"
 	"net/http"
 	"net/url"
 	"strconv"
 	"strings"
 	"time"
 	"github.com/go-chi/chi/v5"
 	"github.com/go-chi/chi/v5/middleware"
 	"sneak.berlin/go/pixa/internal/encurl"
 	"sneak.berlin/go/pixa/internal/httpfetcher"
 	"sneak.berlin/go/pixa/internal/imageprocessor"
-	"sneak.berlin/go/pixa/internal/imageproxy"
+	"sneak.berlin/go/pixa/internal/imgcache"
 	"sneak.berlin/go/pixa/internal/imagerequest"
 	"sneak.berlin/go/pixa/internal/magic"
 )
 // statusClientClosedRequest is the status nginx calls "client closed
 // request". The image routes answer it when the client goes away before its
 // image is ready, unless its request is the one making the image. Nobody reads
 // it; it is for logs and metrics.
 const statusClientClosedRequest = 499
 // HandleImage handles the main image proxy route:
 // /v1/image/<host>/<path>/<width>x<height>.<format>, or with no format
 // /v1/image/<host>/<path>/<width>x<height>
@@ -35,17 +26,17 @@ func (s *Handlers) HandleImage() http.HandlerFunc {
 			return
 		}
-		req, sig, expires, ok := s.parseImageRequest(w, r)
+		req, ok := s.parseImageRequest(w, r)
 		if !ok {
 			return
 		}
 		// Validate signature if required
-		err := s.validateSignature(req, sig, expires)
+		err := s.imgSvc.ValidateRequest(req)
 		if err != nil {
 			s.log.Warn("signature validation failed",
-				"host", req.Source.Host,
+				"host", req.SourceHost,
-				"path", req.Source.Path,
+				"path", req.SourcePath,
 				"error", err,
 			)
 			s.respondError(w, "unauthorized", http.StatusUnauthorized)
@@ -53,7 +44,27 @@ func (s *Handlers) HandleImage() http.HandlerFunc {
 			return
 		}
-		s.serveImage(w, r, req, expires)
+		// The signature covers the format auto, not the format chosen
 		if !s.chooseAutoFormat(w, r, req) {
 			return
 		}
 		// Get cache key for logging
 		cacheKey := imgcache.CacheKey(req)
 		// Get the image (from cache or fetch/process)
 		startTime := time.Now()
 		resp, err := s.imgSvc.Get(r.Context(), req)
 		if err != nil {
 			s.respondImageError(w, req, err)
 			return
 		}
 		defer func() { _ = resp.Content.Close() }()
 		s.writeImageResponse(w, r, req, resp, cacheKey, startTime)
 	}
 }
@@ -69,28 +80,30 @@ func (s *Handlers) HandleRobotsTxt() http.HandlerFunc {
 	}
 }
-// parseImageRequest parses the image URL's path and query parameters into
+// parseImageRequest parses the wildcard path and query parameters into
-// an image request, and returns it with the URL's signature and expiry. On
+// an ImageRequest. On invalid input it writes an error response and
-// invalid input it writes an error response and returns false.
+// returns false.
 func (s *Handlers) parseImageRequest(
 	w http.ResponseWriter, r *http.Request,
-) (*imagerequest.Request, string, time.Time, bool) {
+) (*imgcache.ImageRequest, bool) {
-	// The path is parsed decoded once, as r.URL.Path holds it, and not from
+	// Get the wildcard path from chi
-	// chi's wildcard: chi routes on the path as the client wrote it whenever
+	pathParam := chi.URLParam(r, "*")
-	// that is not Go's own encoding of it, so its wildcard would still hold
+
-	// the %3F before a source query when, say, a "/" in the query is written
+	// Parse the URL path
-	// as %2F
+	parsed, err := imgcache.ParseImagePath(pathParam)
 	req, err := imagerequest.ParseImageURL(r.URL.Path)
 	if err != nil {
 		s.log.Warn("failed to parse image URL",
-			"path", r.URL.Path,
+			"path", pathParam,
 			"error", err,
 		)
 		s.respondError(w, "invalid image URL: "+err.Error(), http.StatusBadRequest)
-		return nil, "", time.Time{}, false
+		return nil, false
 	}
 	// Convert to ImageRequest
 	req := parsed.ToImageRequest()
 	// Parse signature params from query string. r.URL.Query() would silently
 	// drop a pair it cannot decode, such as q=80%, so that q would be served
 	// at 85; a query string that cannot be decoded is refused instead. A
@@ -101,7 +114,7 @@ func (s *Handlers) parseImageRequest(
 		s.respondError(w, fmt.Sprintf("invalid query string %q: %v",
 			r.URL.RawQuery, err), http.StatusBadRequest)
-		return nil, "", time.Time{}, false
+		return nil, false
 	}
 	for name, values := range query {
@@ -109,15 +122,17 @@ func (s *Handlers) parseImageRequest(
 			s.respondError(w, fmt.Sprintf("invalid %s: given more than once",
 				name), http.StatusBadRequest)
-			return nil, "", time.Time{}, false
+			return nil, false
 		}
 	}
-	expires, err := parseExpires(query)
+	req.Signature = query.Get("sig")
 	req.Expires, err = parseExpires(query)
 	if err != nil {
 		s.respondError(w, err.Error(), http.StatusBadRequest)
-		return nil, "", time.Time{}, false
+		return nil, false
 	}
 	// Parse optional quality and fit params. Only a q missing from the URL is
@@ -129,76 +144,51 @@ func (s *Handlers) parseImageRequest(
 		s.respondError(w, `invalid q: not a number, got ""`,
 			http.StatusBadRequest)
-		return nil, "", time.Time{}, false
+		return nil, false
 	}
-	req.Transform.Quality, err = parseFormInt(query, "q",
+	req.Quality, err = parseFormInt(query, "q",
 		encurl.DefaultQuality, minQuality, maxQuality)
 	if err != nil {
 		s.respondError(w, fmt.Sprintf("%v, got %q", err, qStr),
 			http.StatusBadRequest)
-		return nil, "", time.Time{}, false
+		return nil, false
 	}
 	// Only a fit missing from the URL is cover. A fit in the URL that is not a
 	// fit mode is refused by the fit-mode check below; that check would take an
 	// empty fit as missing, so an empty one is refused here.
-	req.Transform.FitMode = imagerequest.Fit(query.Get("fit"))
+	req.FitMode = imgcache.FitMode(query.Get("fit"))
-	if query.Has("fit") && req.Transform.FitMode == "" {
+	if query.Has("fit") && req.FitMode == "" {
 		s.respondError(w, `invalid fit: not a fit mode, got ""`, http.StatusBadRequest)
-		return nil, "", time.Time{}, false
+		return nil, false
 	}
 	// Default fit mode if not set
-	if req.Transform.FitMode == "" {
+	if req.FitMode == "" {
-		req.Transform.FitMode = imagerequest.FitCover
+		req.FitMode = imgcache.FitCover
 	}
 	// Enforce dimension and fit-mode bounds, shared with the encrypted-URL
 	// route. Dimensions are already bounded by the path parser above; this
 	// also rejects an unrecognized fit mode with 400 instead of letting it
 	// reach the processor as a 500.
-	err = imagerequest.ValidateImageRequest(req)
+	err = imgcache.ValidateImageRequest(req)
 	if err != nil {
 		s.respondError(w, "invalid image request: "+err.Error(),
 			http.StatusBadRequest)
-		return nil, "", time.Time{}, false
+		return nil, false
 	}
-	return req, query.Get("sig"), expires, true
+	return req, true
 }
 // validateSignature returns nil when the source host of req is on
 // allowlist_hosts and names no port. Otherwise it verifies sig, the URL's
 // signature of req, and expires, the URL's expiry.
 func (s *Handlers) validateSignature(
 	req *imagerequest.Request, sig string, expires time.Time,
 ) error {
 	// An allowlist entry names no port, so a host followed by ":", with or
 	// without a port, needs a signature. Go's URL type reads the port as the
 	// fetcher does: in an IPv6 address written without brackets, such as
 	// 2001:db8::1:8443, it is what follows the last ":". This is checked here
 	// and not in allowlist.IsAllowed, which also matches referer_blocklist,
 	// where a Referer must be blocked whatever its port. Port and IsAllowed
 	// read only the host of a URL.
 	sourceURL := &url.URL{Host: req.Source.Host}
 	hostHasPort := sourceURL.Port() != "" ||
 		strings.HasSuffix(sourceURL.Host, ":")
 	if !hostHasPort && s.allowlist.IsAllowed(sourceURL) {
 		return nil
 	}
 	// Signature required for non-allowed hosts
 	return s.signer.Verify(req, sig, expires)
 }
 // parseExpires reads the exp query parameter, a Unix time in seconds. An exp
-// missing from the URL gives the zero time, which the signature check refuses
+// missing from the URL gives the zero time, which the signature check takes
-// as a missing exp. An exp in the URL that is not a whole number, an empty
+// as no expiration. An exp in the URL that is not a whole number, an empty
 // one included, is an error naming exp and the value.
 func parseExpires(query url.Values) (time.Time, error) {
 	if !query.Has("exp") {
@@ -226,101 +216,55 @@ func (s *Handlers) HandleTooManyRequests() http.HandlerFunc {
 	}
 }
-// respondImageError answers err, the image service's error for req, on both
+// respondImageError maps image retrieval errors to HTTP responses.
 // image routes. It logs a 500 at error level, as pixa's own failure. It logs
 // the other answers at warn level, since the client, the upstream or a full
 // limit caused them. The 415 for a source refused for its first bytes is not
 // logged here, because the image service logs it.
 func (s *Handlers) respondImageError(
-	w http.ResponseWriter, req *imagerequest.Request, err error,
+	w http.ResponseWriter, req *imgcache.ImageRequest, err error,
 ) {
-	// The image service has logged this as a refused source
+	s.log.Error("failed to get image",
-	if isFirstBytesMismatch(err) {
+		"host", req.SourceHost,
 		"path", req.SourcePath,
 		"error", err,
 	)
 	// Check for specific error types
 	if errors.Is(err, httpfetcher.ErrSSRFBlocked) {
 		s.respondError(w, "forbidden", http.StatusForbidden)
 		return
 	}
 	if errors.Is(err, httpfetcher.ErrUpstreamError) {
 		s.respondError(w, "upstream error", http.StatusBadGateway)
 		return
 	}
 	if errors.Is(err, httpfetcher.ErrTooManyConnections) ||
 		errors.Is(err, imageprocessor.ErrTooManyImages) ||
 		errors.Is(err, imgcache.ErrProcessingTimedOut) {
 		s.respondError(w, "server busy, try again later",
 			http.StatusServiceUnavailable)
 		return
 	}
 	if errors.Is(err, httpfetcher.ErrInvalidContentType) ||
 		errors.Is(err, imageprocessor.ErrUnsupportedInputFormat) {
 		s.respondError(w, "unsupported source format",
 			http.StatusUnsupportedMediaType)
 		return
 	}
-	var (
+	if errors.Is(err, imageprocessor.ErrOutputTooLarge) {
-		status  int
+		s.respondError(w, fmt.Sprintf("size too large for the source: the side "+
 		message string
 	)
 	switch {
 	case errors.Is(err, httpfetcher.ErrSSRFBlocked):
 		status, message = http.StatusForbidden, "forbidden"
 	case errors.Is(err, httpfetcher.ErrUpstreamError),
 		errors.Is(err, httpfetcher.ErrInvalidHost),
 		errors.Is(err, httpfetcher.ErrUpstreamRequestFailed):
 		status, message = http.StatusBadGateway, "upstream error"
 	case errors.Is(err, httpfetcher.ErrUpstreamTimeout):
 		status, message = http.StatusGatewayTimeout, "upstream timeout"
 	case errors.Is(err, httpfetcher.ErrTooManyConnections),
 		errors.Is(err, imageprocessor.ErrTooManyImages),
 		errors.Is(err, imageproxy.ErrProcessingTimedOut):
 		status = http.StatusServiceUnavailable
 		message = "server busy, try again later"
 	case errors.Is(err, httpfetcher.ErrInvalidContentType),
 		errors.Is(err, imageprocessor.ErrUnsupportedInputFormat):
 		status = http.StatusUnsupportedMediaType
 		message = "unsupported source format"
 	case errors.Is(err, imageprocessor.ErrSVGTooThin):
 		status = http.StatusUnsupportedMediaType
 		message = fmt.Sprintf("SVG source too thin to render: one side is "+
 			"more than %d times the other", imageprocessor.MaxInputDimension)
 	case errors.Is(err, imageprocessor.ErrSVGRenderFailed):
 		status = http.StatusUnsupportedMediaType
 		message = fmt.Sprintf("SVG source could not be rendered: it is not "+
 			"valid, or it takes more than %d seconds or %d GiB of memory to "+
 			"render", int(imageprocessor.SVGRenderTimeout.Seconds()),
 			imageprocessor.MaxSVGRenderMemory/bytesPerGiB)
 	case errors.Is(err, imageprocessor.ErrOutputTooLarge):
 		status = http.StatusBadRequest
 		message = fmt.Sprintf("size too large for the source: the side "+
 			"computed from its proportions is above %d",
-			imageprocessor.MaxOutputDimension)
+			imageprocessor.MaxOutputDimension), http.StatusBadRequest)
 	case errors.Is(err, imageprocessor.ErrSVGNotOriginalSize):
 		status = http.StatusBadRequest
 		message = "an SVG source is returned as SVG only at the orig size; " +
 			"ask for another format to resize it"
 	case errors.Is(err, imageprocessor.ErrSVGTooLargeForOrigSize):
 		status = http.StatusBadRequest
 		message = fmt.Sprintf("SVG source above %d on a side: give a size "+
 			"to render it at", imageprocessor.MaxOutputDimension)
 	case errors.Is(err, imageprocessor.ErrAVIFOutputTooLarge):
 		status = http.StatusBadRequest
 		message = fmt.Sprintf("size too large for AVIF: the output "+
 			"would be above %d pixels", imageprocessor.MaxAVIFOutputPixels)
 	default:
 		s.log.Error("failed to get image",
 			"host", req.Source.Host,
 			"path", req.Source.Path,
 			"error", err,
 		)
 		s.respondError(w, "internal error", http.StatusInternalServerError)
 		return
 	}
-	s.log.Warn("failed to get image",
+	s.respondError(w, "internal error", http.StatusInternalServerError)
 		"host", req.Source.Host,
 		"path", req.Source.Path,
 		"error", err,
 	)
 	s.respondError(w, message, status)
 }
 // bytesPerGiB is the number of bytes in a GiB.
 const bytesPerGiB = 1 << 30
 // isFirstBytesMismatch reports whether err refuses an upstream body whose
 // first bytes are not those of the format its Content-Type names. That is the
 // upstream's error, not pixa's.
 func isFirstBytesMismatch(err error) bool {
 	return errors.Is(err, magic.ErrMagicByteMismatch) ||
 		errors.Is(err, magic.ErrUnknownFormat) ||
 		errors.Is(err, magic.ErrNotEnoughData)
 }
 // cacheControl returns the Cache-Control header for an image served through a
@@ -341,26 +285,6 @@ func cacheControl(expires time.Time) string {
 	return fmt.Sprintf("public, max-age=%d, immutable", int64(maxAge/time.Second))
 }
 // svgContentSecurityPolicyValue is the Content-Security-Policy header value
 // of an SVG response, in place of the middleware's. A browser that opens the
 // SVG applies its styles and draws its embedded data: images, but runs none
 // of its scripts and loads nothing else. The styles need unsafe-inline, as an
 // SVG keeps them inline, in style elements and attributes.
 const svgContentSecurityPolicyValue = "default-src 'none'; " +
 	"style-src 'unsafe-inline'; " +
 	"img-src data:; " +
 	"frame-ancestors 'none'; " +
 	"sandbox"
 // setSVGContentSecurityPolicy sets the Content-Security-Policy in header to
 // svgContentSecurityPolicyValue when contentType is that of SVG. Any other
 // response keeps the middleware's policy.
 func setSVGContentSecurityPolicy(header http.Header, contentType string) {
 	if contentType == imagerequest.FormatSVG.MIMEType() {
 		header.Set("Content-Security-Policy", svgContentSecurityPolicyValue)
 	}
 }
 // refuseBlockedReferer answers 403 with a JSON error when the request's Referer
 // names a host on referer_blocklist, and reports whether it answered. A request
 // with no Referer, or one that does not parse as a URL with a host, is not
@@ -397,60 +321,22 @@ func notModified(w http.ResponseWriter, r *http.Request, etag string) bool {
 	return true
 }
-// serveImage serves the image that req asks for. Both image routes call it
+// writeImageResponse writes headers and streams the image content,
-// once they have the request and its URL's expiry, which ends the
+// handling conditional and HEAD requests.
-// Cache-Control max-age. It chooses the format for the format auto, answers
+func (s *Handlers) writeImageResponse(
 // If-None-Match with 304 and HEAD with the headers only. It answers 499 when
 // the image service stopped because the client went away, and any other error
 // of the image service with respondImageError.
 func (s *Handlers) serveImage(
 	w http.ResponseWriter, r *http.Request,
-	req *imagerequest.Request, expires time.Time,
+	req *imgcache.ImageRequest, resp *imgcache.ImageResponse,
 	cacheKey imgcache.VariantKey, startTime time.Time,
 ) {
 	// The signature or the token covers the format auto, not the format chosen
 	format, ok := s.chooseAutoFormat(w, r, req.Transform.Format)
 	if !ok {
 		return
 	}
 	req.Transform.Format = format
 	startTime := time.Now()
 	resp, err := s.imgSvc.Get(r.Context(), req)
 	// The client went away before its image was ready, which is not pixa's
 	// failure. A cancellation while the request's context is live is pixa's,
 	// and respondImageError answers it 500.
 	if errors.Is(err, context.Canceled) && r.Context().Err() != nil {
 		s.log.Info("client went away before the image was ready",
 			"request_id", middleware.GetReqID(r.Context()),
 			"host", req.Source.Host,
 			"path", req.Source.Path,
 		)
 		w.WriteHeader(statusClientClosedRequest)
 		return
 	}
 	if err != nil {
 		s.respondImageError(w, req, err)
 		return
 	}
 	defer func() { _ = resp.Content.Close() }()
 	// Set response headers
 	w.Header().Set("Content-Type", resp.ContentType)
 	setSVGContentSecurityPolicy(w.Header(), resp.ContentType)
 	if resp.ContentLength > 0 {
 		w.Header().Set("Content-Length", strconv.FormatInt(resp.ContentLength, 10))
 	}
 	// Cache control headers
-	w.Header().Set("Cache-Control", cacheControl(expires))
+	w.Header().Set("Cache-Control", cacheControl(req.Expires))
 	w.Header().Set("X-Pixa-Cache", string(resp.CacheStatus))
 	if notModified(w, r, resp.ETag) {
@@ -467,31 +353,21 @@ func (s *Handlers) serveImage(
 	// Stream the response
 	w.WriteHeader(http.StatusOK)
 	// A failed write is most often a client that has gone away, not pixa's
 	// failure, so it is logged at warn level
 	servedBytes, err := io.Copy(w, resp.Content)
 	if err != nil {
-		s.log.Warn("failed to write response",
+		s.log.Error("failed to write response",
 			"request_id", middleware.GetReqID(r.Context()),
 			"host", req.Source.Host,
 			"path", req.Source.Path,
 			"served_bytes", servedBytes,
 			"error", err,
 		)
 		return
 	}
 	// Log cache status and timing after serving
 	duration := time.Since(startTime)
 	s.log.Info("image served",
 		"request_id", middleware.GetReqID(r.Context()),
-		"cache_key", imagerequest.CacheKey(req),
+		"cache_key", cacheKey,
 		"host", req.Source.Host,
 		"path", req.Source.Path,
 		"cache_status", resp.CacheStatus,
 		"duration_ms", duration.Milliseconds(),
-		"format", req.Transform.Format,
+		"format", req.Format,
 		"served_bytes", servedBytes,
 		"fetched_bytes", resp.FetchedBytes,
 	)
@@ -12,16 +12,9 @@ import (
 	"time"
 	"github.com/go-chi/chi/v5"
 	"github.com/prometheus/client_golang/prometheus"
 	"sneak.berlin/go/pixa/internal/allowlist"
 	"sneak.berlin/go/pixa/internal/encurl"
 	"sneak.berlin/go/pixa/internal/imageprocessor"
 	"sneak.berlin/go/pixa/internal/imageproxy"
 	"sneak.berlin/go/pixa/internal/imagerequest"
 	"sneak.berlin/go/pixa/internal/imgcache"
 	"sneak.berlin/go/pixa/internal/seal"
 	"sneak.berlin/go/pixa/internal/signature"
 )
 // photoPath is the path of the JPEG that newSignedHostServer serves.
@@ -36,46 +29,37 @@ func newSignedHostServer(
 ) (*Handlers, http.Handler) {
 	t.Helper()
-	cache, err := imgcache.NewCache(setupTestDB(t), imgcache.Config{
+	cache, err := imgcache.NewCache(setupTestDB(t), imgcache.CacheConfig{
 		StateDir:    t.TempDir(),
 		NegativeTTL: 5 * time.Minute,
-		MaxBytes:    1 << 30,
+	})
 	}, prometheus.NewRegistry())
 	if err != nil {
 		t.Fatalf("imgcache.NewCache() error = %v", err)
 	}
 	jpegData := generateTestJPEG(t, 100, 100, color.RGBA{255, 0, 0, 255})
-	svc, err := imageproxy.New(&imageproxy.Config{
+	svc, err := imgcache.NewService(&imgcache.ServiceConfig{
 		Cache: cache,
 		Fetcher: newMockFetcher(fstest.MapFS{
 			signedHost + photoPath: &fstest.MapFile{Data: jpegData},
 		}),
-		Processor: imageprocessor.New(imageprocessor.Params{
+		SigningKey: testSigningKey,
 			MaxInputBytes:           50 << 20,
 			MaxConcurrentProcessing: 2,
 		}),
 		MaxResponseSize: 50 << 20,
 		Logger:     log,
-	}, prometheus.NewRegistry())
+	})
 	if err != nil {
-		t.Fatalf("imageproxy.New() error = %v", err)
+		t.Fatalf("imgcache.NewService() error = %v", err)
 	}
-	keys, err := seal.DeriveKeys(testSigningKey)
+	encGen, err := encurl.NewGenerator(testSigningKey)
 	if err != nil {
-		t.Fatalf("seal.DeriveKeys() error = %v", err)
+		t.Fatalf("encurl.NewGenerator() error = %v", err)
 	}
 	encGen := encurl.NewGenerator(keys.EncryptedURLKey)
 	h := &Handlers{
 		log:    log,
 		imgSvc: svc,
 		encGen: encGen,
 		signer:    signature.New(testSigningKey),
 		allowlist: allowlist.New(nil),
 	}
 	r := chi.NewRouter()
@@ -121,18 +105,17 @@ func getMaxAge(t *testing.T, srv http.Handler, target string) int {
 func TestHandleImage_SignedURL_MaxAgeEndsAtExp(t *testing.T) {
 	t.Parallel()
-	_, srv := newSignedHostServer(t, slog.New(slog.DiscardHandler))
+	h, srv := newSignedHostServer(t, slog.New(slog.DiscardHandler))
-	signedURL := generateSignedURL(testSigningKey, &imagerequest.Request{
+	signedURL, err := h.imgSvc.GenerateSignedURL("", &imgcache.ImageRequest{
-		Source: imagerequest.Source{
+		SourceHost: signedHost,
-			Host: signedHost,
+		SourcePath: photoPath,
-			Path: photoPath,
+		Size:       imgcache.Size{Width: 50, Height: 50},
-		},
+		Format:     imgcache.FormatJPEG,
 		Transform: imagerequest.Transform{
 			Size:   imagerequest.Size{Width: 50, Height: 50},
 			Format: imagerequest.FormatJPEG,
 		},
 	}, time.Minute)
 	if err != nil {
 		t.Fatalf("GenerateSignedURL() error = %v", err)
 	}
 	maxAge := getMaxAge(t, srv, signedURL)
 	if maxAge < 50 || maxAge > 60 {
@@ -185,12 +168,12 @@ func TestHandleImageEnc_MaxAge(t *testing.T) {
 	tests := []struct {
 		name        string
-		ttl         time.Duration
+		expiresAt   int64
 		wantAtLeast int
 		wantAtMost  int
 	}{
-		{"60 second TTL", time.Minute, 50, 60},
+		{"60 second TTL", time.Now().Add(time.Minute).Unix(), 50, 60},
-		{"two-year TTL", 2 * 365 * 24 * time.Hour, 31536000, 31536000},
+		{"two-year TTL", time.Now().Add(2 * 365 * 24 * time.Hour).Unix(), 31536000, 31536000},
 		{"no TTL", 0, 31536000, 31536000},
 	}
@@ -200,24 +183,14 @@ func TestHandleImageEnc_MaxAge(t *testing.T) {
 			h, srv := newSignedHostServer(t, slog.New(slog.DiscardHandler))
-			// The expiry is set here, not in the table: a parallel subtest
+			token, err := h.encGen.Generate(&encurl.Payload{
-			// can wait behind other tests for more than the 10 seconds the
+				SourceHost: signedHost,
-			// 60 second case allows.
+				SourcePath: photoPath,
-			var expires time.Time
+				Width:      50,
-			if tt.ttl != 0 {
+				Height:     50,
-				expires = time.Now().Add(tt.ttl)
+				Format:     imgcache.FormatJPEG,
-			}
+				ExpiresAt:  tt.expiresAt,
-
+			})
 			token, err := h.encGen.Generate(&imagerequest.Request{
 				Source: imagerequest.Source{
 					Host: signedHost,
 					Path: photoPath,
 				},
 				Transform: imagerequest.Transform{
 					Size:   imagerequest.Size{Width: 50, Height: 50},
 					Format: imagerequest.FormatJPEG,
 				},
 			}, expires)
 			if err != nil {
 				t.Fatalf("Generate() error = %v", err)
 			}
@@ -1,30 +1,19 @@
 package handlers
 import (
 	"bytes"
 	"context"
 	"encoding/json"
 	"fmt"
 	"image/color"
 	"io"
 	"log/slog"
 	"net/http"
 	"net/http/httptest"
 	"slices"
 	"strings"
 	"syscall"
 	"testing"
 	"testing/fstest"
 	"time"
 	"github.com/go-chi/chi/v5"
 	"github.com/go-chi/chi/v5/middleware"
 	"github.com/prometheus/client_golang/prometheus"
 	"sneak.berlin/go/pixa/internal/allowlist"
 	"sneak.berlin/go/pixa/internal/httpfetcher"
 	"sneak.berlin/go/pixa/internal/imageprocessor"
 	"sneak.berlin/go/pixa/internal/imageproxy"
 	"sneak.berlin/go/pixa/internal/imagerequest"
 	"sneak.berlin/go/pixa/internal/imgcache"
 	"sneak.berlin/go/pixa/internal/signature"
 )
@@ -34,38 +23,29 @@ import (
 const allowlistedHost = "allowed.example.com"
 // newImageRoute returns the image route of a Handlers whose service fetches
-// with fetcher, and which checks signatures with testSigningKey.
+// with fetcher and checks signatures with testSigningKey.
 func newImageRoute(t *testing.T, fetcher httpfetcher.Fetcher) http.Handler {
 	t.Helper()
-	cache, err := imgcache.NewCache(setupTestDB(t), imgcache.Config{
+	cache, err := imgcache.NewCache(setupTestDB(t), imgcache.CacheConfig{
 		StateDir:    t.TempDir(),
 		NegativeTTL: 5 * time.Minute,
-		MaxBytes:    1 << 30,
+	})
 	}, prometheus.NewRegistry())
 	if err != nil {
 		t.Fatalf("failed to create cache: %v", err)
 	}
-	svc, err := imageproxy.New(&imageproxy.Config{
+	svc, err := imgcache.NewService(&imgcache.ServiceConfig{
 		Cache:      cache,
 		Fetcher:    fetcher,
-		Processor: imageprocessor.New(imageprocessor.Params{
+		SigningKey: testSigningKey,
-			MaxInputBytes:           50 << 20,
+		Allowlist:  []string{allowlistedHost},
-			MaxConcurrentProcessing: 2,
+	})
 		}),
 		MaxResponseSize: 50 << 20,
 	}, prometheus.NewRegistry())
 	if err != nil {
-		t.Fatalf("failed to create proxy: %v", err)
+		t.Fatalf("failed to create service: %v", err)
 	}
-	h := &Handlers{
+	h := &Handlers{imgSvc: svc, log: slog.New(slog.DiscardHandler)}
 		imgSvc:    svc,
 		log:       slog.New(slog.DiscardHandler),
 		signer:    signature.New(testSigningKey),
 		allowlist: allowlist.New([]string{allowlistedHost}),
 	}
 	r := chi.NewRouter()
 	r.Get("/v1/image/*", h.HandleImage())
@@ -74,7 +54,7 @@ func newImageRoute(t *testing.T, fetcher httpfetcher.Fetcher) http.Handler {
 }
 // newPhotoFetcher returns a mock fetcher that serves a JPEG at photoPath on
-// each of hosts, and answers any other source with an upstream error.
+// each of hosts, and answers any other URL with an upstream error.
 func newPhotoFetcher(t *testing.T, hosts ...string) *httpfetcher.MockFetcher {
 	t.Helper()
@@ -101,27 +81,19 @@ func photoURLWithSig(host, sig string, expires time.Time) string {
 	return fmt.Sprintf("%s?sig=%s&exp=%d", photoURL(host), sig, expires.Unix())
 }
 // photoRequest returns the image request of photoURL(host) at the default
 // quality and fit.
 func photoRequest(host string) *imagerequest.Request {
 	return &imagerequest.Request{
 		Source: imagerequest.Source{
 			Host: host,
 			Path: photoPath,
 		},
 		Transform: imagerequest.Transform{
 			Size:    imagerequest.Size{Width: 50, Height: 50},
 			Format:  imagerequest.FormatJPEG,
 			Quality: 85,
 			FitMode: imagerequest.FitCover,
 		},
 	}
 }
 // photoSignature returns the signature of photoURL(host) at the default
 // quality and fit, made with key and expiring at expires.
 func photoSignature(key, host string, expires time.Time) string {
-	return signature.New(key).Sign(photoRequest(host), expires)
+	return signature.New(key).Sign(&signature.Request{
 		SourceHost: host,
 		SourcePath: photoPath,
 		Width:      50,
 		Height:     50,
 		Format:     string(imgcache.FormatJPEG),
 		Quality:    85,
 		FitMode:    string(imgcache.FitCover),
 		Expires:    expires,
 	})
 }
 // sendGet sends a GET for target to route and returns the response.
@@ -192,12 +164,7 @@ func TestHandleImage_ErrorAnswers(t *testing.T) {
 	photos := newPhotoFetcher(t,
 		signedHost, parentHost, siblingHost, subdomainHost, appendedHost)
 	// The real fetcher refuses localhost before any lookup or connection.
-	realFetcher := httpfetcher.New(&httpfetcher.Config{
+	realFetcher := httpfetcher.New(httpfetcher.DefaultConfig())
 		Timeout:               30 * time.Second,
 		MaxResponseSize:       50 << 20,
 		MaxConnectionsPerHost: 20,
 		MaxConnections:        64,
 	})
 	exp := time.Now().Add(time.Hour)
 	expired := time.Now().Add(-time.Hour)
@@ -297,299 +264,3 @@ func TestHandleImage_AllowlistOrSignature(t *testing.T) {
 		})
 	}
 }
 // TestHandleImage_InvalidHost_Returns400 sends image URLs whose host no URL
 // host can be, and checks that each is refused with 400 naming the host as
 // decoded: allowlistedHost with a character after it that a URL host cannot
 // hold, percent-encoded, an IPv6 address without brackets, and brackets
 // around something that is not an IPv6 address. Later steps put the host
 // unparsed into the allowlist check, the cache key and the upstream URL, so
 // such a host is refused first.
 func TestHandleImage_InvalidHost_Returns400(t *testing.T) {
 	t.Parallel()
 	photos := newPhotoFetcher(t, allowlistedHost)
 	tests := []struct {
 		name        string
 		writtenHost string
 		decodedHost string
 	}{
 		{"? written as %3F", allowlistedHost + "%3Fx=1", allowlistedHost + "?x=1"},
 		{"# written as %23", allowlistedHost + "%23x", allowlistedHost + "#x"},
 		{"% written as %25", allowlistedHost + "%253F", allowlistedHost + "%3F"},
 		{`\ written as %5C`, allowlistedHost + "%5Cx", allowlistedHost + `\x`},
 		{"space written as %20", allowlistedHost + "%20", allowlistedHost + " "},
 		{"IPv6 address without brackets", "2001:db8::1", "2001:db8::1"},
 		{"IPv4 address in brackets", "[203.0.113.5]", "[203.0.113.5]"},
 		{"no address in brackets", "[abc]", "[abc]"},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			rec := sendGet(t, newImageRoute(t, photos), photoURL(tt.writtenHost))
 			checkErrorBody(t, rec, http.StatusBadRequest,
 				fmt.Sprintf("invalid image URL: invalid source host: %q",
 					tt.decodedHost))
 		})
 	}
 }
 // TestHandleImage_HostForms_Served checks that the image route serves, with
 // a valid signature, the image at photoPath on a host name, an IPv4 address,
 // an IPv6 address in brackets, and a host followed by ":" with or without a
 // port.
 func TestHandleImage_HostForms_Served(t *testing.T) {
 	t.Parallel()
 	hosts := []string{
 		allowlistedHost,
 		"img_1.example.com",
 		"203.0.113.5",
 		"[2001:db8::1]",
 		allowlistedHost + ":8443",
 		"[2001:db8::1]:8443",
 		allowlistedHost + ":",
 	}
 	photos := newPhotoFetcher(t, hosts...)
 	exp := time.Now().Add(time.Hour)
 	for _, host := range hosts {
 		t.Run(host, func(t *testing.T) {
 			t.Parallel()
 			sig := photoSignature(testSigningKey, host, exp)
 			rec := sendGet(t, newImageRoute(t, photos),
 				photoURLWithSig(host, sig, exp))
 			if rec.Code != http.StatusOK {
 				t.Errorf("status = %d, want %d: %s",
 					rec.Code, http.StatusOK, rec.Body)
 			}
 		})
 	}
 }
 // TestHandleImage_HashInSourcePathOrQuery_Returns400 sends image URLs whose
 // source path or source query holds a "#", written as %23, and checks that
 // each is refused with 400, the one signed for that source path included.
 // A "#" starts a URL's fragment, so neither the source path nor the source
 // query may hold one.
 func TestHandleImage_HashInSourcePathOrQuery_Returns400(t *testing.T) {
 	t.Parallel()
 	photos := newPhotoFetcher(t, allowlistedHost, signedHost)
 	exp := time.Now().Add(time.Hour)
 	sig := signature.New(testSigningKey).Sign(&imagerequest.Request{
 		Source: imagerequest.Source{
 			Host: signedHost,
 			Path: photoPath + "#x",
 		},
 		Transform: imagerequest.Transform{
 			Size:    imagerequest.Size{Width: 50, Height: 50},
 			Format:  imagerequest.FormatJPEG,
 			Quality: 85,
 			FitMode: imagerequest.FitCover,
 		},
 	}, exp)
 	tests := []struct {
 		name   string
 		target string
 	}{
 		{"# in the source path",
 			"/v1/image/" + allowlistedHost + photoPath + "%23x/50x50.jpeg"},
 		{"# in the source query",
 			"/v1/image/" + allowlistedHost + photoPath + "%3Fv=1%23x/50x50.jpeg"},
 		{"# in the source path, signed",
 			fmt.Sprintf("/v1/image/%s%s%%23x/50x50.jpeg?sig=%s&exp=%d",
 				signedHost, photoPath, sig, exp.Unix())},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			rec := sendGet(t, newImageRoute(t, photos), tt.target)
 			checkErrorBody(t, rec, http.StatusBadRequest,
 				`invalid image URL: invalid image path: `+
 					`the source path or query holds a "#"`)
 		})
 	}
 }
 // failingFetcher answers every fetch with its error.
 type failingFetcher struct {
 	err error
 }
 // Fetch returns f's error.
 func (f failingFetcher) Fetch(
 	context.Context, imagerequest.Source, string, string,
 ) (*httpfetcher.FetchResult, error) {
 	return nil, f.err
 }
 // photoURLsByRoute returns, for each image route, the function that makes the
 // URL of the JPEG at photoPath on signedHost on that route.
 func photoURLsByRoute() map[string]func(*testing.T, *Handlers) string {
 	return map[string]func(*testing.T, *Handlers) string{
 		"/v1/image/": signedPhotoURL,
 		"/v1/e/":     encPhotoURL,
 	}
 }
 // TestImageRoutes_SameErrorAnswers checks that both image routes answer each
 // upstream fetch error below with the same status. They log it as "failed to
 // get image" at the same level: error for the 500 and warn for the others.
 // Each request gets routes of its own, so no request finds another's failed
 // fetch in the negative cache.
 func TestImageRoutes_SameErrorAnswers(t *testing.T) {
 	t.Parallel()
 	tests := []struct {
 		name       string
 		err        error
 		wantStatus int
 		wantLevel  slog.Level
 	}{
 		{"blocked upstream address", httpfetcher.ErrSSRFBlocked,
 			http.StatusForbidden, slog.LevelWarn},
 		{"upstream error status",
 			fmt.Errorf("%w: status 404", httpfetcher.ErrUpstreamError),
 			http.StatusBadGateway, slog.LevelWarn},
 		{"upstream host with no address",
 			fmt.Errorf("%w: cdn.example.com", httpfetcher.ErrInvalidHost),
 			http.StatusBadGateway, slog.LevelWarn},
 		{"connection refused",
 			fmt.Errorf("%w: %w", httpfetcher.ErrUpstreamRequestFailed,
 				syscall.ECONNREFUSED),
 			http.StatusBadGateway, slog.LevelWarn},
 		{"no response headers within the fetch timeout",
 			httpfetcher.ErrUpstreamTimeout, http.StatusGatewayTimeout,
 			slog.LevelWarn},
 		{"no free upstream connection", httpfetcher.ErrTooManyConnections,
 			http.StatusServiceUnavailable, slog.LevelWarn},
 		{"Content-Type not a source format",
 			fmt.Errorf("%w: image/tiff", httpfetcher.ErrInvalidContentType),
 			http.StatusUnsupportedMediaType, slog.LevelWarn},
 		{"any other failure", io.ErrUnexpectedEOF,
 			http.StatusInternalServerError, slog.LevelError},
 	}
 	for _, tt := range tests {
 		for route, imageURL := range photoURLsByRoute() {
 			t.Run(route+" "+tt.name, func(t *testing.T) {
 				t.Parallel()
 				var logs bytes.Buffer
 				h, routes := newRoutesFetchingThrough(t,
 					failingFetcher{err: tt.err},
 					slog.New(slog.NewJSONHandler(&logs, nil)))
 				rec := sendGet(t, routes, imageURL(t, h))
 				if rec.Code != tt.wantStatus {
 					t.Errorf("status = %d, want %d: %s",
 						rec.Code, tt.wantStatus, rec.Body)
 				}
 				levels := loggedLevels(t, &logs)
 				if !slices.Contains(levels[tt.wantLevel.String()],
 					"failed to get image") {
 					t.Errorf(`no "failed to get image" line logged at level %s`,
 						tt.wantLevel)
 				}
 				if tt.wantLevel != slog.LevelError &&
 					len(levels[slog.LevelError.String()]) != 0 {
 					t.Errorf("logged at error level: %q",
 						levels[slog.LevelError.String()])
 				}
 			})
 		}
 	}
 }
 // failingResponseWriter is a response writer whose Write always fails, as when
 // the client has gone away.
 type failingResponseWriter struct {
 	*httptest.ResponseRecorder
 }
 // Write writes nothing and returns io.ErrClosedPipe.
 func (failingResponseWriter) Write([]byte) (int, error) {
 	return 0, io.ErrClosedPipe
 }
 // TestImageRoutes_FailedWriteLoggedOnce checks that both image routes log a
 // failed write of the image once, at warn level, with the request's ID, the
 // source host and path, the bytes served and the error. Neither may also log
 // the image as served.
 func TestImageRoutes_FailedWriteLoggedOnce(t *testing.T) {
 	t.Parallel()
 	const requestID = "test-request-id"
 	for route, imageURL := range photoURLsByRoute() {
 		t.Run(route, func(t *testing.T) {
 			t.Parallel()
 			var logs bytes.Buffer
 			h, srv := newSignedHostServer(t,
 				slog.New(slog.NewJSONHandler(&logs, nil)))
 			ctx := context.WithValue(t.Context(),
 				middleware.RequestIDKey, requestID)
 			srv.ServeHTTP(failingResponseWriter{httptest.NewRecorder()},
 				httptest.NewRequestWithContext(
 					ctx, http.MethodGet, imageURL(t, h), nil))
 			t.Logf("logged:\n%s", logs.String())
 			var failedWrites []map[string]any
 			dec := json.NewDecoder(&logs)
 			for dec.More() {
 				var line map[string]any
 				err := dec.Decode(&line)
 				if err != nil {
 					t.Fatalf("decoding log line: %v", err)
 				}
 				switch line["msg"] {
 				case "image served":
 					t.Error(`"image served" logged after a failed write`)
 				case "failed to write response":
 					failedWrites = append(failedWrites, line)
 				}
 			}
 			if len(failedWrites) != 1 {
 				t.Fatalf(`"failed to write response" logged %d times, want 1`,
 					len(failedWrites))
 			}
 			want := map[string]any{
 				"level":        slog.LevelWarn.String(),
 				"request_id":   requestID,
 				"host":         signedHost,
 				"path":         photoPath,
 				"served_bytes": float64(0),
 				"error":        io.ErrClosedPipe.Error(),
 			}
 			for key, wantValue := range want {
 				if got := failedWrites[0][key]; got != wantValue {
 					t.Errorf("%s = %v, want %v", key, got, wantValue)
 				}
 			}
 		})
 	}
 }
@@ -5,12 +5,11 @@ import (
 	"fmt"
 	"net/http"
 	"net/http/httptest"
 	"net/url"
 	"testing"
 	"time"
 	"github.com/go-chi/chi/v5"
-	"sneak.berlin/go/pixa/internal/imagerequest"
+	"sneak.berlin/go/pixa/internal/imgcache"
 	"sneak.berlin/go/pixa/internal/signature"
 )
@@ -37,47 +36,6 @@ func getImage(t *testing.T, fix *testFixtures, target string) int {
 	return rec.Code
 }
 // generateSignedURL returns the /v1/image/ URL of req, signed with key and
 // expiring after ttl. It signs a copy of req, so req itself is not changed.
 // An unset quality or fit in the copy is set to 85 or cover, the values the
 // route uses when a URL has no q or fit. The URL carries q and fit next to sig
 // and exp, so the route verifies it for the quality and fit it was signed
 // with.
 func generateSignedURL(
 	key string, req *imagerequest.Request, ttl time.Duration,
 ) string {
 	signed := *req
 	if signed.Transform.Quality == 0 {
 		signed.Transform.Quality = 85
 	}
 	if signed.Transform.FitMode == "" {
 		signed.Transform.FitMode = imagerequest.FitCover
 	}
 	expires := time.Now().Add(ttl)
 	sig := signature.New(key).Sign(&signed, expires)
 	// A source query follows the source path after a "?". The image route
 	// reads the path decoded once, so the whole path is written in Go's own
 	// percent-encoding of a URL path, which writes "?" as %3F and "%" as %25,
 	// and leaves "/", ";", ",", "=" and "&" as they are.
 	sourcePathAndQuery := signed.Source.Path
 	if signed.Source.Query != "" {
 		sourcePathAndQuery += "?" + signed.Source.Query
 	}
 	unescapedPath := fmt.Sprintf("/v1/image/%s%s/%dx%d.%s",
 		signed.Source.Host, sourcePathAndQuery,
 		signed.Transform.Size.Width, signed.Transform.Size.Height,
 		signed.Transform.Format)
 	return fmt.Sprintf("%s?sig=%s&exp=%d&q=%d&fit=%s",
 		(&url.URL{Path: unescapedPath}).EscapedPath(), sig, expires.Unix(),
 		signed.Transform.Quality, signed.Transform.FitMode)
 }
 // TestHandleImage_SignatureCoversQualityAndFit signs a URL for quality 85
 // and fit cover, the values the route uses when a URL has no q or fit, and
 // sends that signature with each q and fit below.
@@ -86,18 +44,16 @@ func TestHandleImage_SignatureCoversQualityAndFit(t *testing.T) {
 	expires := time.Now().Add(time.Hour)
 	signer := signature.New("test-signing-key-must-be-32-chars")
-	sig := signer.Sign(&imagerequest.Request{
+	sig := signer.Sign(&signature.Request{
-		Source: imagerequest.Source{
+		SourceHost: signedHost,
-			Host: signedHost,
+		SourcePath: "/images/photo.jpg",
-			Path: "/images/photo.jpg",
+		Width:      50,
-		},
+		Height:     50,
-		Transform: imagerequest.Transform{
+		Format:     string(imgcache.FormatJPEG),
 			Size:    imagerequest.Size{Width: 50, Height: 50},
 			Format:  imagerequest.FormatJPEG,
 		Quality:    85,
-			FitMode: imagerequest.FitCover,
+		FitMode:    string(imgcache.FitCover),
-		},
+		Expires:    expires,
-	}, expires)
+	})
 	signedURL := fmt.Sprintf("/v1/image/%s/images/photo.jpg/50x50.jpeg?sig=%s&exp=%d",
 		signedHost, sig, expires.Unix())
@@ -124,17 +80,17 @@ func TestHandleImage_SignatureCoversQualityAndFit(t *testing.T) {
 	}
 }
-// TestHandleImage_GeneratedSignedURLVerifies sends URLs built by
+// TestHandleImage_GeneratedSignedURLVerifies sends URLs built by the
-// generateSignedURL to the route.
+// service's signed-URL generator to the route.
 func TestHandleImage_GeneratedSignedURLVerifies(t *testing.T) {
 	t.Parallel()
 	tests := []struct {
 		name    string
 		quality int
-		fitMode imagerequest.Fit
+		fitMode imgcache.FitMode
 	}{
-		{"quality 40 and fit contain", 40, imagerequest.FitContain},
+		{"quality 40 and fit contain", 40, imgcache.FitContain},
 		{"quality and fit unset", 0, ""},
 	}
@@ -142,21 +98,21 @@ func TestHandleImage_GeneratedSignedURLVerifies(t *testing.T) {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
-			signedURL := generateSignedURL("test-signing-key-must-be-32-chars",
+			fix := setupTestHandler(t)
-				&imagerequest.Request{
+
-					Source: imagerequest.Source{
+			signedURL, err := fix.service.GenerateSignedURL("", &imgcache.ImageRequest{
-						Host: signedHost,
+				SourceHost: signedHost,
-						Path: "/images/photo.jpg",
+				SourcePath: "/images/photo.jpg",
-					},
+				Size:       imgcache.Size{Width: 50, Height: 50},
-					Transform: imagerequest.Transform{
+				Format:     imgcache.FormatJPEG,
 						Size:    imagerequest.Size{Width: 50, Height: 50},
 						Format:  imagerequest.FormatJPEG,
 				Quality:    tt.quality,
 				FitMode:    tt.fitMode,
 					},
 			}, time.Hour)
 			if err != nil {
 				t.Fatalf("GenerateSignedURL() error = %v", err)
 			}
-			status := getImage(t, setupTestHandler(t), signedURL)
+			status := getImage(t, fix, signedURL)
 			if status != http.StatusBadGateway {
 				t.Errorf("status = %d, want %d", status, http.StatusBadGateway)
 			}
@@ -213,170 +169,3 @@ func TestHandleImage_InvalidExp_Returns400(t *testing.T) {
 		})
 	}
 }
 // TestHandleImage_GeneratedSignedURLWithSourceQueryVerifies sends URLs built
 // by generateSignedURL for source URLs with a query to the route, through a
 // chi router: chi routes on the path as the client wrote it whenever that is
 // not Go's own encoding of it. A 502 means the signature passed, so the route
 // read the source path and query that were signed.
 func TestHandleImage_GeneratedSignedURLWithSourceQueryVerifies(t *testing.T) {
 	t.Parallel()
 	tests := []struct {
 		name  string
 		query string
 	}{
 		{"slash and colon", "url=https://origin.example.com/cat.jpg"},
 		{"semicolon", "a=1;b=2"},
 		{"comma", "crop=0,0,50,50"},
 		{"equals and ampersand", "a=1&b=2"},
 		{"percent-escape", "name=my%20cat"},
 		{"question mark", "next=/a?b=1"},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			signedURL := generateSignedURL("test-signing-key-must-be-32-chars",
 				&imagerequest.Request{
 					Source: imagerequest.Source{
 						Host:  signedHost,
 						Path:  photoPath,
 						Query: tt.query,
 					},
 					Transform: imagerequest.Transform{
 						Size:   imagerequest.Size{Width: 50, Height: 50},
 						Format: imagerequest.FormatJPEG,
 					},
 				}, time.Hour)
 			status := getImage(t, setupTestHandler(t), signedURL)
 			if status != http.StatusBadGateway {
 				t.Errorf("status = %d, want %d", status, http.StatusBadGateway)
 			}
 		})
 	}
 }
 // TestHandleImage_SourceQueryEncodedAnyWay signs one source URL with a query
 // and writes it into the image URL in ways the README allows: the "?" before
 // the query and each "%" in it percent-encoded, and every other character as
 // itself or percent-encoded. A 502 means the signature passed.
 func TestHandleImage_SourceQueryEncodedAnyWay(t *testing.T) {
 	t.Parallel()
 	expires := time.Now().Add(time.Hour)
 	signer := signature.New("test-signing-key-must-be-32-chars")
 	sig := signer.Sign(&imagerequest.Request{
 		Source: imagerequest.Source{
 			Host:  signedHost,
 			Path:  photoPath,
 			Query: "url=https://origin.example.com/my%20cat.jpg",
 		},
 		Transform: imagerequest.Transform{
 			Size:    imagerequest.Size{Width: 50, Height: 50},
 			Format:  imagerequest.FormatJPEG,
 			Quality: 85,
 			FitMode: imagerequest.FitCover,
 		},
 	}, expires)
 	tests := []struct {
 		name         string
 		writtenQuery string
 	}{
 		{"only ? and % encoded",
 			"%3Furl=https://origin.example.com/my%2520cat.jpg"},
 		{"every reserved character encoded",
 			"%3Furl%3Dhttps%3A%2F%2Forigin.example.com%2Fmy%2520cat.jpg"},
 		{"lower-case hex digits",
 			"%3furl=https://origin.example.com/my%2520cat.jpg"},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			target := fmt.Sprintf("/v1/image/%s%s%s/50x50.jpeg?sig=%s&exp=%d",
 				signedHost, photoPath, tt.writtenQuery, sig, expires.Unix())
 			status := getImage(t, setupTestHandler(t), target)
 			if status != http.StatusBadGateway {
 				t.Errorf("status = %d, want %d", status, http.StatusBadGateway)
 			}
 		})
 	}
 }
 // TestHandleImage_SourceURLHoldingPercent25Verifies signs a source path and a
 // source query that each hold %25, the percent-escape of a literal "%", and
 // sends each to the route written as the README says, with that "%" written as
 // %25, and as generateSignedURL writes it. A 502 means the signature passed.
 func TestHandleImage_SourceURLHoldingPercent25Verifies(t *testing.T) {
 	t.Parallel()
 	tests := []struct {
 		name        string
 		sourcePath  string
 		sourceQuery string
 		// writtenPathAndQuery is the source path and query as the README says
 		// to write them into the image URL
 		writtenPathAndQuery string
 	}{
 		{"path", "/sale/50%25off.jpg", "", "/sale/50%2525off.jpg"},
 		{"query", photoPath, "discount=50%25", photoPath + "%3Fdiscount=50%2525"},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name+" written by the README rule", func(t *testing.T) {
 			t.Parallel()
 			expires := time.Now().Add(time.Hour)
 			signer := signature.New("test-signing-key-must-be-32-chars")
 			sig := signer.Sign(&imagerequest.Request{
 				Source: imagerequest.Source{
 					Host:  signedHost,
 					Path:  tt.sourcePath,
 					Query: tt.sourceQuery,
 				},
 				Transform: imagerequest.Transform{
 					Size:    imagerequest.Size{Width: 50, Height: 50},
 					Format:  imagerequest.FormatJPEG,
 					Quality: 85,
 					FitMode: imagerequest.FitCover,
 				},
 			}, expires)
 			target := fmt.Sprintf("/v1/image/%s%s/50x50.jpeg?sig=%s&exp=%d",
 				signedHost, tt.writtenPathAndQuery, sig, expires.Unix())
 			status := getImage(t, setupTestHandler(t), target)
 			if status != http.StatusBadGateway {
 				t.Errorf("status = %d, want %d", status, http.StatusBadGateway)
 			}
 		})
 		t.Run(tt.name+" written by generateSignedURL", func(t *testing.T) {
 			t.Parallel()
 			signedURL := generateSignedURL("test-signing-key-must-be-32-chars",
 				&imagerequest.Request{
 					Source: imagerequest.Source{
 						Host:  signedHost,
 						Path:  tt.sourcePath,
 						Query: tt.sourceQuery,
 					},
 					Transform: imagerequest.Transform{
 						Size:   imagerequest.Size{Width: 50, Height: 50},
 						Format: imagerequest.FormatJPEG,
 					},
 				}, time.Hour)
 			status := getImage(t, setupTestHandler(t), signedURL)
 			if status != http.StatusBadGateway {
 				t.Errorf("status = %d, want %d", status, http.StatusBadGateway)
 			}
 		})
 	}
 }
@@ -2,13 +2,19 @@ package handlers
 import (
 	"errors"
 	"fmt"
 	"io"
 	"net/http"
 	"strconv"
 	"time"
 	"github.com/go-chi/chi/v5"
 	"github.com/go-chi/chi/v5/middleware"
 	"sneak.berlin/go/pixa/internal/encurl"
-	"sneak.berlin/go/pixa/internal/imagerequest"
+	"sneak.berlin/go/pixa/internal/httpfetcher"
 	"sneak.berlin/go/pixa/internal/imageprocessor"
 	"sneak.berlin/go/pixa/internal/imgcache"
 )
 // HandleImageEnc handles requests to /v1/e/{token}/* for encrypted
@@ -20,59 +26,152 @@ func (s *Handlers) HandleImageEnc() http.HandlerFunc {
 			return
 		}
-		req, expires, ok := s.parseImageEncRequest(w, r)
+		ctx := r.Context()
-		if !ok {
+		start := time.Now()
 		req, ok := s.parseImageEncRequest(w, r)
 		if !ok || !s.chooseAutoFormat(w, r, req) {
 			return
 		}
-		s.serveImage(w, r, req, expires)
+		// Log the request
 		s.log.Debug("encrypted image request",
 			"host", req.SourceHost,
 			"path", req.SourcePath,
 			"dimensions", fmt.Sprintf("%dx%d", req.Size.Width, req.Size.Height),
 			"format", req.Format,
 		)
 		// Fetch and process the image (no signature validation
 		// needed - encrypted URL is trusted)
 		resp, err := s.imgSvc.Get(ctx, req)
 		if err != nil {
 			s.handleImageError(w, err)
 			return
 		}
 		defer func() { _ = resp.Content.Close() }()
 		// Set response headers
 		w.Header().Set("Content-Type", resp.ContentType)
 		if resp.ContentLength > 0 {
 			w.Header().Set("Content-Length", strconv.FormatInt(resp.ContentLength, 10))
 		}
 		// Cache headers: max-age ends at the URL's expiry
 		w.Header().Set("Cache-Control", cacheControl(req.Expires))
 		w.Header().Set("X-Pixa-Cache", string(resp.CacheStatus))
 		if notModified(w, r, resp.ETag) {
 			return
 		}
 		// A HEAD request gets the headers only
 		if r.Method == http.MethodHead {
 			w.WriteHeader(http.StatusOK)
 			return
 		}
 		// Stream the response
 		written, err := io.Copy(w, resp.Content)
 		if err != nil {
 			s.log.Error("failed to write response", "error", err)
 			return
 		}
 		// Log completion
 		duration := time.Since(start)
 		s.log.Info("image served",
 			"request_id", middleware.GetReqID(ctx),
 			"cache_key", imgcache.CacheKey(req),
 			"host", req.SourceHost,
 			"path", req.SourcePath,
 			"format", req.Format,
 			"cache_status", resp.CacheStatus,
 			"served_bytes", written,
 			"duration_ms", duration.Milliseconds(),
 		)
 	}
 }
 // parseImageEncRequest decrypts the token of an encrypted image URL into an
-// image request and checks it, and returns it with the token's expiry. On a
+// ImageRequest and checks it. On a token that is missing, does not decrypt,
-// token that is missing, does not decrypt, has expired or asks for something
+// has expired or asks for something not valid, it writes an error response
-// not valid, it writes an error response and returns false.
+// and returns false.
 func (s *Handlers) parseImageEncRequest(
 	w http.ResponseWriter, r *http.Request,
-) (*imagerequest.Request, time.Time, bool) {
+) (*imgcache.ImageRequest, bool) {
 	// Extract token from URL
 	token := chi.URLParam(r, "token")
 	if token == "" {
 		s.respondError(w, "missing token", http.StatusBadRequest)
-		return nil, time.Time{}, false
+		return nil, false
 	}
 	// Decrypt and validate the payload
-	req, expires, err := s.encGen.Parse(token)
+	payload, err := s.encGen.Parse(token)
 	if err != nil {
 		if errors.Is(err, encurl.ErrExpired) {
 			s.log.Debug("encrypted URL expired", "error", err)
 			s.respondError(w, "URL has expired", http.StatusGone)
-			return nil, time.Time{}, false
+			return nil, false
 		}
-		s.log.Debug("invalid encrypted URL", "error", err)
+		s.log.Debug("failed to decrypt URL", "error", err)
 		s.respondError(w, "invalid encrypted URL", http.StatusBadRequest)
-		return nil, time.Time{}, false
+		return nil, false
 	}
 	// Convert payload to ImageRequest
 	req := payload.ToImageRequest()
 	// Apply the same dimension and fit-mode bounds as the plain image
 	// route: a sealed payload is trusted for its origin, not for staying
-	// within limits. This refuses an over-limit size before the source is
+	// within limits, so an over-limit size or unknown fit mode is a 400
-	// fetched. An unknown fit mode is a 400 here rather than a 500 from the
+	// here rather than an out-of-memory or a 500 from the processor.
-	// processor.
+	err = imgcache.ValidateImageRequest(req)
 	err = imagerequest.ValidateImageRequest(req)
 	if err != nil {
 		s.log.Debug("encrypted URL failed validation", "error", err)
 		s.respondError(w, "invalid encrypted URL: "+err.Error(),
 			http.StatusBadRequest)
-		return nil, time.Time{}, false
+		return nil, false
 	}
-	return req, expires, true
+	return req, true
 }
 // handleImageError converts image service errors to HTTP responses.
 func (s *Handlers) handleImageError(w http.ResponseWriter, err error) {
 	switch {
 	case errors.Is(err, httpfetcher.ErrSSRFBlocked):
 		s.respondError(w, "forbidden", http.StatusForbidden)
 	case errors.Is(err, httpfetcher.ErrUpstreamError):
 		s.respondError(w, "upstream error", http.StatusBadGateway)
 	case errors.Is(err, httpfetcher.ErrUpstreamTimeout):
 		s.respondError(w, "upstream timeout", http.StatusGatewayTimeout)
 	case errors.Is(err, httpfetcher.ErrTooManyConnections),
 		errors.Is(err, imageprocessor.ErrTooManyImages),
 		errors.Is(err, imgcache.ErrProcessingTimedOut):
 		s.respondError(w, "server busy, try again later",
 			http.StatusServiceUnavailable)
 	case errors.Is(err, httpfetcher.ErrInvalidContentType),
 		errors.Is(err, imageprocessor.ErrUnsupportedInputFormat):
 		s.respondError(w, "unsupported source format",
 			http.StatusUnsupportedMediaType)
 	case errors.Is(err, imageprocessor.ErrOutputTooLarge):
 		s.respondError(w, fmt.Sprintf("size too large for the source: the side "+
 			"computed from its proportions is above %d",
 			imageprocessor.MaxOutputDimension), http.StatusBadRequest)
 	default:
 		s.log.Error("image request failed", "error", err)
 		s.respondError(w, "internal error", http.StatusInternalServerError)
 	}
 }
@@ -6,13 +6,11 @@ import (
 	"net/http"
 	"net/http/httptest"
 	"testing"
 	"time"
 	"github.com/go-chi/chi/v5"
 	"sneak.berlin/go/pixa/internal/encurl"
-	"sneak.berlin/go/pixa/internal/imagerequest"
+	"sneak.berlin/go/pixa/internal/imgcache"
 	"sneak.berlin/go/pixa/internal/seal"
 )
 // newEncTestServer builds a router serving the encrypted-URL route with a
@@ -22,13 +20,11 @@ import (
 func newEncTestServer(t *testing.T) (*encurl.Generator, http.Handler) {
 	t.Helper()
-	keys, err := seal.DeriveKeys(testSigningKey)
+	encGen, err := encurl.NewGenerator(testSigningKey)
 	if err != nil {
-		t.Fatalf("seal.DeriveKeys() error = %v", err)
+		t.Fatalf("encurl.NewGenerator() error = %v", err)
 	}
 	encGen := encurl.NewGenerator(keys.EncryptedURLKey)
 	h := &Handlers{
 		log:    slog.New(slog.DiscardHandler),
 		encGen: encGen,
@@ -58,15 +54,12 @@ func TestHandleImageEnc_OverLimitDimension_Returns400(t *testing.T) {
 	encGen, srv := newEncTestServer(t)
-	token, err := encGen.Generate(&imagerequest.Request{
+	token, err := encGen.Generate(&encurl.Payload{
-		Source: imagerequest.Source{
+		SourceHost: "cdn.example.com",
-			Host: "cdn.example.com",
+		SourcePath: "/photo.jpg",
-			Path: "/photo.jpg",
+		Width:      100000,
-		},
+		Height:     100000,
-		Transform: imagerequest.Transform{
+	})
 			Size: imagerequest.Size{Width: 100000, Height: 100000},
 		},
 	}, time.Time{})
 	if err != nil {
 		t.Fatalf("Generate() error = %v", err)
 	}
@@ -86,16 +79,13 @@ func TestHandleImageEnc_InvalidFitMode_Returns400(t *testing.T) {
 	encGen, srv := newEncTestServer(t)
-	token, err := encGen.Generate(&imagerequest.Request{
+	token, err := encGen.Generate(&encurl.Payload{
-		Source: imagerequest.Source{
+		SourceHost: "cdn.example.com",
-			Host: "cdn.example.com",
+		SourcePath: "/photo.jpg",
-			Path: "/photo.jpg",
+		Width:      800,
-		},
+		Height:     600,
-		Transform: imagerequest.Transform{
+		FitMode:    imgcache.FitMode("bogus"),
-			Size:    imagerequest.Size{Width: 800, Height: 600},
+	})
 			FitMode: imagerequest.Fit("bogus"),
 		},
 	}, time.Time{})
 	if err != nil {
 		t.Fatalf("Generate() error = %v", err)
 	}
@@ -9,8 +9,6 @@ import (
 	"time"
 	"sneak.berlin/go/pixa/internal/encurl"
 	"sneak.berlin/go/pixa/internal/imagerequest"
 	"sneak.berlin/go/pixa/internal/seal"
 )
 // requireServedPhoto requires that rec answers 200 with the JPEG at photoPath
@@ -61,34 +59,32 @@ func TestHandleImageEnc_RejectedToken(t *testing.T) {
 	h, srv := newSignedHostServer(t, slog.New(slog.DiscardHandler))
-	photo := imagerequest.Request{
+	photo := encurl.Payload{
-		Source: imagerequest.Source{
+		SourceHost: signedHost,
-			Host: signedHost,
+		SourcePath: photoPath,
-			Path: photoPath,
+		Width:      50,
-		},
+		Height:     50,
 		Transform: imagerequest.Transform{
 			Size: imagerequest.Size{Width: 50, Height: 50},
 		},
 	}
-	valid, err := h.encGen.Generate(&photo, time.Time{})
+	valid, err := h.encGen.Generate(&photo)
 	if err != nil {
 		t.Fatalf("Generate() error = %v", err)
 	}
-	expired, err := h.encGen.Generate(&photo, time.Now().Add(-time.Minute))
+	expiredPhoto := photo
 	expiredPhoto.ExpiresAt = time.Now().Add(-time.Minute).Unix()
 	expired, err := h.encGen.Generate(&expiredPhoto)
 	if err != nil {
 		t.Fatalf("Generate() error = %v", err)
 	}
-	keys, err := seal.DeriveKeys("another-signing-key-fedcba9876543210")
+	otherGen, err := encurl.NewGenerator("another-signing-key-fedcba9876543210")
 	if err != nil {
-		t.Fatalf("seal.DeriveKeys() error = %v", err)
+		t.Fatalf("encurl.NewGenerator() error = %v", err)
 	}
-	otherGen := encurl.NewGenerator(keys.EncryptedURLKey)
+	otherKey, err := otherGen.Generate(&photo)
 	otherKey, err := otherGen.Generate(&photo, time.Time{})
 	if err != nil {
 		t.Fatalf("Generate() error = %v", err)
 	}
@@ -14,7 +14,7 @@ import (
 	"github.com/davidbyttow/govips/v2/vips"
 	"sneak.berlin/go/pixa/internal/encurl"
-	"sneak.berlin/go/pixa/internal/imagerequest"
+	"sneak.berlin/go/pixa/internal/imgcache"
 	"sneak.berlin/go/pixa/internal/signature"
 )
@@ -58,18 +58,16 @@ func TestImageWithoutFormat_SignedAsJXL(t *testing.T) {
 	route := newImageRoute(t, newPhotoFetcher(t, signedHost))
 	expires := time.Now().Add(time.Hour)
-	sig := signature.New(testSigningKey).Sign(&imagerequest.Request{
+	sig := signature.New(testSigningKey).Sign(&signature.Request{
-		Source: imagerequest.Source{
+		SourceHost: signedHost,
-			Host: signedHost,
+		SourcePath: photoPath,
-			Path: photoPath,
+		Width:      50,
-		},
+		Height:     50,
-		Transform: imagerequest.Transform{
+		Format:     string(imgcache.FormatJXL),
 			Size:    imagerequest.Size{Width: 50, Height: 50},
 			Format:  imagerequest.FormatJXL,
 		Quality:    encurl.DefaultQuality,
-			FitMode: imagerequest.FitCover,
+		FitMode:    string(imgcache.FitCover),
-		},
+		Expires:    expires,
-	}, expires)
+	})
 	query := fmt.Sprintf("?sig=%s&exp=%d", sig, expires.Unix())
 	for _, size := range []string{"50x50.jxl", "50x50"} {
@@ -85,15 +83,12 @@ func TestImageEncWithoutFormat_ServesJPEGXL(t *testing.T) {
 	h, srv := newSignedHostServer(t, slog.New(slog.DiscardHandler))
-	token, err := h.encGen.Generate(&imagerequest.Request{
+	token, err := h.encGen.Generate(&encurl.Payload{
-		Source: imagerequest.Source{
+		SourceHost: signedHost,
-			Host: signedHost,
+		SourcePath: photoPath,
-			Path: photoPath,
+		Width:      50,
-		},
+		Height:     50,
-		Transform: imagerequest.Transform{
+	})
 			Size: imagerequest.Size{Width: 50, Height: 50},
 		},
 	}, time.Time{})
 	if err != nil {
 		t.Fatalf("Generate() error = %v", err)
 	}
@@ -7,7 +7,7 @@ import (
 	"github.com/davidbyttow/govips/v2/vips"
-	"sneak.berlin/go/pixa/internal/imagerequest"
+	"sneak.berlin/go/pixa/internal/imgcache"
 )
 // jxlType is the content type of JPEG XL.
@@ -22,14 +22,14 @@ func TestFormatForAccept_JPEGXL(t *testing.T) {
 	tests := []struct {
 		name   string
 		accept string
-		want   imagerequest.Format
+		want   imgcache.ImageFormat
 	}{
 		{"JPEG XL-capable browser",
-			"image/jxl,image/avif,image/webp,image/*,*/*;q=0.8", imagerequest.FormatJXL},
+			"image/jxl,image/avif,image/webp,image/*,*/*;q=0.8", imgcache.FormatJXL},
-		{"JPEG XL only", jxlType, imagerequest.FormatJXL},
+		{"JPEG XL only", jxlType, imgcache.FormatJXL},
 		{"JPEG XL with a lower q than AVIF", "image/avif,image/jxl;q=0.5",
-			imagerequest.FormatJXL},
+			imgcache.FormatJXL},
-		{"q=0 on JPEG XL", "image/jxl;q=0,image/avif,*/*", imagerequest.FormatAVIF},
+		{"q=0 on JPEG XL", "image/jxl;q=0,image/avif,*/*", imgcache.FormatAVIF},
 	}
 	for _, tt := range tests {
@@ -10,16 +10,10 @@ import (
 	"time"
 	"github.com/go-chi/chi/v5"
 	"github.com/prometheus/client_golang/prometheus"
 	"sneak.berlin/go/pixa/internal/allowlist"
 	"sneak.berlin/go/pixa/internal/encurl"
 	"sneak.berlin/go/pixa/internal/httpfetcher"
 	"sneak.berlin/go/pixa/internal/imageprocessor"
 	"sneak.berlin/go/pixa/internal/imageproxy"
 	"sneak.berlin/go/pixa/internal/imagerequest"
 	"sneak.berlin/go/pixa/internal/imgcache"
 	"sneak.berlin/go/pixa/internal/seal"
 	"sneak.berlin/go/pixa/internal/signature"
 )
 // blockedReferer is a page on leech.example, which newRefererRoutes puts on
@@ -35,12 +29,11 @@ type countingFetcher struct {
 // Fetch counts the fetch and passes it on.
 func (f *countingFetcher) Fetch(
-	ctx context.Context, source imagerequest.Source,
+	ctx context.Context, url string,
 	ifNoneMatch, ifModifiedSince string,
 ) (*httpfetcher.FetchResult, error) {
 	f.fetches.Add(1)
-	return f.Fetcher.Fetch(ctx, source, ifNoneMatch, ifModifiedSince)
+	return f.Fetcher.Fetch(ctx, url)
 }
 // newRefererRoutes returns both image routes of a Handlers whose
@@ -54,41 +47,33 @@ func newRefererRoutes(t *testing.T) (http.Handler, *Handlers, *countingFetcher)
 		Fetcher: newPhotoFetcher(t, allowlistedHost, signedHost),
 	}
-	cache, err := imgcache.NewCache(setupTestDB(t), imgcache.Config{
+	cache, err := imgcache.NewCache(setupTestDB(t), imgcache.CacheConfig{
 		StateDir:    t.TempDir(),
 		NegativeTTL: 5 * time.Minute,
-		MaxBytes:    1 << 30,
+	})
 	}, prometheus.NewRegistry())
 	if err != nil {
 		t.Fatalf("imgcache.NewCache() error = %v", err)
 	}
-	svc, err := imageproxy.New(&imageproxy.Config{
+	svc, err := imgcache.NewService(&imgcache.ServiceConfig{
 		Cache:      cache,
 		Fetcher:    fetcher,
-		Processor: imageprocessor.New(imageprocessor.Params{
+		SigningKey: testSigningKey,
-			MaxInputBytes:           50 << 20,
+		Allowlist:  []string{allowlistedHost},
-			MaxConcurrentProcessing: 2,
+	})
 		}),
 		MaxResponseSize: 50 << 20,
 	}, prometheus.NewRegistry())
 	if err != nil {
-		t.Fatalf("imageproxy.New() error = %v", err)
+		t.Fatalf("imgcache.NewService() error = %v", err)
 	}
-	keys, err := seal.DeriveKeys(testSigningKey)
+	encGen, err := encurl.NewGenerator(testSigningKey)
 	if err != nil {
-		t.Fatalf("seal.DeriveKeys() error = %v", err)
+		t.Fatalf("encurl.NewGenerator() error = %v", err)
 	}
 	encGen := encurl.NewGenerator(keys.EncryptedURLKey)
 	h := &Handlers{
 		log:    slog.New(slog.DiscardHandler),
 		imgSvc: svc,
 		encGen: encGen,
 		signer:    signature.New(testSigningKey),
 		allowlist: allowlist.New([]string{allowlistedHost}),
 		refererBlocklist: allowlist.New(
 			[]string{"leech.example", ".hotlinker.example"}),
 	}
@@ -13,26 +13,26 @@ import (
 	"github.com/go-chi/chi/v5/middleware"
-	"sneak.berlin/go/pixa/internal/imagerequest"
+	"sneak.berlin/go/pixa/internal/encurl"
 	"sneak.berlin/go/pixa/internal/imgcache"
 )
 // signedPhotoURL returns a signed /v1/image/ URL, valid for a minute, for the
-// JPEG at photoPath on signedHost at 50x50. It is signed with testSigningKey,
+// JPEG at photoPath on signedHost at 50x50, made with h's image service.
-// the key the handlers that newSignedHostServer builds check signatures with.
+func signedPhotoURL(t *testing.T, h *Handlers) string {
 // It takes a Handlers it does not use, so that it has the type of encPhotoURL.
 func signedPhotoURL(t *testing.T, _ *Handlers) string {
 	t.Helper()
-	return generateSignedURL(testSigningKey, &imagerequest.Request{
+	signedURL, err := h.imgSvc.GenerateSignedURL("", &imgcache.ImageRequest{
-		Source: imagerequest.Source{
+		SourceHost: signedHost,
-			Host: signedHost,
+		SourcePath: photoPath,
-			Path: photoPath,
+		Size:       imgcache.Size{Width: 50, Height: 50},
-		},
+		Format:     imgcache.FormatJPEG,
 		Transform: imagerequest.Transform{
 			Size:   imagerequest.Size{Width: 50, Height: 50},
 			Format: imagerequest.FormatJPEG,
 		},
 	}, time.Minute)
 	if err != nil {
 		t.Fatalf("GenerateSignedURL() error = %v", err)
 	}
 	return signedURL
 }
 // encPhotoURL returns an encrypted /v1/e/ URL, which never expires, for the
@@ -40,16 +40,13 @@ func signedPhotoURL(t *testing.T, _ *Handlers) string {
 func encPhotoURL(t *testing.T, h *Handlers) string {
 	t.Helper()
-	token, err := h.encGen.Generate(&imagerequest.Request{
+	token, err := h.encGen.Generate(&encurl.Payload{
-		Source: imagerequest.Source{
+		SourceHost: signedHost,
-			Host: signedHost,
+		SourcePath: photoPath,
-			Path: photoPath,
+		Width:      50,
-		},
+		Height:     50,
-		Transform: imagerequest.Transform{
+		Format:     imgcache.FormatJPEG,
-			Size:   imagerequest.Size{Width: 50, Height: 50},
+	})
 			Format: imagerequest.FormatJPEG,
 		},
 	}, time.Time{})
 	if err != nil {
 		t.Fatalf("Generate() error = %v", err)
 	}
@@ -11,64 +11,77 @@ import (
 	"sneak.berlin/go/pixa/internal/httpfetcher"
 	"sneak.berlin/go/pixa/internal/imageprocessor"
-	"sneak.berlin/go/pixa/internal/imageproxy"
+	"sneak.berlin/go/pixa/internal/imgcache"
 	"sneak.berlin/go/pixa/internal/imagerequest"
 )
-// TestServerBusyAnswers503 checks that respondImageError, which answers the
+// TestServerBusyAnswers503 checks that both image routes answer 503 with
-// errors of both image routes, answers 503 with a clear error when the image
+// a clear error when the image service gives up waiting for a free upstream
-// service gives up waiting for a free upstream connection or processing slot,
+// connection or processing slot, wrapped as the service wraps them.
 // wrapped as the service wraps them.
 func TestServerBusyAnswers503(t *testing.T) {
 	t.Parallel()
 	h := &Handlers{log: slog.New(slog.DiscardHandler)}
-	req := &imagerequest.Request{
+	req := &imgcache.ImageRequest{SourceHost: "img.example.com", SourcePath: "/a.jpg"}
 		Source: imagerequest.Source{Host: "img.example.com", Path: "/a.jpg"},
 	}
 	for _, err := range []error{
 		fmt.Errorf("upstream fetch failed: %w", httpfetcher.ErrTooManyConnections),
 		fmt.Errorf("image processing failed: %w", imageprocessor.ErrTooManyImages),
 	} {
-		rec := httptest.NewRecorder()
+		plain := httptest.NewRecorder()
-		h.respondImageError(rec, req, err)
+		h.respondImageError(plain, req, err)
 		encrypted := httptest.NewRecorder()
 		h.handleImageError(encrypted, err)
 		for route, rec := range map[string]*httptest.ResponseRecorder{
 			"/v1/image/": plain, "/v1/e/": encrypted,
 		} {
 			if rec.Code != http.StatusServiceUnavailable {
-			t.Errorf("for %v: status = %d, want %d",
+				t.Errorf("%s for %v: status = %d, want %d",
-				err, rec.Code, http.StatusServiceUnavailable)
+					route, err, rec.Code, http.StatusServiceUnavailable)
 			}
 			if !strings.Contains(rec.Body.String(), "server busy, try again later") {
-			t.Errorf("for %v: body = %q, want the server busy error",
+				t.Errorf("%s for %v: body = %q, want the server busy error",
-				err, rec.Body.String())
+					route, err, rec.Body.String())
 			}
 		}
 	}
 }
-// TestProcessingTimedOutAnswers503 checks that respondImageError, which
+// TestProcessingTimedOutAnswers503 checks that respondImageError and
-// answers the errors of both image routes, answers 503 with the server busy
+// handleImageError, which answer the errors of the two image routes, answer
-// error when the image service reports that processing stopped at the
+// 503 with the server busy error when the image service reports that
-// deadline of the request doing it, wrapped as the service wraps it. A request
+// processing stopped at the deadline of the request doing it, wrapped as the
-// that waited for that processing gets this error while its own deadline may
+// service wraps it. A request that waited for that processing gets this error
-// have time left. The request's source only goes into a log line, so it is
+// while its own deadline may have time left. The request's source only goes
-// left empty.
+// into a log line, so it is left empty.
 func TestProcessingTimedOutAnswers503(t *testing.T) {
 	t.Parallel()
 	h := &Handlers{log: slog.New(slog.DiscardHandler)}
 	err := fmt.Errorf("%w: failed to encode: %w",
-		imageproxy.ErrProcessingTimedOut, context.DeadlineExceeded)
+		imgcache.ErrProcessingTimedOut, context.DeadlineExceeded)
-	rec := httptest.NewRecorder()
+	plain := httptest.NewRecorder()
-	h.respondImageError(rec, &imagerequest.Request{}, err)
+	h.respondImageError(plain, &imgcache.ImageRequest{}, err)
-	t.Logf("status = %d, body = %q", rec.Code, rec.Body.String())
+
 	encrypted := httptest.NewRecorder()
 	h.handleImageError(encrypted, err)
 	for name, rec := range map[string]*httptest.ResponseRecorder{
 		"respondImageError": plain, "handleImageError": encrypted,
 	} {
 		t.Logf("%s: status = %d, body = %q", name, rec.Code, rec.Body.String())
 		if rec.Code != http.StatusServiceUnavailable {
-		t.Errorf("status = %d, want %d", rec.Code, http.StatusServiceUnavailable)
+			t.Errorf("%s: status = %d, want %d",
 				name, rec.Code, http.StatusServiceUnavailable)
 		}
 		if !strings.Contains(rec.Body.String(), "server busy, try again later") {
-		t.Errorf("body = %q, want the server busy error", rec.Body.String())
+			t.Errorf("%s: body = %q, want the server busy error",
 				name, rec.Body.String())
 		}
 	}
 }
@@ -10,104 +10,45 @@ import (
 	"sneak.berlin/go/pixa/internal/httpfetcher"
 	"sneak.berlin/go/pixa/internal/imageprocessor"
-	"sneak.berlin/go/pixa/internal/imagerequest"
+	"sneak.berlin/go/pixa/internal/imgcache"
 )
-// TestUnsupportedSourceFormatAnswers415 checks that respondImageError, which
+// TestUnsupportedSourceFormatAnswers415 checks that both image routes answer
-// answers the errors of both image routes, answers 415 with a clear error when
+// 415 with a clear error when the upstream answers with a content type pixa
-// the upstream answers with a content type pixa does not accept, such as TIFF,
+// does not accept, such as SVG, and when orig is asked of a source in a
-// and when libvips does not read a source as the format its first bytes
+// format the processor cannot name, wrapped as the service wraps them.
 // show, wrapped as the service wraps them.
 func TestUnsupportedSourceFormatAnswers415(t *testing.T) {
 	t.Parallel()
 	h := &Handlers{log: slog.New(slog.DiscardHandler)}
-	req := &imagerequest.Request{
+	req := &imgcache.ImageRequest{SourceHost: "img.example.com", SourcePath: "/a.svg"}
 		Source: imagerequest.Source{Host: "img.example.com", Path: "/a.tiff"},
 	}
 	for _, err := range []error{
-		fmt.Errorf("upstream fetch failed: %w: image/tiff",
+		fmt.Errorf("upstream fetch failed: %w: image/svg+xml",
 			httpfetcher.ErrInvalidContentType),
-		fmt.Errorf("image processing failed: %w: libvips does not read the input as avif",
+		fmt.Errorf("image processing failed: %w: unknown",
 			imageprocessor.ErrUnsupportedInputFormat),
 	} {
-		rec := httptest.NewRecorder()
+		plain := httptest.NewRecorder()
-		h.respondImageError(rec, req, err)
+		h.respondImageError(plain, req, err)
-		t.Logf("for %v: %d %s", err, rec.Code, rec.Body.String())
+
 		encrypted := httptest.NewRecorder()
 		h.handleImageError(encrypted, err)
 		for route, rec := range map[string]*httptest.ResponseRecorder{
 			"HandleImage": plain, "HandleImageEnc": encrypted,
 		} {
 			t.Logf("%s for %v: %d %s", route, err, rec.Code, rec.Body.String())
 			if rec.Code != http.StatusUnsupportedMediaType {
-			t.Errorf("for %v: status = %d, want %d",
+				t.Errorf("%s for %v: status = %d, want %d",
-				err, rec.Code, http.StatusUnsupportedMediaType)
+					route, err, rec.Code, http.StatusUnsupportedMediaType)
 			}
 			if !strings.Contains(rec.Body.String(), "unsupported source format") {
-			t.Errorf("for %v: body = %q, want the unsupported source format error",
+				t.Errorf("%s for %v: body = %q, want the unsupported source format error",
-				err, rec.Body.String())
+					route, err, rec.Body.String())
 			}
 		}
 	}
 }
 // TestSVGTooThinAnswers415 checks that respondImageError answers 415 with a
 // clear error for an SVG source too thin to render, wrapped as the service
 // wraps it.
 func TestSVGTooThinAnswers415(t *testing.T) {
 	t.Parallel()
 	h := &Handlers{log: slog.New(slog.DiscardHandler)}
 	req := &imagerequest.Request{
 		Source: imagerequest.Source{Host: "svg.example.com", Path: "/a.svg"},
 	}
 	err := fmt.Errorf("image processing failed: %w: 81930x10",
 		imageprocessor.ErrSVGTooThin)
 	rec := httptest.NewRecorder()
 	h.respondImageError(rec, req, err)
 	t.Logf("for %v: %d %s", err, rec.Code, rec.Body.String())
 	if rec.Code != http.StatusUnsupportedMediaType {
 		t.Errorf("status = %d, want %d", rec.Code,
 			http.StatusUnsupportedMediaType)
 	}
 	if !strings.Contains(rec.Body.String(), "SVG source too thin to render") {
 		t.Errorf("body = %q, want the SVG too thin error", rec.Body.String())
 	}
 }
 // TestSVGRenderFailedAnswers415 checks that respondImageError answers 415,
 // naming the limits, for an SVG source that a child process could not read
 // or render, wrapped as the service wraps it.
 func TestSVGRenderFailedAnswers415(t *testing.T) {
 	t.Parallel()
 	h := &Handlers{log: slog.New(slog.DiscardHandler)}
 	err := fmt.Errorf("image processing failed: %w: it took more than 20s",
 		imageprocessor.ErrSVGRenderFailed)
 	rec := httptest.NewRecorder()
 	h.respondImageError(rec, &imagerequest.Request{}, err)
 	t.Logf("for %v: %d %s", err, rec.Code, rec.Body.String())
 	checkErrorBody(t, rec, http.StatusUnsupportedMediaType,
 		"SVG source could not be rendered: it is not valid, or it takes more "+
 			"than 20 seconds or 1 GiB of memory to render")
 }
 // TestSVGTooLargeForOrigSizeAnswers400 checks that respondImageError answers
 // 400, asking for a size, for an SVG source above 8192 on a side asked for at
 // the orig size in a raster format, wrapped as the service wraps it.
 func TestSVGTooLargeForOrigSizeAnswers400(t *testing.T) {
 	t.Parallel()
 	h := &Handlers{log: slog.New(slog.DiscardHandler)}
 	err := fmt.Errorf("image processing failed: %w: 10000x10 is above 8192",
 		imageprocessor.ErrSVGTooLargeForOrigSize)
 	rec := httptest.NewRecorder()
 	h.respondImageError(rec, &imagerequest.Request{}, err)
 	t.Logf("for %v: %d %s", err, rec.Code, rec.Body.String())
 	checkErrorBody(t, rec, http.StatusBadRequest,
 		"SVG source above 8192 on a side: give a size to render it at")
 }
@@ -1,211 +0,0 @@
 package handlers
 import (
 	"testing"
 	"time"
 	"sneak.berlin/go/pixa/internal/allowlist"
 	"sneak.berlin/go/pixa/internal/signature"
 )
 // Addresses the port tests below put on the allowlist.
 const (
 	allowlistedIPv4 = "203.0.113.5"
 	allowlistedIPv6 = "2001:db8::1"
 )
 // newSignatureChecker returns Handlers that check signatures with
 // testSigningKey and have allowlistHosts on their allowlist, as New builds
 // them from signing_key and allowlist_hosts.
 func newSignatureChecker(allowlistHosts ...string) *Handlers {
 	return &Handlers{
 		signer:    signature.New(testSigningKey),
 		allowlist: allowlist.New(allowlistHosts),
 	}
 }
 func TestValidateSignature_NonAllowlistedHost_NoSignature(t *testing.T) {
 	t.Parallel()
 	h := newSignatureChecker(allowlistedHost)
 	// Should fail validation - not allowlisted and no signature
 	err := h.validateSignature(photoRequest(signedHost), "", time.Time{})
 	if err == nil {
 		t.Error("validateSignature() expected error for non-allowlisted " +
 			"host without signature")
 	}
 }
 func TestValidateSignature_NonAllowlistedHost_ValidSignature(t *testing.T) {
 	t.Parallel()
 	h := newSignatureChecker(allowlistedHost)
 	req := photoRequest(signedHost)
 	// Generate a valid signature
 	expires := time.Now().Add(time.Hour)
 	sig := signature.New(testSigningKey).Sign(req, expires)
 	// Should pass validation
 	err := h.validateSignature(req, sig, expires)
 	if err != nil {
 		t.Errorf("validateSignature() error = %v", err)
 	}
 }
 func TestValidateSignature_NonAllowlistedHost_ExpiredSignature(t *testing.T) {
 	t.Parallel()
 	h := newSignatureChecker(allowlistedHost)
 	req := photoRequest(signedHost)
 	// Generate an expired signature
 	expires := time.Now().Add(-time.Hour)
 	sig := signature.New(testSigningKey).Sign(req, expires)
 	// Should fail validation
 	err := h.validateSignature(req, sig, expires)
 	if err == nil {
 		t.Error("validateSignature() expected error for expired signature")
 	}
 }
 func TestValidateSignature_NonAllowlistedHost_InvalidSignature(t *testing.T) {
 	t.Parallel()
 	h := newSignatureChecker(allowlistedHost)
 	// Should fail validation
 	err := h.validateSignature(photoRequest(signedHost), "invalid-signature",
 		time.Now().Add(time.Hour))
 	if err == nil {
 		t.Error("validateSignature() expected error for invalid signature")
 	}
 }
 // TestValidateSignature_NoAllowlist checks that with no host on the
 // allowlist, a request without a signature fails validation.
 func TestValidateSignature_NoAllowlist(t *testing.T) {
 	t.Parallel()
 	h := newSignatureChecker()
 	err := h.validateSignature(photoRequest(signedHost), "", time.Time{})
 	if err == nil {
 		t.Error("validateSignature() expected error when no host is allowlisted")
 	}
 }
 // TestValidateSignature_SignatureExactHostMatch verifies that
 // validateSignature enforces exact host matching for signatures. A
 // signature for one host must not verify for a different host, even
 // if they share a domain suffix.
 func TestValidateSignature_SignatureExactHostMatch(t *testing.T) {
 	t.Parallel()
 	h := newSignatureChecker()
 	// Sign a request for signedHost
 	signedReq := photoRequest(signedHost)
 	expires := time.Now().Add(time.Hour)
 	sig := signature.New(testSigningKey).Sign(signedReq, expires)
 	// The original request should pass validation
 	t.Run("exact host passes", func(t *testing.T) {
 		t.Parallel()
 		err := h.validateSignature(signedReq, sig, expires)
 		if err != nil {
 			t.Errorf("validateSignature() exact host failed: %v", err)
 		}
 	})
 	// Try to reuse the signature with different hosts
 	tests := []struct {
 		name string
 		host string
 	}{
 		{"parent domain", "example.com"},
 		{"sibling subdomain", "images.example.com"},
 		{"deeper subdomain", "a." + signedHost},
 		{"evil suffix domain", signedHost + ".evil.com"},
 		{"prefixed host", "evil" + signedHost},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name+" rejected", func(t *testing.T) {
 			t.Parallel()
 			err := h.validateSignature(photoRequest(tt.host), sig, expires)
 			if err == nil {
 				t.Errorf("validateSignature() should reject signature for "+
 					"host %q (signed for %q)", tt.host, signedHost)
 			}
 		})
 	}
 }
 // TestValidateSignature_HostWithPortNeedsSignature verifies that a host
 // followed by a port, or by a colon with no port, matches no allowlist entry,
 // so that a request for it without a signature is refused, while the same
 // host with no port is allowlisted.
 func TestValidateSignature_HostWithPortNeedsSignature(t *testing.T) {
 	t.Parallel()
 	h := newSignatureChecker(allowlistedHost, allowlistedIPv4, allowlistedIPv6)
 	tests := []struct {
 		host        string
 		allowlisted bool
 	}{
 		{allowlistedHost, true},
 		{allowlistedHost + ":8443", false},
 		{allowlistedHost + ":443", false},
 		{allowlistedHost + ":", false},
 		{allowlistedIPv4, true},
 		{allowlistedIPv4 + ":8080", false},
 		{"[" + allowlistedIPv6 + "]", true},
 		{"[" + allowlistedIPv6 + "]:8443", false},
 	}
 	for _, tt := range tests {
 		t.Run(tt.host, func(t *testing.T) {
 			t.Parallel()
 			err := h.validateSignature(photoRequest(tt.host), "", time.Time{})
 			t.Logf("validateSignature() for host %q with no signature: %v",
 				tt.host, err)
 			if allowlisted := err == nil; allowlisted != tt.allowlisted {
 				t.Errorf("host %q served without a signature = %v, want %v",
 					tt.host, allowlisted, tt.allowlisted)
 			}
 		})
 	}
 }
 // TestValidateSignature_UnbracketedIPv6PortNeedsSignature verifies that an
 // allowlisted IPv6 address written without brackets and followed by a port,
 // or by a colon with no port, needs a signature. Go's URL type reads
 // 2001:db8::1:8443 as the host 2001:db8::1 with the port 8443.
 func TestValidateSignature_UnbracketedIPv6PortNeedsSignature(t *testing.T) {
 	t.Parallel()
 	h := newSignatureChecker(allowlistedIPv6)
 	for _, host := range []string{allowlistedIPv6 + ":8443", allowlistedIPv6 + ":"} {
 		t.Run(host, func(t *testing.T) {
 			t.Parallel()
 			err := h.validateSignature(photoRequest(host), "", time.Time{})
 			t.Logf("validateSignature() for host %q with no signature: %v",
 				host, err)
 			if err == nil {
 				t.Errorf("host %q served without a signature, want refused",
 					host)
 			}
 		})
 	}
 }
@@ -7,7 +7,6 @@ import (
 	"net/http"
 	"net/netip"
 	"testing"
 	"time"
 )
 // TestIsPrivateIPBlocksSpecialRanges covers the internal and special-use
@@ -71,15 +70,12 @@ func transportOf(t *testing.T, f *HTTPFetcher) *http.Transport {
 func TestDialerEnforcesBlockedNetworks(t *testing.T) {
 	t.Parallel()
-	transport := transportOf(t, New(&Config{
+	cfg := DefaultConfig()
 		Timeout:               30 * time.Second,
 		MaxResponseSize:       50 << 20,
 		MaxConnectionsPerHost: 20,
 		MaxConnections:        64,
 	// TEST-NET-2 (198.51.100.0/24) is public to the built-in check, so
 	// blocking it can only come from the operator-supplied list.
-		BlockedNetworks: []netip.Prefix{netip.MustParsePrefix("198.51.100.0/24")},
+	cfg.BlockedNetworks = []netip.Prefix{netip.MustParsePrefix("198.51.100.0/24")}
-	}))
+
 	transport := transportOf(t, New(cfg))
 	blocked := []string{
 		"198.51.100.5:80", // operator-supplied range
@@ -1,76 +0,0 @@
 package httpfetcher
 import (
 	"errors"
 	"io"
 	"net/http"
 	"net/http/httptest"
 	"sync"
 	"testing"
 )
 // TestFetch_SendsConditionalHeadersAndHandlesNotModified checks that Fetch
 // sends a non-empty ifNoneMatch and ifModifiedSince as request headers, that
 // upstream's 304 to such a request is a result with status 304 and no
 // content, and that a 304 to a request with neither is ErrUpstreamError.
 func TestFetch_SendsConditionalHeadersAndHandlesNotModified(t *testing.T) {
 	t.Parallel()
 	const (
 		etag         = `"abc"`
 		lastModified = "Mon, 02 Nov 2026 10:00:00 GMT"
 	)
 	var (
 		mu       sync.Mutex
 		received http.Header
 	)
 	srv := httptest.NewServer(http.HandlerFunc(
 		func(w http.ResponseWriter, r *http.Request) {
 			mu.Lock()
 			received = r.Header.Clone()
 			mu.Unlock()
 			w.WriteHeader(http.StatusNotModified)
 		}))
 	t.Cleanup(srv.Close)
 	f, _ := newServerFetcher(t, srv, nil)
 	res, err := f.Fetch(testContext(t), upstreamSource("/image"), etag, lastModified)
 	if err != nil {
 		t.Fatalf("conditional Fetch() error = %v", err)
 	}
 	body, err := io.ReadAll(res.Content)
 	_ = res.Content.Close()
 	mu.Lock()
 	t.Logf("status = %d, body = %q, request headers = %v", res.StatusCode, body, received)
 	gotIfNoneMatch := received.Get("If-None-Match")
 	gotIfModifiedSince := received.Get("If-Modified-Since")
 	mu.Unlock()
 	if err != nil || len(body) != 0 {
 		t.Errorf("304 content = %q, error = %v; want empty", body, err)
 	}
 	if res.StatusCode != http.StatusNotModified {
 		t.Errorf("StatusCode = %d, want 304", res.StatusCode)
 	}
 	if gotIfNoneMatch != etag || gotIfModifiedSince != lastModified {
 		t.Errorf("If-None-Match = %q, If-Modified-Since = %q; want %q and %q",
 			gotIfNoneMatch, gotIfModifiedSince, etag, lastModified)
 	}
 	if held := len(f.allHostsSemaphore); held != 0 {
 		t.Errorf("connection still held after the 304: %d held", held)
 	}
 	_, err = f.Fetch(testContext(t), upstreamSource("/image"), "", "")
 	if !errors.Is(err, ErrUpstreamError) {
 		t.Errorf("unconditional Fetch() answered 304: error = %v, want ErrUpstreamError", err)
 	}
 }
@@ -4,7 +4,6 @@ import (
 	"errors"
 	"net"
 	"testing"
 	"time"
 )
 // TestNewUsesCheckedDialerWithoutDialContext checks that a fetcher built
@@ -14,12 +13,7 @@ func TestNewUsesCheckedDialerWithoutDialContext(t *testing.T) {
 	t.Parallel()
 	srv := startUpstream(t)
-	transport := transportOf(t, New(&Config{
+	transport := transportOf(t, New(DefaultConfig()))
 		Timeout:               30 * time.Second,
 		MaxResponseSize:       50 << 20,
 		MaxConnectionsPerHost: 20,
 		MaxConnections:        64,
 	}))
 	addr := srv.Listener.Addr().String()
@@ -38,25 +32,21 @@ func TestDialContextReplacesOnlyTheDialer(t *testing.T) {
 	srv := startUpstream(t)
 	dialer := &recordingDialer{target: srv.Listener.Addr().String()}
-	f := New(&Config{
+	cfg := DefaultConfig()
-		Timeout:               30 * time.Second,
+	cfg.AllowHTTP = true
-		MaxResponseSize:       50 << 20,
+	cfg.DialContext = dialer.dialContext
-		AllowHTTP:             true,
+	f := New(cfg)
 		MaxConnectionsPerHost: 20,
 		MaxConnections:        64,
 		DialContext:           dialer.dialContext,
 	})
 	if body := fetchBody(t, f, "/image"); body != imagePayload {
 		t.Errorf("body = %q, want %q", body, imagePayload)
 	}
-	_, err := f.Fetch(testContext(t), imageSourceOn("127.0.0.1"), "", "")
+	_, err := f.Fetch(testContext(t), "http://127.0.0.1/image")
 	if !errors.Is(err, ErrSSRFBlocked) {
 		t.Errorf("Fetch(loopback URL) error = %v, want ErrSSRFBlocked", err)
 	}
-	_, err = f.Fetch(testContext(t), upstreamSource("/redirect/private"), "", "")
+	_, err = f.Fetch(testContext(t), upstreamURL("/redirect/private"))
 	if !errors.Is(err, ErrSSRFBlocked) {
 		t.Errorf("Fetch(/redirect/private) error = %v, want ErrSSRFBlocked", err)
 	}
@@ -14,8 +14,6 @@ import (
 	"sync"
 	"testing"
 	"time"
 	"sneak.berlin/go/pixa/internal/imagerequest"
 )
 // testPublicHost is a TEST-NET-1 (RFC 5737) literal. isPrivateIP treats it as
@@ -31,9 +29,9 @@ const imagePayload = "fake-jpeg-bytes"
 // would mean SSRF protection let a forbidden target reach the transport.
 var errUnexpectedDial = errors.New("unexpected dial target")
-// upstreamSource returns the source at path on the fake public host.
+// upstreamURL builds a fetch URL on the fake public host for the given path.
-func upstreamSource(path string) imagerequest.Source {
+func upstreamURL(path string) string {
-	return imagerequest.Source{Host: testPublicHost, Path: path}
+	return "http://" + testPublicHost + path
 }
 // recordingDialer records every address the transport asks it to dial and
@@ -83,7 +81,7 @@ func startUpstream(t *testing.T) *httptest.Server {
 	mux := http.NewServeMux()
 	mux.HandleFunc("/image", func(w http.ResponseWriter, _ *http.Request) {
-		w.Header().Set("Content-Type", imagerequest.FormatJPEG.MIMEType())
+		w.Header().Set("Content-Type", contentTypeJPEG)
 		_, _ = io.WriteString(w, imagePayload)
 	})
 	mux.HandleFunc("/status/500", func(w http.ResponseWriter, _ *http.Request) {
@@ -122,12 +120,7 @@ func newServerFetcher(
 	t.Helper()
 	if cfg == nil {
-		cfg = &Config{
+		cfg = DefaultConfig()
 			Timeout:               30 * time.Second,
 			MaxResponseSize:       50 << 20,
 			MaxConnectionsPerHost: 20,
 			MaxConnections:        64,
 		}
 	}
 	cfg.AllowHTTP = true
@@ -160,7 +153,7 @@ func testContext(t *testing.T) context.Context {
 func fetchImage(t *testing.T, f *HTTPFetcher, path string) *FetchResult {
 	t.Helper()
-	res, err := f.Fetch(testContext(t), upstreamSource(path), "", "")
+	res, err := f.Fetch(testContext(t), upstreamURL(path))
 	if err != nil {
 		t.Fatalf("Fetch(%s) error = %v", path, err)
 	}
@@ -172,7 +165,7 @@ func fetchImage(t *testing.T, f *HTTPFetcher, path string) *FetchResult {
 func fetchExpectError(t *testing.T, f *HTTPFetcher, path string) error {
 	t.Helper()
-	res, err := f.Fetch(testContext(t), upstreamSource(path), "", "")
+	res, err := f.Fetch(testContext(t), upstreamURL(path))
 	if err == nil {
 		_ = res.Content.Close()
@@ -224,7 +217,7 @@ func TestFetchRedirectToPrivateIPBlocked(t *testing.T) {
 	srv := startUpstream(t)
 	f, dialer := newServerFetcher(t, srv, nil)
-	_, err := f.Fetch(testContext(t), upstreamSource("/redirect/private"), "", "")
+	_, err := f.Fetch(testContext(t), upstreamURL("/redirect/private"))
 	if !errors.Is(err, ErrSSRFBlocked) {
 		t.Fatalf("Fetch() error = %v, want ErrSSRFBlocked", err)
 	}
@@ -287,12 +280,8 @@ func TestFetchMaxResponseSizeEnforced(t *testing.T) {
 	srv := startUpstream(t)
-	cfg := &Config{
+	cfg := DefaultConfig()
-		Timeout:               30 * time.Second,
+	cfg.MaxResponseSize = 8
 		MaxResponseSize:       8,
 		MaxConnectionsPerHost: 20,
 		MaxConnections:        64,
 	}
 	f, _ := newServerFetcher(t, srv, cfg)
@@ -321,12 +310,8 @@ func fetchWithMaxResponseSize(
 	srv := httptest.NewServer(handler)
 	t.Cleanup(srv.Close)
-	cfg := &Config{
+	cfg := DefaultConfig()
-		Timeout:               30 * time.Second,
+	cfg.MaxResponseSize = maxResponseSize
 		MaxResponseSize:       maxResponseSize,
 		MaxConnectionsPerHost: 20,
 		MaxConnections:        64,
 	}
 	f, _ := newServerFetcher(t, srv, cfg)
@@ -358,7 +343,7 @@ func TestFetchContentLengthBodyAtMaxResponseSize(t *testing.T) {
 			res := fetchWithMaxResponseSize(t, maxResponseSize,
 				func(w http.ResponseWriter, _ *http.Request) {
-					w.Header().Set("Content-Type", imagerequest.FormatJPEG.MIMEType())
+					w.Header().Set("Content-Type", contentTypeJPEG)
 					w.Header().Set("Content-Length", strconv.Itoa(tc.size))
 					_, _ = io.WriteString(w, body)
 				})
@@ -406,7 +391,7 @@ func TestFetchChunkedBodyAtMaxResponseSize(t *testing.T) {
 			res := fetchWithMaxResponseSize(t, maxResponseSize,
 				func(w http.ResponseWriter, r *http.Request) {
-					w.Header().Set("Content-Type", imagerequest.FormatJPEG.MIMEType())
+					w.Header().Set("Content-Type", contentTypeJPEG)
 					_, _ = io.WriteString(w, body)
 					// With no Content-Length, flushing sends the body
 					// chunked; its end is sent when the handler returns.
@@ -451,12 +436,8 @@ func TestFetchSemaphoreReleasedOnError(t *testing.T) {
 	srv := startUpstream(t)
-	cfg := &Config{
+	cfg := DefaultConfig()
-		Timeout:               30 * time.Second,
+	cfg.MaxConnectionsPerHost = 1
 		MaxResponseSize:       50 << 20,
 		MaxConnectionsPerHost: 1,
 		MaxConnections:        64,
 	}
 	f, _ := newServerFetcher(t, srv, cfg)
@@ -485,12 +466,8 @@ func assertSlotReleasedByClose(
 	srv := startUpstream(t)
-	cfg := &Config{
+	cfg := DefaultConfig()
-		Timeout:               30 * time.Second,
+	cfg.MaxConnectionsPerHost = 1
 		MaxResponseSize:       50 << 20,
 		MaxConnectionsPerHost: 1,
 		MaxConnections:        64,
 	}
 	f, _ := newServerFetcher(t, srv, cfg)
@@ -547,7 +524,7 @@ func TestFetchSemaphoreReleasedOnPartialReadClose(t *testing.T) {
 	})
 }
-// The dial-time re-resolution in dialSSRFSafe is what closes the DNS
+// The dial-time re-resolution in ssrfSafeDialer is what closes the DNS
 // rebinding window: even if validateURL saw a public answer earlier, the
 // dialer independently re-checks the address it is about to connect to. A full
 // rebinding simulation (a resolver returning public, then private) would mean
@@ -567,9 +544,9 @@ func TestSSRFSafeDialerBlocksPrivateTarget(t *testing.T) {
 		t.Run(addr, func(t *testing.T) {
 			t.Parallel()
-			_, err := dialSSRFSafe(context.Background(), "tcp", addr, nil)
+			_, err := ssrfSafeDialer(context.Background(), "tcp", addr)
 			if !errors.Is(err, ErrSSRFBlocked) {
-				t.Errorf("dialSSRFSafe(%q) = %v, want ErrSSRFBlocked", addr, err)
+				t.Errorf("ssrfSafeDialer(%q) = %v, want ErrSSRFBlocked", addr, err)
 			}
 		})
 	}
@@ -583,7 +560,7 @@ func TestSSRFSafeDialerAllowsPublicTarget(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	cancel()
-	_, err := dialSSRFSafe(ctx, "tcp", testPublicHost+":80", nil)
+	_, err := ssrfSafeDialer(ctx, "tcp", testPublicHost+":80")
 	if err == nil {
 		t.Fatal("expected a dial error for an unreachable public target")
 	}
@@ -592,53 +569,3 @@ func TestSSRFSafeDialerAllowsPublicTarget(t *testing.T) {
 		t.Errorf("public target was SSRF-blocked: %v", err)
 	}
 }
 // TestFetchSchemeFollowsAllowHTTP checks that the fetcher fetches a source
 // over https, on port 443, unless AllowHTTP is set, and then over http, on
 // port 80. The test server speaks plain HTTP, so only the fetch over http
 // succeeds.
 func TestFetchSchemeFollowsAllowHTTP(t *testing.T) {
 	t.Parallel()
 	tests := []struct {
 		allowHTTP bool
 		wantAddr  string
 	}{
 		{false, net.JoinHostPort(testPublicHost, "443")},
 		{true, net.JoinHostPort(testPublicHost, "80")},
 	}
 	for _, tt := range tests {
 		t.Run(fmt.Sprintf("AllowHTTP %v", tt.allowHTTP), func(t *testing.T) {
 			t.Parallel()
 			srv := startUpstream(t)
 			dialer := &recordingDialer{target: srv.Listener.Addr().String()}
 			f := New(&Config{
 				Timeout:               30 * time.Second,
 				MaxResponseSize:       50 << 20,
 				AllowHTTP:             tt.allowHTTP,
 				MaxConnectionsPerHost: 20,
 				MaxConnections:        64,
 				DialContext:           dialer.dialContext,
 			})
 			res, err := f.Fetch(testContext(t), upstreamSource("/image"), "", "")
 			if err == nil {
 				_ = res.Content.Close()
 			}
 			dialed := dialer.dialedAddrs()
 			t.Logf("Fetch(): error %v, dialed %v", err, dialed)
 			if served := err == nil; served != tt.allowHTTP {
 				t.Errorf("served = %v, want %v", served, tt.allowHTTP)
 			}
 			if len(dialed) != 1 || dialed[0] != tt.wantAddr {
 				t.Errorf("dialed %v, want only %s", dialed, tt.wantAddr)
 			}
 		})
 	}
 }
@@ -20,24 +20,36 @@ import (
 	"time"
 	"github.com/go-chi/chi/v5/middleware"
 	"sneak.berlin/go/pixa/internal/imagerequest"
 )
 // Fetcher configuration constants.
 const (
 	DefaultFetchTimeout          = 30 * time.Second
 	DefaultMaxResponseSize       = 50 << 20 // 50MB
 	DefaultTLSTimeout            = 10 * time.Second
 	DefaultMaxIdleConns          = 100
 	DefaultIdleConnTimeout       = 90 * time.Second
 	DefaultMaxRedirects          = 10
 	DefaultMaxConnectionsPerHost = 20
 	DefaultMaxConnections        = 64
 )
 // userAgent is the User-Agent header sent to upstream servers.
 const userAgent = "pixa/1.0"
 // ConnectionWaitTimeout is how long Fetch waits for a free connection when
 // MaxConnections fetches are already in progress.
 const ConnectionWaitTimeout = 10 * time.Second
 // MIME content types.
 const (
 	contentTypeJPEG        = "image/jpeg"
 	contentTypePNG         = "image/png"
 	contentTypeGIF         = "image/gif"
 	contentTypeWebP        = "image/webp"
 	contentTypeAVIF        = "image/avif"
 	contentTypeJXL         = "image/jxl"
 	contentTypeSVG         = "image/svg+xml"
 	contentTypeOctetStream = "application/octet-stream"
 )
 // Loopback addresses blocked by SSRF protection.
 const (
 	localhostIPv4 = "127.0.0.1"
@@ -47,9 +59,8 @@ const (
 // builtinBlockedPrefixes are internal or special-use ranges that Go's
 // net.IP predicates (IsPrivate, IsLinkLocalUnicast, and the like) do not
 // already cover. They are always blocked, in addition to any
-// operator-supplied networks. IPv4-mapped and IPv4-compatible IPv6
+// operator-supplied networks. IPv4-mapped IPv6 addresses are unmapped
-// addresses are read as the IPv4 address they hold before matching, so
+// before matching, so these IPv4 ranges are caught in both forms.
 // these IPv4 ranges are caught in all three forms.
 //
 //nolint:gochecknoglobals // immutable built-in blocklist
 var builtinBlockedPrefixes = []netip.Prefix{
@@ -57,7 +68,6 @@ var builtinBlockedPrefixes = []netip.Prefix{
 	netip.MustParsePrefix("192.0.0.0/24"),  // RFC 6890 IETF protocol assignments
 	netip.MustParsePrefix("198.18.0.0/15"), // RFC 2544 benchmarking range
 	netip.MustParsePrefix("64:ff9b::/96"),  // RFC 6052 NAT64 (maps onto IPv4)
 	netip.MustParsePrefix("64:ff9b:1::/48"), // RFC 8215 local-use NAT64 (maps onto IPv4)
 }
 // Fetcher errors.
@@ -69,10 +79,6 @@ var (
 	ErrInvalidContentType = errors.New("invalid or unsupported content type")
 	ErrUpstreamError      = errors.New("upstream server error")
 	ErrUpstreamTimeout    = errors.New("upstream request timeout")
 	// ErrUpstreamRequestFailed is a fetch that failed before the upstream
 	// answered, other than by timeout or cancellation: a failed connection
 	// or TLS handshake, or a redirect the fetcher refuses.
 	ErrUpstreamRequestFailed = errors.New("upstream request failed")
 	ErrTooManyConnections = errors.New("too many concurrent upstream connections")
 )
@@ -84,13 +90,8 @@ var (
 // Fetcher retrieves content from upstream origins.
 type Fetcher interface {
-	// Fetch retrieves the content of the source image. A non-empty
+	// Fetch retrieves content from the given URL.
-	// ifNoneMatch or ifModifiedSince is sent as the request header of that
+	Fetch(ctx context.Context, url string) (*FetchResult, error)
 	// name, and upstream may then answer 304 Not Modified with no content.
 	Fetch(
 		ctx context.Context, source imagerequest.Source,
 		ifNoneMatch, ifModifiedSince string,
 	) (*FetchResult, error)
 }
 // FetchResult contains the result of fetching from upstream.
@@ -117,30 +118,17 @@ type FetchResult struct {
 	TLSCipherSuite string
 }
-// allowedContentTypes returns the content types an upstream response may
+// Config holds configuration for the upstream fetcher.
 // have, which Fetch also sends as its Accept header: the MIME types of the
 // formats pixa reads.
 func allowedContentTypes() []string {
 	return []string{
 		imagerequest.FormatJPEG.MIMEType(),
 		imagerequest.FormatPNG.MIMEType(),
 		imagerequest.FormatGIF.MIMEType(),
 		imagerequest.FormatWebP.MIMEType(),
 		imagerequest.FormatAVIF.MIMEType(),
 		imagerequest.FormatJXL.MIMEType(),
 		imagerequest.FormatSVG.MIMEType(),
 	}
 }
 // Config holds configuration for the upstream fetcher. Every field but
 // AllowHTTP, BlockedNetworks and DialContext must be set.
 type Config struct {
 	// Timeout for upstream requests.
 	Timeout time.Duration
 	// MaxResponseSize is the maximum allowed response body size.
 	MaxResponseSize int64
-	// AllowHTTP makes the fetcher fetch sources over http instead of https,
+	// UserAgent to send to upstream servers.
-	// and follow redirects to http (for testing only).
+	UserAgent string
 	// AllowedContentTypes is an allow list of MIME types to accept.
 	AllowedContentTypes []string
 	// AllowHTTP allows non-TLS connections (for testing only).
 	AllowHTTP bool
 	// MaxConnectionsPerHost limits concurrent connections to each upstream host.
 	MaxConnectionsPerHost int
@@ -157,6 +145,26 @@ type Config struct {
 	DialContext func(ctx context.Context, network, addr string) (net.Conn, error)
 }
 // DefaultConfig returns a Config with sensible defaults.
 func DefaultConfig() *Config {
 	return &Config{
 		Timeout:         DefaultFetchTimeout,
 		MaxResponseSize: DefaultMaxResponseSize,
 		UserAgent:       "pixa/1.0",
 		AllowedContentTypes: []string{
 			contentTypeJPEG,
 			contentTypePNG,
 			contentTypeGIF,
 			contentTypeWebP,
 			contentTypeAVIF,
 			contentTypeJXL,
 		},
 		AllowHTTP:             false,
 		MaxConnectionsPerHost: DefaultMaxConnectionsPerHost,
 		MaxConnections:        DefaultMaxConnections,
 	}
 }
 // HTTPFetcher implements Fetcher with SSRF protection and connection limits
 // per host and for all hosts together.
 type HTTPFetcher struct {
@@ -184,6 +192,10 @@ type hostSemaphore struct {
 // New creates a new HTTPFetcher with SSRF protection.
 func New(config *Config) *HTTPFetcher {
 	if config == nil {
 		config = DefaultConfig()
 	}
 	// Unless config.DialContext replaces it, the transport connects with
 	// the SSRF-safe dialer, which re-resolves and re-checks at connect time
 	// (closing the DNS-rebinding window) against both the built-in ranges
@@ -212,7 +224,7 @@ func New(config *Config) *HTTPFetcher {
 			}
 			// Validate the redirect target
-			err := validateURL(req.Context(), req.URL, config.AllowHTTP)
+			err := validateURL(req.Context(), req.URL.String(), config.AllowHTTP)
 			if err != nil {
 				return fmt.Errorf("redirect blocked: %w", err)
 			}
@@ -230,26 +242,18 @@ func New(config *Config) *HTTPFetcher {
 	}
 }
-// Fetch retrieves the source image with SSRF protection, over https, or over
+// Fetch retrieves content from the given URL with SSRF protection. When
-// http when AllowHTTP is set. When MaxConnections fetches are already in
+// MaxConnections fetches are already in progress, it waits up to
-// progress, it waits up to ConnectionWaitTimeout for one to finish, then
+// ConnectionWaitTimeout for one to finish, then fails with
-// fails with ErrTooManyConnections. A non-empty ifNoneMatch or
+// ErrTooManyConnections.
-// ifModifiedSince is sent as the If-None-Match or If-Modified-Since header.
+func (f *HTTPFetcher) Fetch(ctx context.Context, url string) (*FetchResult, error) {
 // Upstream's 304 Not Modified to such a request is a result with StatusCode
 // 304 and empty Content; to any other request it is ErrUpstreamError.
 func (f *HTTPFetcher) Fetch(
 	ctx context.Context, source imagerequest.Source,
 	ifNoneMatch, ifModifiedSince string,
 ) (*FetchResult, error) {
 	sourceURL := source.URL(f.config.AllowHTTP)
 	// Validate URL before making request
-	err := validateURL(ctx, sourceURL, f.config.AllowHTTP)
+	err := validateURL(ctx, url, f.config.AllowHTTP)
 	if err != nil {
 		return nil, err
 	}
-	release, err := f.acquireConnection(ctx, source.Host)
+	release, err := f.acquireConnection(ctx, extractHost(url))
 	if err != nil {
 		return nil, err
 	}
@@ -263,10 +267,25 @@ func (f *HTTPFetcher) Fetch(
 		}
 	}()
 	parsedURL, err := neturl.Parse(url)
 	if err != nil {
 		return nil, fmt.Errorf("failed to parse URL: %w", err)
 	}
 	req := &http.Request{
 		Method: http.MethodGet,
-		URL:    sourceURL,
+		URL:    parsedURL,
-		Header: requestHeaders(ctx, ifNoneMatch, ifModifiedSince),
+		Header: make(http.Header),
 	}
 	req.Header.Set("User-Agent", f.config.UserAgent)
 	req.Header.Set("Accept", strings.Join(f.config.AllowedContentTypes, ", "))
 	// The ID of the request this fetch serves, so the fetch can be found in
 	// the upstream host's logs
 	requestID := middleware.GetReqID(ctx)
 	if requestID != "" {
 		req.Header.Set(middleware.RequestIDHeader, requestID)
 	}
 	// Use httptrace to capture connection details
@@ -288,21 +307,11 @@ func (f *HTTPFetcher) Fetch(
 	fetchDuration := time.Since(startTime)
 	if err != nil {
-		return nil, upstreamRequestError(err)
+		if errors.Is(err, context.DeadlineExceeded) {
 			return nil, ErrUpstreamTimeout
 		}
-	// The deferred release gives the connection back, as no body follows
+		return nil, fmt.Errorf("upstream request failed: %w", err)
 	conditional := ifNoneMatch != "" || ifModifiedSince != ""
 	if conditional && resp.StatusCode == http.StatusNotModified {
 		_ = resp.Body.Close()
 		return &FetchResult{
 			Content:         http.NoBody,
 			Headers:         resp.Header,
 			StatusCode:      resp.StatusCode,
 			FetchDurationMs: fetchDuration.Milliseconds(),
 			RemoteAddr:      remoteAddr,
 		}, nil
 	}
 	result, err := f.buildResult(resp, remoteAddr, fetchDuration, release)
@@ -317,60 +326,6 @@ func (f *HTTPFetcher) Fetch(
 	return result, nil
 }
 // upstreamRequestError returns the error Fetch reports when its upstream
 // request fails with err:
 //   - err wrapped in ErrUpstreamTimeout for a timeout, so the log names what
 //     timed out.
 //   - err, still matching context.Canceled, when the caller cancelled the
 //     fetch.
 //   - err wrapped in ErrUpstreamRequestFailed otherwise.
 func upstreamRequestError(err error) error {
 	var netErr net.Error
 	switch {
 	case errors.Is(err, context.DeadlineExceeded),
 		errors.Is(err, ErrUpstreamTimeout),
 		errors.As(err, &netErr) && netErr.Timeout():
 		// A timeout other than the fetch timeout, such as the TLS
 		// handshake timeout, does not match context.DeadlineExceeded. An
 		// address lookup or a connection that timed out is
 		// ErrUpstreamTimeout already, so its log line names that error twice.
 		return fmt.Errorf("%w: %w", ErrUpstreamTimeout, err)
 	case errors.Is(err, context.Canceled):
 		// The caller cancelled the fetch; the upstream did not fail
 		return fmt.Errorf("upstream request cancelled: %w", err)
 	default:
 		return fmt.Errorf("%w: %w", ErrUpstreamRequestFailed, err)
 	}
 }
 // requestHeaders returns the headers of a fetch: User-Agent, Accept, the
 // ID of the request the fetch serves, so the fetch can be found in the
 // upstream host's logs, and a non-empty ifNoneMatch or ifModifiedSince.
 func requestHeaders(
 	ctx context.Context, ifNoneMatch, ifModifiedSince string,
 ) http.Header {
 	header := make(http.Header)
 	header.Set("User-Agent", userAgent)
 	header.Set("Accept", strings.Join(allowedContentTypes(), ", "))
 	requestID := middleware.GetReqID(ctx)
 	if requestID != "" {
 		header.Set(middleware.RequestIDHeader, requestID)
 	}
 	if ifNoneMatch != "" {
 		header.Set("If-None-Match", ifNoneMatch)
 	}
 	if ifModifiedSince != "" {
 		header.Set("If-Modified-Since", ifModifiedSince)
 	}
 	return header
 }
 // acquireConnection takes a slot for host, then one of the slots shared by
 // all hosts, and returns the func that gives both back. The host's slot
 // comes first, so fetches queued for one busy host hold no shared slot.
@@ -503,7 +458,7 @@ func (f *HTTPFetcher) isAllowedContentType(contentType string) bool {
 	// Extract the MIME type without parameters
 	mediaType := strings.TrimSpace(strings.Split(contentType, ";")[0])
-	for _, allowed := range allowedContentTypes() {
+	for _, allowed := range f.config.AllowedContentTypes {
 		if strings.EqualFold(mediaType, allowed) {
 			return true
 		}
@@ -513,18 +468,23 @@ func (f *HTTPFetcher) isAllowedContentType(contentType string) bool {
 }
 // validateURL checks if a URL is safe to fetch (not internal/private).
-func validateURL(ctx context.Context, fetchURL *neturl.URL, allowHTTP bool) error {
+func validateURL(ctx context.Context, rawURL string, allowHTTP bool) error {
-	if !allowHTTP && fetchURL.Scheme != "https" {
+	if !allowHTTP && !strings.HasPrefix(rawURL, "https://") {
 		return ErrUnsupportedScheme
 	}
-	// Hostname drops any port, and the brackets of an IPv6 address whether
+	// Parse to extract host
-	// or not a port follows them
+	host := extractHost(rawURL)
 	host := fetchURL.Hostname()
 	if host == "" {
 		return ErrInvalidHost
 	}
 	// Remove port if present
 	h, _, err := net.SplitHostPort(host)
 	if err == nil {
 		host = h
 	}
 	// Block obvious localhost patterns
 	if isLocalhost(host) {
 		return ErrSSRFBlocked
@@ -533,7 +493,7 @@ func validateURL(ctx context.Context, fetchURL *neturl.URL, allowHTTP bool) erro
 	// Resolve the host to check IP addresses
 	addrs, err := net.DefaultResolver.LookupIPAddr(ctx, host)
 	if err != nil {
-		return addressLookupError(host, err)
+		return fmt.Errorf("%w: %s", ErrInvalidHost, host)
 	}
 	private := slices.ContainsFunc(addrs, func(addr net.IPAddr) bool {
@@ -546,21 +506,23 @@ func validateURL(ctx context.Context, fetchURL *neturl.URL, allowHTTP bool) erro
 	return nil
 }
-// addressLookupError returns the error for a failed address lookup of host:
+// extractHost extracts the host from a URL string.
-//   - ErrUpstreamTimeout when the lookup timed out.
+func extractHost(rawURL string) string {
-//   - err, still matching context.Canceled, when the lookup was cancelled.
+	// Simple extraction without full URL parsing
-//   - ErrInvalidHost otherwise.
+	url := rawURL
-func addressLookupError(host string, err error) error {
+	if idx := strings.Index(url, "://"); idx != -1 {
-	var netErr net.Error
+		url = url[idx+3:]
 	if errors.As(err, &netErr) && netErr.Timeout() {
 		return fmt.Errorf("%w: address lookup of %s", ErrUpstreamTimeout, host)
 	}
-	if errors.Is(err, context.Canceled) {
+	if idx := strings.Index(url, "/"); idx != -1 {
-		return fmt.Errorf("address lookup cancelled: %w", err)
+		url = url[:idx]
 	}
-	return fmt.Errorf("%w: %s", ErrInvalidHost, host)
+	if idx := strings.Index(url, "?"); idx != -1 {
 		url = url[:idx]
 	}
 	return url
 }
 // isLocalhost checks if the host is localhost.
@@ -581,9 +543,6 @@ func isPrivateIP(ip net.IP) bool {
 		return true
 	}
 	// An IPv4-compatible IPv6 address is judged as the IPv4 address it holds
 	ip = ipv4CompatibleToIPv4(ip)
 	// Check for loopback
 	if ip.IsLoopback() {
 		return true
@@ -635,12 +594,7 @@ func isPrivateIP(ip net.IP) bool {
 }
 // isBlockedIP reports whether ip is refused, either by the built-in
-// internal-range check or by one of the operator-supplied prefixes. An
+// internal-range check or by one of the operator-supplied prefixes.
 // IPv4-compatible address (in ::/96) is refused when a prefix contains the
 // address as written or the IPv4 address it holds. An IPv4-mapped address (in
 // ::ffff:0:0/96) is matched only as the IPv4 address it holds: Go keeps a
 // plain IPv4 address in that form too, and an IPv6 prefix such as ::/0 must
 // not refuse every IPv4 address.
 func isBlockedIP(ip net.IP, blocked []netip.Prefix) bool {
 	if isPrivateIP(ip) {
 		return true
@@ -653,26 +607,16 @@ func isBlockedIP(ip net.IP, blocked []netip.Prefix) bool {
 	addr = addr.Unmap()
 	// ip read as IPv4 where it is or holds an IPv4 address, otherwise the
 	// zero netip.Addr, which no prefix contains. Matching asIPv4 as well as
 	// addr refuses more only for an IPv4-compatible address.
 	asIPv4, _ := netip.AddrFromSlice(ipv4CompatibleToIPv4(ip).To4())
 	return slices.ContainsFunc(blocked, func(prefix netip.Prefix) bool {
-		return prefix.Contains(addr) || prefix.Contains(asIPv4)
+		return prefix.Contains(addr)
 	})
 }
-// ipv4CompatibleToIPv4 returns the IPv4 address that an IPv4-compatible IPv6
+// ssrfSafeDialer validates IP addresses against the built-in blocked ranges
-// address (in ::/96, such as ::127.0.0.1) holds in its last four bytes, and
+// before connecting. New wraps dialSSRFSafe with the operator-supplied
-// any other address unchanged.
+// blocklist; this entry point enforces the built-in ranges alone.
-func ipv4CompatibleToIPv4(ip net.IP) net.IP {
+func ssrfSafeDialer(ctx context.Context, network, addr string) (net.Conn, error) {
-	addr, ok := netip.AddrFromSlice(ip)
+	return dialSSRFSafe(ctx, network, addr, nil)
 	if ok && netip.MustParsePrefix("::/96").Contains(addr) {
 		return ip[12:]
 	}
 	return ip
 }
 // dialSSRFSafe re-resolves addr and refuses to connect to any built-in
@@ -691,7 +635,7 @@ func dialSSRFSafe(
 	// Resolve the address
 	ips, err := net.DefaultResolver.LookupIP(ctx, "ip", host)
 	if err != nil {
-		return nil, addressLookupError(host, err)
+		return nil, fmt.Errorf("%w: %s", ErrInvalidHost, host)
 	}
 	// Check all resolved IPs
@@ -702,10 +646,7 @@ func dialSSRFSafe(
 	}
 	// Connect using the first valid IP
-	var (
+	var dialer net.Dialer
 		dialer      net.Dialer
 		lastDialErr error
 	)
 	for _, ip := range ips {
 		addr := net.JoinHostPort(ip.String(), port)
@@ -714,18 +655,9 @@ func dialSSRFSafe(
 		if err == nil {
 			return conn, nil
 		}
 		lastDialErr = err
 	}
-	// Only the last address tried decides whether the connection timed out
+	return nil, fmt.Errorf("%w to %s", errConnectFailed, host)
 	var netErr net.Error
 	if errors.As(lastDialErr, &netErr) && netErr.Timeout() {
 		return nil, fmt.Errorf("%w: connect to %s: %w",
 			ErrUpstreamTimeout, host, lastDialErr)
 	}
 	return nil, fmt.Errorf("%w to %s: %w", errConnectFailed, host, lastDialErr)
 }
 // limitedReader wraps a reader and refuses a body longer than remaining
@@ -5,34 +5,70 @@ import (
 	"errors"
 	"io"
 	"net"
 	"net/url"
 	"testing"
 	"testing/fstest"
 	"time"
 	"sneak.berlin/go/pixa/internal/imagerequest"
 )
 // testHost is the hostname used by mock fetch tests.
 const testHost = "example.com"
 func TestDefaultConfig(t *testing.T) {
 	t.Parallel()
 	cfg := DefaultConfig()
 	if cfg.Timeout != DefaultFetchTimeout {
 		t.Errorf("Timeout = %v, want %v", cfg.Timeout, DefaultFetchTimeout)
 	}
 	if cfg.MaxResponseSize != DefaultMaxResponseSize {
 		t.Errorf("MaxResponseSize = %d, want %d", cfg.MaxResponseSize, DefaultMaxResponseSize)
 	}
 	if cfg.MaxConnectionsPerHost != DefaultMaxConnectionsPerHost {
 		t.Errorf("MaxConnectionsPerHost = %d, want %d",
 			cfg.MaxConnectionsPerHost, DefaultMaxConnectionsPerHost)
 	}
 	if cfg.AllowHTTP {
 		t.Error("AllowHTTP should default to false")
 	}
 	if len(cfg.AllowedContentTypes) == 0 {
 		t.Error("AllowedContentTypes should not be empty")
 	}
 }
 func TestNewWithNilConfigUsesDefaults(t *testing.T) {
 	t.Parallel()
 	f := New(nil)
 	if f == nil {
 		t.Fatal("New(nil) returned nil")
 	}
 	if f.config == nil {
 		t.Fatal("config should be populated from DefaultConfig")
 	}
 	if f.config.Timeout != DefaultFetchTimeout {
 		t.Errorf("Timeout = %v, want %v", f.config.Timeout, DefaultFetchTimeout)
 	}
 }
 func TestIsAllowedContentType(t *testing.T) {
 	t.Parallel()
-	f := New(&Config{
+	f := New(DefaultConfig())
 		Timeout:               30 * time.Second,
 		MaxResponseSize:       50 << 20,
 		MaxConnectionsPerHost: 20,
 		MaxConnections:        64,
 	})
 	tests := []struct {
 		contentType string
 		want        bool
 	}{
-		{imagerequest.FormatJPEG.MIMEType(), true},
+		{contentTypeJPEG, true},
-		{imagerequest.FormatPNG.MIMEType(), true},
+		{contentTypePNG, true},
-		{imagerequest.FormatWebP.MIMEType(), true},
+		{contentTypeWebP, true},
 		{"image/jpeg; charset=utf-8", true},
 		{"IMAGE/JPEG", true},
 		{"text/html", false},
@@ -52,6 +88,33 @@ func TestIsAllowedContentType(t *testing.T) {
 	}
 }
 func TestExtractHost(t *testing.T) {
 	t.Parallel()
 	tests := []struct {
 		url  string
 		want string
 	}{
 		{"https://example.com/path", testHost},
 		{"http://example.com:8080/path", "example.com:8080"},
 		{"https://example.com", testHost},
 		{"https://example.com?q=1", testHost},
 		{"example.com/path", testHost},
 		{"", ""},
 	}
 	for _, tc := range tests {
 		t.Run(tc.url, func(t *testing.T) {
 			t.Parallel()
 			got := extractHost(tc.url)
 			if got != tc.want {
 				t.Errorf("extractHost(%q) = %q, want %q", tc.url, got, tc.want)
 			}
 		})
 	}
 }
 func TestIsLocalhost(t *testing.T) {
 	t.Parallel()
@@ -123,48 +186,10 @@ func TestIsPrivateIP(t *testing.T) {
 	}
 }
 // TestIsPrivateIPJudgesEmbeddedIPv4Address checks IPv6 addresses that hold an
 // IPv4 address in their last four bytes: the IPv4-compatible form (::/96) and
 // the NAT64 form (64:ff9b::/96). One holding a loopback, private or
 // link-local IPv4 address is refused as that address is, and one holding a
 // public IPv4 address in the IPv4-compatible form passes.
 func TestIsPrivateIPJudgesEmbeddedIPv4Address(t *testing.T) {
 	t.Parallel()
 	tests := []struct {
 		ip   string
 		want bool
 	}{
 		{"::127.0.0.1", true},       // loopback
 		{"::10.0.0.1", true},        // private
 		{"::169.254.169.254", true}, // link-local
 		{"64:ff9b::7f00:1", true},   // NAT64 form of 127.0.0.1
 		{"::8.8.8.8", false},        // public
 	}
 	for _, tc := range tests {
 		t.Run(tc.ip, func(t *testing.T) {
 			t.Parallel()
 			ip := net.ParseIP(tc.ip)
 			if ip == nil {
 				t.Fatalf("failed to parse IP %q", tc.ip)
 			}
 			got := isPrivateIP(ip)
 			t.Logf("isPrivateIP(%s) = %v", ip, got)
 			if got != tc.want {
 				t.Errorf("isPrivateIP(%q) = %v, want %v", tc.ip, got, tc.want)
 			}
 		})
 	}
 }
 func TestValidateURL_RejectsNonHTTPS(t *testing.T) {
 	t.Parallel()
-	err := validateURL(t.Context(), &url.URL{Scheme: "http", Host: testHost}, false)
+	err := validateURL(t.Context(), "http://example.com/path", false)
 	if !errors.Is(err, ErrUnsupportedScheme) {
 		t.Errorf("validateURL http = %v, want ErrUnsupportedScheme", err)
 	}
@@ -174,8 +199,7 @@ func TestValidateURL_AllowsHTTPWhenConfigured(t *testing.T) {
 	t.Parallel()
 	// Use a host that won't resolve (explicit .invalid TLD) so we don't hit DNS.
-	err := validateURL(t.Context(),
+	err := validateURL(t.Context(), "http://nonexistent.invalid/path", true)
 		&url.URL{Scheme: "http", Host: "nonexistent.invalid"}, true)
 	// We expect a host resolution error, not ErrUnsupportedScheme.
 	if errors.Is(err, ErrUnsupportedScheme) {
 		t.Error("validateURL with AllowHTTP should not return ErrUnsupportedScheme")
@@ -185,7 +209,7 @@ func TestValidateURL_AllowsHTTPWhenConfigured(t *testing.T) {
 func TestValidateURL_RejectsLocalhost(t *testing.T) {
 	t.Parallel()
-	err := validateURL(t.Context(), &url.URL{Scheme: "https", Host: "localhost"}, false)
+	err := validateURL(t.Context(), "https://localhost/path", false)
 	if !errors.Is(err, ErrSSRFBlocked) {
 		t.Errorf("validateURL localhost = %v, want ErrSSRFBlocked", err)
 	}
@@ -194,7 +218,7 @@ func TestValidateURL_RejectsLocalhost(t *testing.T) {
 func TestValidateURL_EmptyHost(t *testing.T) {
 	t.Parallel()
-	err := validateURL(t.Context(), &url.URL{Scheme: "https"}, false)
+	err := validateURL(t.Context(), "https:///path", false)
 	if !errors.Is(err, ErrInvalidHost) {
 		t.Errorf("validateURL empty host = %v, want ErrInvalidHost", err)
 	}
@@ -209,15 +233,14 @@ func TestMockFetcher_FetchesFile(t *testing.T) {
 	m := NewMock(mockFS)
-	result, err := m.Fetch(context.Background(),
+	result, err := m.Fetch(context.Background(), "https://example.com/images/photo.jpg")
 		imagerequest.Source{Host: testHost, Path: "/images/photo.jpg"}, "", "")
 	if err != nil {
 		t.Fatalf("Fetch() error = %v", err)
 	}
 	defer func() { _ = result.Content.Close() }()
-	if result.ContentType != imagerequest.FormatJPEG.MIMEType() {
+	if result.ContentType != contentTypeJPEG {
 		t.Errorf("ContentType = %q, want image/jpeg", result.ContentType)
 	}
@@ -241,8 +264,7 @@ func TestMockFetcher_MissingFileReturnsUpstreamError(t *testing.T) {
 	mockFS := fstest.MapFS{}
 	m := NewMock(mockFS)
-	_, err := m.Fetch(context.Background(),
+	_, err := m.Fetch(context.Background(), "https://example.com/missing.jpg")
 		imagerequest.Source{Host: testHost, Path: "/missing.jpg"}, "", "")
 	if !errors.Is(err, ErrUpstreamError) {
 		t.Errorf("Fetch() error = %v, want ErrUpstreamError", err)
 	}
@@ -259,7 +281,7 @@ func TestMockFetcher_RespectsContextCancellation(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	cancel()
-	_, err := m.Fetch(ctx, imagerequest.Source{Host: testHost, Path: "/photo.jpg"}, "", "")
+	_, err := m.Fetch(ctx, "https://example.com/photo.jpg")
 	if !errors.Is(err, context.Canceled) {
 		t.Errorf("Fetch() error = %v, want context.Canceled", err)
 	}
@@ -272,14 +294,14 @@ func TestDetectContentTypeFromPath(t *testing.T) {
 		path string
 		want string
 	}{
-		{"foo/bar.jpg", imagerequest.FormatJPEG.MIMEType()},
+		{"foo/bar.jpg", contentTypeJPEG},
-		{"foo/bar.JPG", imagerequest.FormatJPEG.MIMEType()},
+		{"foo/bar.JPG", contentTypeJPEG},
-		{"foo/bar.jpeg", imagerequest.FormatJPEG.MIMEType()},
+		{"foo/bar.jpeg", contentTypeJPEG},
-		{"foo/bar.png", imagerequest.FormatPNG.MIMEType()},
+		{"foo/bar.png", contentTypePNG},
-		{"foo/bar.gif", imagerequest.FormatGIF.MIMEType()},
+		{"foo/bar.gif", contentTypeGIF},
-		{"foo/bar.webp", imagerequest.FormatWebP.MIMEType()},
+		{"foo/bar.webp", contentTypeWebP},
-		{"foo/bar.avif", imagerequest.FormatAVIF.MIMEType()},
+		{"foo/bar.avif", contentTypeAVIF},
-		{"foo/bar.svg", imagerequest.FormatSVG.MIMEType()},
+		{"foo/bar.svg", contentTypeSVG},
 		{"foo/bar.bin", contentTypeOctetStream},
 		{"foo/bar", contentTypeOctetStream},
 	}
@@ -1,26 +1,16 @@
 package httpfetcher
-import (
+import "testing"
 	"testing"
 	"time"
 )
 // TestJPEGXLContentType verifies that the fetcher accepts an upstream answer
-// of type image/jxl, and that the mock fetcher serves a .jxl file as
+// of type image/jxl by default, and that the mock fetcher serves a .jxl file
-// image/jxl.
+// as image/jxl.
 func TestJPEGXLContentType(t *testing.T) {
 	t.Parallel()
 	const jxlType = "image/jxl"
-	f := New(&Config{
+	if !New(DefaultConfig()).isAllowedContentType(jxlType) {
 		Timeout:               30 * time.Second,
 		MaxResponseSize:       50 << 20,
 		MaxConnectionsPerHost: 20,
 		MaxConnections:        64,
 	})
 	if !f.isAllowedContentType(jxlType) {
 		t.Errorf("isAllowedContentType(%q) = false, want true", jxlType)
 	}
@@ -8,20 +8,22 @@ import (
 	"sync"
 	"testing"
 	"time"
 	"sneak.berlin/go/pixa/internal/imagerequest"
 )
-// imageSourceOn is the fake upstream's image route on host.
+// imageURLOnPort is the fake upstream's image route on testPublicHost at
 func imageSourceOn(host string) imagerequest.Source {
 	return imagerequest.Source{Host: host, Path: "/image"}
 }
 // imageSourceOnPort is the fake upstream's image route on testPublicHost at
 // port. Each port is a different host to the per-host limit, while the test
 // dialer sends every port to the one test server.
-func imageSourceOnPort(port int) imagerequest.Source {
+func imageURLOnPort(port int) string {
-	return imageSourceOn(net.JoinHostPort(testPublicHost, strconv.Itoa(port)))
+	return "http://" + net.JoinHostPort(testPublicHost, strconv.Itoa(port)) +
 		"/image"
 }
 func TestDefaultConfigMaxConnections(t *testing.T) {
 	t.Parallel()
 	if got := DefaultConfig().MaxConnections; got != DefaultMaxConnections {
 		t.Errorf("MaxConnections = %d, want %d", got, DefaultMaxConnections)
 	}
 }
 // TestFetchLimitsConnectionsToAllHostsTogether checks that MaxConnections
@@ -35,22 +37,18 @@ func TestFetchLimitsConnectionsToAllHostsTogether(t *testing.T) {
 	srv := startUpstream(t)
-	cfg := &Config{
+	cfg := DefaultConfig()
-		Timeout:               30 * time.Second,
+	cfg.MaxConnections = 2
 		MaxResponseSize:       50 << 20,
 		MaxConnectionsPerHost: 20,
 		MaxConnections:        2,
 	}
 	f, _ := newServerFetcher(t, srv, cfg)
 	f.connectionWaitTimeout = 100 * time.Millisecond
-	first, err := f.Fetch(testContext(t), imageSourceOnPort(81), "", "")
+	first, err := f.Fetch(testContext(t), imageURLOnPort(81))
 	if err != nil {
 		t.Fatalf("first Fetch() error = %v", err)
 	}
-	second, err := f.Fetch(testContext(t), imageSourceOnPort(82), "", "")
+	second, err := f.Fetch(testContext(t), imageURLOnPort(82))
 	if err != nil {
 		t.Fatalf("second Fetch() error = %v", err)
 	}
@@ -59,7 +57,7 @@ func TestFetchLimitsConnectionsToAllHostsTogether(t *testing.T) {
 	start := time.Now()
-	_, err = f.Fetch(testContext(t), imageSourceOnPort(83), "", "")
+	_, err = f.Fetch(testContext(t), imageURLOnPort(83))
 	if !errors.Is(err, ErrTooManyConnections) {
 		t.Fatalf("third Fetch() error = %v, want ErrTooManyConnections", err)
 	}
@@ -78,7 +76,7 @@ func TestFetchLimitsConnectionsToAllHostsTogether(t *testing.T) {
 		t.Fatalf("close first body: %v", err)
 	}
-	third, err := f.Fetch(testContext(t), imageSourceOnPort(83), "", "")
+	third, err := f.Fetch(testContext(t), imageURLOnPort(83))
 	if err != nil {
 		t.Fatalf("Fetch() after a response was closed: error = %v", err)
 	}
@@ -96,16 +94,12 @@ func TestFetchFreesHostSlotWhenContextEndsWaitingForConnection(t *testing.T) {
 	srv := startUpstream(t)
-	cfg := &Config{
+	cfg := DefaultConfig()
-		Timeout:               30 * time.Second,
+	cfg.MaxConnections = 1
 		MaxResponseSize:       50 << 20,
 		MaxConnectionsPerHost: 20,
 		MaxConnections:        1,
 	}
 	f, _ := newServerFetcher(t, srv, cfg)
-	first, err := f.Fetch(testContext(t), imageSourceOnPort(81), "", "")
+	first, err := f.Fetch(testContext(t), imageURLOnPort(81))
 	if err != nil {
 		t.Fatalf("first Fetch() error = %v", err)
 	}
@@ -115,7 +109,7 @@ func TestFetchFreesHostSlotWhenContextEndsWaitingForConnection(t *testing.T) {
 	ctx, cancel := context.WithTimeout(t.Context(), 100*time.Millisecond)
 	defer cancel()
-	_, err = f.Fetch(ctx, imageSourceOnPort(82), "", "")
+	_, err = f.Fetch(ctx, imageURLOnPort(82))
 	if !errors.Is(err, context.DeadlineExceeded) {
 		t.Fatalf("second Fetch() error = %v, want context.DeadlineExceeded", err)
 	}
@@ -140,7 +134,7 @@ func TestFetchRemovesIdleHostSemaphores(t *testing.T) {
 	for i := range 100 {
 		wg.Go(func() {
-			res, err := f.Fetch(ctx, imageSourceOnPort(1+i%50), "", "")
+			res, err := f.Fetch(ctx, imageURLOnPort(1+i%50))
 			if err != nil {
 				t.Errorf("Fetch() error = %v", err)
@@ -169,22 +163,19 @@ func TestFetchRemovesHostSemaphoreWhenNoConnection(t *testing.T) {
 	srv := startUpstream(t)
-	cfg := &Config{
+	cfg := DefaultConfig()
-		Timeout:               30 * time.Second,
+	cfg.MaxConnections = 1
-		MaxResponseSize:       50 << 20,
+	cfg.MaxConnectionsPerHost = 1
 		MaxConnectionsPerHost: 1,
 		MaxConnections:        1,
 	}
 	f, _ := newServerFetcher(t, srv, cfg)
 	f.connectionWaitTimeout = 100 * time.Millisecond
-	open, err := f.Fetch(testContext(t), imageSourceOnPort(81), "", "")
+	open, err := f.Fetch(testContext(t), imageURLOnPort(81))
 	if err != nil {
 		t.Fatalf("first Fetch() error = %v", err)
 	}
-	_, err = f.Fetch(testContext(t), imageSourceOnPort(82), "", "")
+	_, err = f.Fetch(testContext(t), imageURLOnPort(82))
 	if !errors.Is(err, ErrTooManyConnections) {
 		t.Fatalf("Fetch() from another host: error = %v, "+
 			"want ErrTooManyConnections", err)
@@ -193,7 +184,7 @@ func TestFetchRemovesHostSemaphoreWhenNoConnection(t *testing.T) {
 	ctx, cancel := context.WithTimeout(t.Context(), 100*time.Millisecond)
 	defer cancel()
-	_, err = f.Fetch(ctx, imageSourceOnPort(81), "", "")
+	_, err = f.Fetch(ctx, imageURLOnPort(81))
 	if !errors.Is(err, context.DeadlineExceeded) {
 		t.Fatalf("Fetch() from the busy host: error = %v, "+
 			"want context.DeadlineExceeded", err)
@@ -205,7 +196,7 @@ func TestFetchRemovesHostSemaphoreWhenNoConnection(t *testing.T) {
 	ctx, cancel = context.WithTimeout(t.Context(), 100*time.Millisecond)
 	defer cancel()
-	_, err = f.Fetch(ctx, imageSourceOnPort(83), "", "")
+	_, err = f.Fetch(ctx, imageURLOnPort(83))
 	if !errors.Is(err, context.DeadlineExceeded) {
 		t.Fatalf("Fetch() from a host with nothing open: error = %v, "+
 			"want context.DeadlineExceeded", err)
@@ -229,14 +220,14 @@ func TestFetchReleasesConnectionOnError(t *testing.T) {
 	cases := []struct {
 		name string
-		source imagerequest.Source
+		url  string
 		want error
 	}{
-		{"upstream answers 500", upstreamSource("/status/500"), ErrUpstreamError},
+		{"upstream answers 500", upstreamURL("/status/500"), ErrUpstreamError},
-		{"upstream sends HTML", upstreamSource("/html"), ErrInvalidContentType},
+		{"upstream sends HTML", upstreamURL("/html"), ErrInvalidContentType},
 		// 198.51.100.7 (TEST-NET-2) passes the SSRF checks, and the test
 		// dialer refuses every host but testPublicHost.
-		{"connecting fails", imageSourceOn("198.51.100.7"), errUnexpectedDial},
+		{"connecting fails", "http://198.51.100.7/image", errUnexpectedDial},
 	}
 	for _, tc := range cases {
@@ -245,17 +236,13 @@ func TestFetchReleasesConnectionOnError(t *testing.T) {
 			srv := startUpstream(t)
-			cfg := &Config{
+			cfg := DefaultConfig()
-				Timeout:               30 * time.Second,
+			cfg.MaxConnections = 1
 				MaxResponseSize:       50 << 20,
 				MaxConnectionsPerHost: 20,
 				MaxConnections:        1,
 			}
 			f, _ := newServerFetcher(t, srv, cfg)
 			f.connectionWaitTimeout = 100 * time.Millisecond
-			_, err := f.Fetch(testContext(t), tc.source, "", "")
+			_, err := f.Fetch(testContext(t), tc.url)
 			if !errors.Is(err, tc.want) {
 				t.Fatalf("Fetch() error = %v, want %v", err, tc.want)
 			}
@@ -7,14 +7,14 @@ import (
 	"io/fs"
 	"net/http"
 	"strings"
 	"sneak.berlin/go/pixa/internal/imagerequest"
 )
 // errEmptyURLPath is returned when a mock URL has no usable path.
 var errEmptyURLPath = errors.New("empty URL path")
 // MockFetcher implements Fetcher using an embedded filesystem.
 // Files are organized as: hostname/path/to/file.ext
-// The source with host example.com and path /images/photo.jpg maps to
+// URLs like https://example.com/images/photo.jpg map to example.com/images/photo.jpg.
 // example.com/images/photo.jpg; the source query is ignored.
 type MockFetcher struct {
 	fs fs.FS
 }
@@ -24,11 +24,8 @@ func NewMock(fsys fs.FS) *MockFetcher {
 	return &MockFetcher{fs: fsys}
 }
-// Fetch retrieves the source's content from the mock filesystem. It ignores
+// Fetch retrieves content from the mock filesystem.
-// ifNoneMatch and ifModifiedSince, and always sends the content.
+func (m *MockFetcher) Fetch(ctx context.Context, url string) (*FetchResult, error) {
 func (m *MockFetcher) Fetch(
 	ctx context.Context, source imagerequest.Source, _, _ string,
 ) (*FetchResult, error) {
 	// Check context cancellation
 	select {
 	case <-ctx.Done():
@@ -36,7 +33,11 @@ func (m *MockFetcher) Fetch(
 	default:
 	}
-	path := source.Host + source.Path
+	// Parse URL to get filesystem path
 	path, err := urlToFSPath(url)
 	if err != nil {
 		return nil, err
 	}
 	// Open the file
 	f, err := m.fs.Open(path)
@@ -67,9 +68,31 @@ func (m *MockFetcher) Fetch(
 	}, nil
 }
-// contentTypeOctetStream is the content type the mock fetcher gives files in
+// urlToFSPath converts a URL to a filesystem path.
-// no format pixa reads.
+// https://example.com/images/photo.jpg -> example.com/images/photo.jpg
-const contentTypeOctetStream = "application/octet-stream"
+func urlToFSPath(rawURL string) (string, error) {
 	// Strip scheme
 	url := rawURL
 	if idx := strings.Index(url, "://"); idx != -1 {
 		url = url[idx+3:]
 	}
 	// Remove query string
 	if idx := strings.Index(url, "?"); idx != -1 {
 		url = url[:idx]
 	}
 	// Remove fragment
 	if idx := strings.Index(url, "#"); idx != -1 {
 		url = url[:idx]
 	}
 	if url == "" {
 		return "", errEmptyURLPath
 	}
 	return url, nil
 }
 // detectContentTypeFromPath returns the MIME type based on file extension.
 func detectContentTypeFromPath(path string) string {
@@ -77,19 +100,19 @@ func detectContentTypeFromPath(path string) string {
 	switch {
 	case strings.HasSuffix(path, ".jpg"), strings.HasSuffix(path, ".jpeg"):
-		return imagerequest.FormatJPEG.MIMEType()
+		return contentTypeJPEG
 	case strings.HasSuffix(path, ".png"):
-		return imagerequest.FormatPNG.MIMEType()
+		return contentTypePNG
 	case strings.HasSuffix(path, ".gif"):
-		return imagerequest.FormatGIF.MIMEType()
+		return contentTypeGIF
 	case strings.HasSuffix(path, ".webp"):
-		return imagerequest.FormatWebP.MIMEType()
+		return contentTypeWebP
 	case strings.HasSuffix(path, ".avif"):
-		return imagerequest.FormatAVIF.MIMEType()
+		return contentTypeAVIF
 	case strings.HasSuffix(path, ".jxl"):
-		return imagerequest.FormatJXL.MIMEType()
+		return contentTypeJXL
 	case strings.HasSuffix(path, ".svg"):
-		return imagerequest.FormatSVG.MIMEType()
+		return contentTypeSVG
 	default:
 		return contentTypeOctetStream
 	}
@@ -1,213 +0,0 @@
 package httpfetcher
 import (
 	"context"
 	"errors"
 	"net"
 	"os"
 	"syscall"
 	"testing"
 	"time"
 )
 // TestFetchFailedBeforeAnswer checks the error of a fetch whose connection
 // fails:
 //   - refused: ErrUpstreamRequestFailed.
 //   - timed out: ErrUpstreamTimeout, still matching the dial's error, even for
 //     a timeout error that does not match context.DeadlineExceeded, such as
 //     the TLS handshake timeout.
 //   - cancelled by its caller: context.Canceled, not ErrUpstreamRequestFailed.
 func TestFetchFailedBeforeAnswer(t *testing.T) {
 	t.Parallel()
 	tests := []struct {
 		name       string
 		dial       func(cancel context.CancelFunc) error
 		wantErrs   []error
 		wantNotErr error
 	}{
 		{
 			name: "connection refused",
 			dial: func(context.CancelFunc) error {
 				return syscall.ECONNREFUSED
 			},
 			wantErrs:   []error{ErrUpstreamRequestFailed},
 			wantNotErr: context.Canceled,
 		},
 		{
 			name: "timed out while connecting",
 			dial: func(context.CancelFunc) error {
 				return os.ErrDeadlineExceeded
 			},
 			wantErrs:   []error{ErrUpstreamTimeout, os.ErrDeadlineExceeded},
 			wantNotErr: ErrUpstreamRequestFailed,
 		},
 		{
 			name: "cancelled while connecting",
 			dial: func(cancel context.CancelFunc) error {
 				cancel()
 				return context.Canceled
 			},
 			wantErrs:   []error{context.Canceled},
 			wantNotErr: ErrUpstreamRequestFailed,
 		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			ctx, cancel := context.WithCancel(testContext(t))
 			defer cancel()
 			f := New(&Config{
 				Timeout:               30 * time.Second,
 				MaxResponseSize:       50 << 20,
 				AllowHTTP:             true,
 				MaxConnectionsPerHost: 20,
 				MaxConnections:        64,
 				DialContext: func(context.Context, string, string) (net.Conn, error) {
 					return nil, tt.dial(cancel)
 				},
 			})
 			_, err := f.Fetch(ctx, upstreamSource("/image"), "", "")
 			t.Logf("Fetch() error: %v", err)
 			for _, wantErr := range tt.wantErrs {
 				if !errors.Is(err, wantErr) {
 					t.Errorf("Fetch() error = %v, want %v", err, wantErr)
 				}
 			}
 			if errors.Is(err, tt.wantNotErr) {
 				t.Errorf("Fetch() error = %v, must not be %v", err, tt.wantNotErr)
 			}
 		})
 	}
 }
 // TestFetchAddressLookupTimedOut checks that a fetch whose address lookup
 // times out fails with ErrUpstreamTimeout, both for the lookup of the source
 // host and for the lookup while connecting. The error must match neither
 // ErrInvalidHost nor ErrUpstreamRequestFailed, which the image routes answer
 // 502. A context whose deadline has passed makes the lookup time out.
 func TestFetchAddressLookupTimedOut(t *testing.T) {
 	t.Parallel()
 	checkTimedOut := func(t *testing.T, err error) {
 		t.Helper()
 		t.Logf("Fetch() error: %v", err)
 		if !errors.Is(err, ErrUpstreamTimeout) {
 			t.Errorf("Fetch() error = %v, want ErrUpstreamTimeout", err)
 		}
 		if errors.Is(err, ErrInvalidHost) || errors.Is(err, ErrUpstreamRequestFailed) {
 			t.Errorf("Fetch() error = %v, must match neither ErrInvalidHost "+
 				"nor ErrUpstreamRequestFailed", err)
 		}
 	}
 	t.Run("lookup of the source host", func(t *testing.T) {
 		t.Parallel()
 		ctx, cancel := context.WithTimeout(testContext(t), 0)
 		defer cancel()
 		f := New(&Config{
 			Timeout:               30 * time.Second,
 			MaxResponseSize:       50 << 20,
 			MaxConnectionsPerHost: 20,
 			MaxConnections:        64,
 		})
 		_, err := f.Fetch(ctx, imageSourceOn("cdn.example.com"), "", "")
 		checkTimedOut(t, err)
 	})
 	t.Run("lookup while connecting", func(t *testing.T) {
 		t.Parallel()
 		// The source host is an address, which validateURL does not look up;
 		// the dialer looks up a name
 		f := New(&Config{
 			Timeout:               30 * time.Second,
 			MaxResponseSize:       50 << 20,
 			MaxConnectionsPerHost: 20,
 			MaxConnections:        64,
 			DialContext: func(ctx context.Context, network, _ string) (net.Conn, error) {
 				ctx, cancel := context.WithTimeout(ctx, 0)
 				defer cancel()
 				return dialSSRFSafe(ctx, network, "img.example.com:443", nil)
 			},
 		})
 		_, err := f.Fetch(testContext(t), upstreamSource("/image"), "", "")
 		checkTimedOut(t, err)
 	})
 }
 // TestFetchConnectionTimedOut checks that a fetch whose connection in
 // dialSSRFSafe times out fails with ErrUpstreamTimeout, which the image
 // routes answer 504. The error must match neither ErrUpstreamRequestFailed
 // nor ErrInvalidHost, which they answer 502. A context whose deadline has
 // passed makes the connection time out without touching the network.
 func TestFetchConnectionTimedOut(t *testing.T) {
 	t.Parallel()
 	f := New(&Config{
 		Timeout:               30 * time.Second,
 		MaxResponseSize:       50 << 20,
 		MaxConnectionsPerHost: 20,
 		MaxConnections:        64,
 		DialContext: func(ctx context.Context, network, addr string) (net.Conn, error) {
 			ctx, cancel := context.WithTimeout(ctx, 0)
 			defer cancel()
 			return dialSSRFSafe(ctx, network, addr, nil)
 		},
 	})
 	_, err := f.Fetch(testContext(t), upstreamSource("/image"), "", "")
 	t.Logf("Fetch() error: %v", err)
 	if !errors.Is(err, ErrUpstreamTimeout) {
 		t.Errorf("Fetch() error = %v, want ErrUpstreamTimeout", err)
 	}
 	if errors.Is(err, ErrUpstreamRequestFailed) || errors.Is(err, ErrInvalidHost) {
 		t.Errorf("Fetch() error = %v, must match neither "+
 			"ErrUpstreamRequestFailed nor ErrInvalidHost", err)
 	}
 }
 // TestFetchAddressLookupCancelled checks that a fetch whose address lookup
 // its caller cancelled fails with an error matching context.Canceled, not
 // ErrInvalidHost, which the image routes answer 502.
 func TestFetchAddressLookupCancelled(t *testing.T) {
 	t.Parallel()
 	ctx, cancel := context.WithCancel(testContext(t))
 	cancel()
 	f := New(&Config{
 		Timeout:               30 * time.Second,
 		MaxResponseSize:       50 << 20,
 		MaxConnectionsPerHost: 20,
 		MaxConnections:        64,
 	})
 	_, err := f.Fetch(ctx, imageSourceOn("cdn.example.com"), "", "")
 	t.Logf("Fetch() error: %v", err)
 	if !errors.Is(err, context.Canceled) {
 		t.Errorf("Fetch() error = %v, want context.Canceled", err)
 	}
 	if errors.Is(err, ErrInvalidHost) {
 		t.Errorf("Fetch() error = %v, must not be ErrInvalidHost", err)
 	}
 }
@@ -8,7 +8,6 @@ import (
 	"testing"
 	"github.com/go-chi/chi/v5/middleware"
 	"sneak.berlin/go/pixa/internal/imagerequest"
 )
 // TestFetchSendsRequestID verifies that a fetch sends the ID of the request
@@ -26,7 +25,7 @@ func TestFetchSendsRequestID(t *testing.T) {
 		func(w http.ResponseWriter, r *http.Request) {
 			received <- r.Header.Get("X-Request-Id")
-			w.Header().Set("Content-Type", imagerequest.FormatJPEG.MIMEType())
+			w.Header().Set("Content-Type", contentTypeJPEG)
 			_, _ = io.WriteString(w, imagePayload)
 		}))
 	t.Cleanup(srv.Close)
@@ -35,7 +34,7 @@ func TestFetchSendsRequestID(t *testing.T) {
 	ctx := context.WithValue(testContext(t), middleware.RequestIDKey, requestID)
-	res, err := f.Fetch(ctx, upstreamSource("/image"), "", "")
+	res, err := f.Fetch(ctx, upstreamURL("/image"))
 	if err != nil {
 		t.Fatalf("Fetch() error = %v", err)
 	}
@@ -1,98 +0,0 @@
 package imageprocessor
 import (
 	"bytes"
 	"encoding/binary"
 	"errors"
 	"os"
 	"testing"
 	"sneak.berlin/go/pixa/internal/imagerequest"
 )
 // TestImageProcessor_RefusesAVIFAboveMaxPixels verifies that an AVIF output
 // of more than MaxAVIFOutputPixels is refused with ErrAVIFOutputTooLarge
 // before anything is decoded, whatever size and fit give it, the source's own
 // size included, and that an AVIF output of at most that many pixels, or one
 // in another format, is not. One input is a 64x32 PNG cut off in its pixel
 // data. The other is testdata/red.avif, a 4x4 AVIF, with the size in its
 // header changed to 4097x4096. libvips reads each input's size from its
 // header but fails when it decodes its pixel data, so a request that gets
 // that failure was not refused, and a refusal came before any decoding.
 func TestImageProcessor_RefusesAVIFAboveMaxPixels(t *testing.T) {
 	t.Parallel()
 	whole := createTestPNG(t, 64, 32)
 	cutOff := whole[:len(whole)/2]
 	largeAVIF, err := os.ReadFile("testdata/red.avif")
 	if err != nil {
 		t.Fatalf("failed to read test AVIF: %v", err)
 	}
 	// The ispe box gives the width and then the height, 4 bytes each, after
 	// the box's type and its 4 bytes of version and flags
 	ispe := bytes.Index(largeAVIF, []byte("ispe"))
 	binary.BigEndian.PutUint32(largeAVIF[ispe+8:], 4097)
 	binary.BigEndian.PutUint32(largeAVIF[ispe+12:], 4096)
 	tests := []struct {
 		name          string
 		input         []byte
 		sourceFormat  imagerequest.Format
 		format        imagerequest.Format
 		width, height int
 		fit           imagerequest.Fit
 		refused       bool
 	}{
 		{"AVIF at the limit", cutOff, imagerequest.FormatPNG,
 			imagerequest.FormatAVIF, 4096, 4096, imagerequest.FitCover, false},
 		{"AVIF above the limit", cutOff, imagerequest.FormatPNG,
 			imagerequest.FormatAVIF, 4096, 4097, imagerequest.FitCover, true},
 		{"WebP above the AVIF limit", cutOff, imagerequest.FormatPNG,
 			imagerequest.FormatWebP, 4096, 4097, imagerequest.FitCover, false},
 		// FitInside does not enlarge, so the output stays 64x32
 		{"AVIF inside a larger size", cutOff, imagerequest.FormatPNG,
 			imagerequest.FormatAVIF, 8192, 8192, imagerequest.FitInside, false},
 		// FitOutside scales 64x32 by 128 to cover 8192x1: 8192x4096
 		{"AVIF outside a smaller size", cutOff, imagerequest.FormatPNG,
 			imagerequest.FormatAVIF, 8192, 1, imagerequest.FitOutside, true},
 		// With no size, the output keeps the source's 4097x4096
 		{"AVIF of the source's size", largeAVIF, imagerequest.FormatAVIF,
 			imagerequest.FormatAVIF, 0, 0, imagerequest.FitCover, true},
 		{"orig of an AVIF source", largeAVIF, imagerequest.FormatAVIF,
 			imagerequest.FormatOriginal, 0, 0, imagerequest.FitCover, true},
 		{"JPEG of the source's size", largeAVIF, imagerequest.FormatAVIF,
 			imagerequest.FormatJPEG, 0, 0, imagerequest.FitCover, false},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			_, err := New(Params{
 				MaxInputBytes:           50 << 20,
 				MaxConcurrentProcessing: 1,
 			}).Process(t.Context(), bytes.NewReader(tt.input), tt.sourceFormat,
 				&imagerequest.Transform{
 					Size:    imagerequest.Size{Width: tt.width, Height: tt.height},
 					Format:  tt.format,
 					FitMode: tt.fit,
 				})
 			t.Logf("Process() error = %v", err)
 			if tt.refused {
 				if !errors.Is(err, ErrAVIFOutputTooLarge) {
 					t.Errorf("Process() error = %v, want %v", err, ErrAVIFOutputTooLarge)
 				}
 				return
 			}
 			if err == nil || errors.Is(err, ErrAVIFOutputTooLarge) {
 				t.Errorf("Process() error = %v, want the failure to decode "+
 					"the input", err)
 			}
 		})
 	}
 }
@@ -4,8 +4,6 @@ import (
 	"bytes"
 	"errors"
 	"testing"
 	"sneak.berlin/go/pixa/internal/imagerequest"
 )
 // TestImageProcessor_RefusesComputedSideAboveMaximum verifies that a size
@@ -19,17 +17,13 @@ func TestImageProcessor_RefusesComputedSideAboveMaximum(t *testing.T) {
 	tests := []struct {
 		name                    string
 		inputWidth, inputHeight int
-		size                    imagerequest.Size
+		size                    Size
 		wantErr                 error
 	}{
-		{"width at the maximum", 4096, 1,
+		{"width at the maximum", 4096, 1, Size{Height: 2}, nil},
-			imagerequest.Size{Height: 2}, nil},
+		{"width above the maximum", 4096, 1, Size{Height: 3}, ErrOutputTooLarge},
-		{"width above the maximum", 4096, 1,
+		{"height at the maximum", 1, 4096, Size{Width: 2}, nil},
-			imagerequest.Size{Height: 3}, ErrOutputTooLarge},
+		{"height above the maximum", 1, 4096, Size{Width: 3}, ErrOutputTooLarge},
 		{"height at the maximum", 1, 4096,
 			imagerequest.Size{Width: 2}, nil},
 		{"height above the maximum", 1, 4096,
 			imagerequest.Size{Width: 3}, ErrOutputTooLarge},
 	}
 	for _, tt := range tests {
@@ -38,16 +32,9 @@ func TestImageProcessor_RefusesComputedSideAboveMaximum(t *testing.T) {
 			input := createTestJPEG(t, tt.inputWidth, tt.inputHeight)
-			result, err := New(Params{
+			result, err := New(Params{}).Process(t.Context(),
-				MaxInputBytes:           50 << 20,
+				bytes.NewReader(input),
-				MaxConcurrentProcessing: 1,
+				&Request{Size: tt.size, Format: FormatJPEG, FitMode: FitCover})
 			}).Process(t.Context(),
 				bytes.NewReader(input), imagerequest.FormatJPEG,
 				&imagerequest.Transform{
 					Size:    tt.size,
 					Format:  imagerequest.FormatJPEG,
 					FitMode: imagerequest.FitCover,
 				})
 			if result != nil {
 				t.Logf("Process() made %dx%d", result.Width, result.Height)
@@ -63,79 +50,3 @@ func TestImageProcessor_RefusesComputedSideAboveMaximum(t *testing.T) {
 		})
 	}
 }
 // TestImageProcessor_ComputedSideIsAtLeastOne verifies that, for a size with
 // one side 0, the side computed from the input's proportions is 1 where it
 // would round down to 0, and that Process makes that size in every fit mode
 // but FitOutside, which scales the input to cover the size and so can make
 // it longer. Each case checks the size targetDimensions gives before it
 // calls Process: with that side at 0, an 8192x1 input at 1300x0 makes
 // libvips ask for about 39 GB with FitCover.
 func TestImageProcessor_ComputedSideIsAtLeastOne(t *testing.T) {
 	t.Parallel()
 	tests := []struct {
 		name                    string
 		inputWidth, inputHeight int
 		size                    imagerequest.Size
 		wantWidth, wantHeight   int
 	}{
 		{"8192x1 at 100x0", 8192, 1, imagerequest.Size{Width: 100}, 100, 1},
 		{"8192x1 at 1300x0", 8192, 1, imagerequest.Size{Width: 1300}, 1300, 1},
 		{"8192x2 at 100x0", 8192, 2, imagerequest.Size{Width: 100}, 100, 1},
 		{"1x8192 at 0x100", 1, 8192, imagerequest.Size{Height: 100}, 1, 100},
 		{"1x8192 at 0x1300", 1, 8192, imagerequest.Size{Height: 1300}, 1, 1300},
 		{"2x8192 at 0x100", 2, 8192, imagerequest.Size{Height: 100}, 1, 100},
 	}
 	fits := []imagerequest.Fit{
 		imagerequest.FitCover, imagerequest.FitContain, imagerequest.FitFill,
 		imagerequest.FitInside, imagerequest.FitOutside,
 	}
 	for _, tt := range tests {
 		for _, fit := range fits {
 			t.Run(tt.name+" "+string(fit), func(t *testing.T) {
 				t.Parallel()
 				width, height, err := targetDimensions(tt.size,
 					tt.inputWidth, tt.inputHeight)
 				if err != nil || width != tt.wantWidth || height != tt.wantHeight {
 					t.Fatalf("targetDimensions() = %dx%d, %v, want %dx%d",
 						width, height, err, tt.wantWidth, tt.wantHeight)
 				}
 				input := createTestJPEG(t, tt.inputWidth, tt.inputHeight)
 				result, err := New(Params{
 					MaxInputBytes:           50 << 20,
 					MaxConcurrentProcessing: 1,
 				}).Process(t.Context(),
 					bytes.NewReader(input), imagerequest.FormatJPEG,
 					&imagerequest.Transform{
 						Size:    tt.size,
 						Format:  imagerequest.FormatJPEG,
 						FitMode: fit,
 					})
 				if err != nil {
 					t.Fatalf("Process() error = %v", err)
 				}
 				defer func() { _ = result.Content.Close() }()
 				t.Logf("Process() made %dx%d", result.Width, result.Height)
 				ok := result.Width == tt.wantWidth && result.Height == tt.wantHeight
 				if fit == imagerequest.FitOutside {
 					ok = result.Width >= tt.wantWidth && result.Height >= tt.wantHeight
 				}
 				if !ok {
 					t.Errorf("Process() made %dx%d, want %dx%d (at least, for %s)",
 						result.Width, result.Height, tt.wantWidth, tt.wantHeight,
 						imagerequest.FitOutside)
 				}
 			})
 		}
 	}
 }
@@ -7,8 +7,6 @@ import (
 	"io"
 	"testing"
 	"time"
 	"sneak.berlin/go/pixa/internal/imagerequest"
 )
 // readerAfterDeadline is a Process input whose first Read waits until done
@@ -86,10 +84,9 @@ func checkProcessStopsAtDeadline(
 ) {
 	t.Helper()
-	proc := New(Params{MaxInputBytes: 50 << 20, MaxConcurrentProcessing: 1})
+	proc := New(Params{MaxConcurrentProcessing: 1})
-	result, err := proc.Process(ctx, input, imagerequest.FormatJPEG,
+	result, err := proc.Process(ctx, input, smallJPEGRequest())
 		smallJPEGTransform())
 	if result != nil {
 		t.Logf("Process() made a %dx%d image after its deadline passed",
 			result.Width, result.Height)
@@ -4,8 +4,6 @@ import (
 	"bytes"
 	"errors"
 	"testing"
 	"sneak.berlin/go/pixa/internal/imagerequest"
 )
 // TestImageProcessor_EmptyFormatRefused verifies that a request with no format
@@ -14,12 +12,8 @@ import (
 func TestImageProcessor_EmptyFormatRefused(t *testing.T) {
 	t.Parallel()
-	_, err := New(Params{
+	_, err := New(Params{}).Process(
-		MaxInputBytes:           50 << 20,
+		t.Context(), bytes.NewReader(createTestJPEG(t, 20, 20)), &Request{},
 		MaxConcurrentProcessing: 1,
 	}).Process(
 		t.Context(), bytes.NewReader(createTestJPEG(t, 20, 20)),
 		imagerequest.FormatJPEG, &imagerequest.Transform{},
 	)
 	if !errors.Is(err, ErrUnsupportedOutputFormat) {
 		t.Errorf("Process() error = %v, want %v", err, ErrUnsupportedOutputFormat)
@@ -8,21 +8,14 @@ import (
 	"testing"
 	"github.com/davidbyttow/govips/v2/vips"
 	"sneak.berlin/go/pixa/internal/imagerequest"
 )
-// processedSize runs input, an image in sourceFormat, through Process and
+// processedSize runs input through Process and returns the output's size in
-// returns the output's size in bytes.
+// bytes.
-func processedSize(
+func processedSize(t *testing.T, input []byte, req *Request) int64 {
 	t *testing.T, input []byte, sourceFormat imagerequest.Format,
 	transform *imagerequest.Transform,
 ) int64 {
 	t.Helper()
-	result, err := New(Params{
+	result, err := New(Params{}).Process(t.Context(), bytes.NewReader(input), req)
 		MaxInputBytes:           50 << 20,
 		MaxConcurrentProcessing: 1,
 	}).Process(t.Context(), bytes.NewReader(input), sourceFormat, transform)
 	if err != nil {
 		t.Fatalf("Process() error = %v", err)
 	}
@@ -75,8 +68,7 @@ func TestImageProcessor_PNGIsCompressed(t *testing.T) {
 		}
 	}
-	size := processedSize(t, encodePNG(t, flat), imagerequest.FormatPNG,
+	size := processedSize(t, encodePNG(t, flat), &Request{Format: FormatPNG})
 		&imagerequest.Transform{Format: imagerequest.FormatPNG})
 	const rawBytes = width * height * 3
 	if size > rawBytes/10 {
@@ -85,28 +77,27 @@ func TestImageProcessor_PNGIsCompressed(t *testing.T) {
 	}
 }
-// TestImageProcessor_WebPAtEffort2 verifies that WebP is saved at effort 2,
+// TestImageProcessor_WebPAtDefaultEffort verifies that WebP is saved at
-// not libvips' default of 4: the output is the size of the same image saved
+// libvips' default effort, 4: the output is the size of the same image saved
-// at effort 2.
+// at that effort.
-func TestImageProcessor_WebPAtEffort2(t *testing.T) {
+func TestImageProcessor_WebPAtDefaultEffort(t *testing.T) {
 	t.Parallel()
 	input := createTestJPEG(t, 200, 150)
-	size := processedSize(t, input, imagerequest.FormatJPEG,
+	size := processedSize(t, input, &Request{Format: FormatWebP, Quality: 85})
 		&imagerequest.Transform{Format: imagerequest.FormatWebP, Quality: 85})
 	want, _, err := decode(t, input).ExportWebp(&vips.WebpExportParams{
 		StripMetadata:   true,
 		Quality:         85,
-		ReductionEffort: 2,
+		ReductionEffort: 4,
 	})
 	if err != nil {
 		t.Fatalf("ExportWebp() error = %v", err)
 	}
 	if size != int64(len(want)) {
-		t.Errorf("WebP output is %d bytes, want %d, the size at effort 2",
+		t.Errorf("WebP output is %d bytes, want %d, the size at effort 4",
 			size, len(want))
 	}
 }
@@ -135,8 +126,7 @@ func TestImageProcessor_AVIFAtEffort1(t *testing.T) {
 	input := encodePNG(t, source)
-	size := processedSize(t, input, imagerequest.FormatPNG,
+	size := processedSize(t, input, &Request{Format: FormatAVIF, Quality: 85})
 		&imagerequest.Transform{Format: imagerequest.FormatAVIF, Quality: 85})
 	want, _, err := decode(t, input).ExportAvif(&vips.AvifExportParams{
 		StripMetadata: true,
@@ -153,30 +143,3 @@ func TestImageProcessor_AVIFAtEffort1(t *testing.T) {
 			"and 8 bits", size, len(want))
 	}
 }
 // TestImageProcessor_JPEGXLAtEffort4 verifies that JPEG XL is saved at
 // effort 4, not libvips' default of 7: the output is the size of the same
 // image saved at effort 4, with the distance exportJXL gives quality 85.
 func TestImageProcessor_JPEGXLAtEffort4(t *testing.T) {
 	t.Parallel()
 	input := createTestJPEG(t, 200, 150)
 	size := processedSize(t, input, imagerequest.FormatJPEG,
 		&imagerequest.Transform{Format: imagerequest.FormatJXL, Quality: 85})
 	params := vips.NewJxlExportParams()
 	params.Quality = 85
 	params.Distance = jxlDistance(85)
 	params.Effort = 4
 	want, _, err := decode(t, input).ExportJxl(params)
 	if err != nil {
 		t.Fatalf("ExportJxl() error = %v", err)
 	}
 	if size != int64(len(want)) {
 		t.Errorf("JPEG XL output is %d bytes, want %d, the size at effort 4",
 			size, len(want))
 	}
 }
@@ -1,287 +0,0 @@
 package imageprocessor
 import (
 	"bytes"
 	"image"
 	"image/color"
 	"image/png"
 	"math"
 	"testing"
 	"sneak.berlin/go/pixa/internal/imagerequest"
 )
 // TestImageProcessor_FitCoverServesThinSource verifies that FitCover serves
 // a thin source at the requested size. An 8192x1 source scaled to cover
 // 8192x8192 is 8192 times as long as the output on its long side. The centre
 // of an 8192x1 source with the proportions of 1x8192 is 1/8192 of a pixel
 // wide. Each case is also turned on its side.
 func TestImageProcessor_FitCoverServesThinSource(t *testing.T) {
 	t.Parallel()
 	tests := []struct {
 		name                    string
 		inputWidth, inputHeight int
 		size                    imagerequest.Size
 	}{
 		{"8192x1 at 8192x8192", 8192, 1, imagerequest.Size{Width: 8192, Height: 8192}},
 		{"8192x1 at 1x8192", 8192, 1, imagerequest.Size{Width: 1, Height: 8192}},
 		{"1x8192 at 8192x8192", 1, 8192, imagerequest.Size{Width: 8192, Height: 8192}},
 		{"1x8192 at 8192x1", 1, 8192, imagerequest.Size{Width: 8192, Height: 1}},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			input := createTestJPEG(t, tt.inputWidth, tt.inputHeight)
 			result, err := New(Params{
 				MaxInputBytes:           50 << 20,
 				MaxConcurrentProcessing: 1,
 			}).Process(t.Context(),
 				bytes.NewReader(input), imagerequest.FormatJPEG,
 				&imagerequest.Transform{
 					Size:    tt.size,
 					Format:  imagerequest.FormatJPEG,
 					FitMode: imagerequest.FitCover,
 				})
 			if err != nil {
 				t.Fatalf("Process() error = %v", err)
 			}
 			defer func() { _ = result.Content.Close() }()
 			t.Logf("Process() made %dx%d", result.Width, result.Height)
 			if result.Width != tt.size.Width || result.Height != tt.size.Height {
 				t.Errorf("Process() made %dx%d, want %dx%d",
 					result.Width, result.Height, tt.size.Width, tt.size.Height)
 			}
 		})
 	}
 }
 // createBandsPNG creates a PNG of three equal bands, red, green and blue,
 // side by side when it is wider than tall and top to bottom otherwise.
 func createBandsPNG(t *testing.T, width, height int) []byte {
 	t.Helper()
 	bands := []color.RGBA{
 		{R: 255, A: 255},
 		{G: 255, A: 255},
 		{B: 255, A: 255},
 	}
 	img := image.NewRGBA(image.Rect(0, 0, width, height))
 	for y := range height {
 		for x := range width {
 			band := 3 * y / height
 			if width > height {
 				band = 3 * x / width
 			}
 			img.Set(x, y, bands[band])
 		}
 	}
 	return encodePNG(t, img)
 }
 // TestImageProcessor_FitCoverCropsTheCentre verifies that FitCover keeps the
 // centre of the source: a 300x100 source of red, green and blue bands side
 // by side, or a 100x300 one with them top to bottom, comes out at 50x50 as
 // its green band.
 func TestImageProcessor_FitCoverCropsTheCentre(t *testing.T) {
 	t.Parallel()
 	tests := []struct {
 		name                    string
 		inputWidth, inputHeight int
 	}{
 		{"bands side by side", 300, 100},
 		{"bands top to bottom", 100, 300},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			input := createBandsPNG(t, tt.inputWidth, tt.inputHeight)
 			result, err := New(Params{
 				MaxInputBytes:           50 << 20,
 				MaxConcurrentProcessing: 1,
 			}).Process(t.Context(),
 				bytes.NewReader(input), imagerequest.FormatPNG,
 				&imagerequest.Transform{
 					Size:    imagerequest.Size{Width: 50, Height: 50},
 					Format:  imagerequest.FormatPNG,
 					FitMode: imagerequest.FitCover,
 				})
 			if err != nil {
 				t.Fatalf("Process() error = %v", err)
 			}
 			defer func() { _ = result.Content.Close() }()
 			output, err := png.Decode(result.Content)
 			if err != nil {
 				t.Fatalf("failed to decode output: %v", err)
 			}
 			bounds := output.Bounds()
 			t.Logf("Process() made %dx%d", bounds.Dx(), bounds.Dy())
 			if bounds.Dx() != 50 || bounds.Dy() != 50 {
 				t.Fatalf("Process() made %dx%d, want 50x50",
 					bounds.Dx(), bounds.Dy())
 			}
 			// Resampling may blend a little of the bands beside the
 			// green one into the output's edges.
 			for y := bounds.Min.Y; y < bounds.Max.Y; y++ {
 				for x := bounds.Min.X; x < bounds.Max.X; x++ {
 					r, g, b, _ := output.At(x, y).RGBA()
 					if r>>8 > 64 || g>>8 < 192 || b>>8 > 64 {
 						t.Fatalf("output pixel %d,%d is %d,%d,%d, want green",
 							x, y, r>>8, g>>8, b>>8)
 					}
 				}
 			}
 		})
 	}
 }
 // The greys of createSquarePNG, and the grey halfway between them.
 const (
 	backgroundGrey = 192
 	squareGrey     = 64
 	halfwayGrey    = (backgroundGrey + squareGrey) / 2
 )
 // createSquarePNG creates a grey PNG side pixels square with a darker grey
 // square squareSide pixels wide in its centre.
 func createSquarePNG(t *testing.T, side, squareSide int) []byte {
 	t.Helper()
 	first := (side - squareSide) / 2
 	last := first + squareSide - 1
 	img := image.NewGray(image.Rect(0, 0, side, side))
 	for y := range side {
 		for x := range side {
 			grey := uint8(backgroundGrey)
 			if x >= first && x <= last && y >= first && y <= last {
 				grey = squareGrey
 			}
 			img.SetGray(x, y, color.Gray{Y: grey})
 		}
 	}
 	return encodePNG(t, img)
 }
 // squareLength returns how long the square is along greys, the greys of a
 // row or column of the output that crosses it: the distance between the
 // first and the last point where greys passes halfwayGrey, or 0 when there
 // is no such point. Resampling blurs the square's edges over several
 // pixels, and each point is placed between the two pixels on either side
 // of it in proportion to their greys, so the length is measured to a
 // fraction of a pixel.
 func squareLength(greys []float64) float64 {
 	first, last := -1.0, -1.0
 	for i := 1; i < len(greys); i++ {
 		before, after := greys[i-1], greys[i]
 		if (before > halfwayGrey) == (after > halfwayGrey) {
 			continue
 		}
 		point := float64(i-1) + (before-halfwayGrey)/(before-after)
 		if first < 0 {
 			first = point
 		}
 		last = point
 	}
 	return last - first
 }
 // TestImageProcessor_FitCoverKeepsProportions verifies that FitCover scales
 // both sides of the source by the same amount: a square in the centre of
 // the source comes out square. Its width and height are measured along the
 // output's middle row and column.
 func TestImageProcessor_FitCoverKeepsProportions(t *testing.T) {
 	t.Parallel()
 	tests := []struct {
 		name             string
 		side, squareSide int
 		size             imagerequest.Size
 	}{
 		{"16x16 at 100x60", 16, 8, imagerequest.Size{Width: 100, Height: 60}},
 		{"16x16 at 60x100", 16, 8, imagerequest.Size{Width: 60, Height: 100}},
 		{"10x10 at 100x35", 10, 2, imagerequest.Size{Width: 100, Height: 35}},
 		{"10x10 at 35x100", 10, 2, imagerequest.Size{Width: 35, Height: 100}},
 		{"64x64 at 300x100", 64, 16, imagerequest.Size{Width: 300, Height: 100}},
 		{"64x64 at 100x300", 64, 16, imagerequest.Size{Width: 100, Height: 300}},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			input := createSquarePNG(t, tt.side, tt.squareSide)
 			result, err := New(Params{
 				MaxInputBytes:           50 << 20,
 				MaxConcurrentProcessing: 1,
 			}).Process(t.Context(),
 				bytes.NewReader(input), imagerequest.FormatPNG,
 				&imagerequest.Transform{
 					Size:    tt.size,
 					Format:  imagerequest.FormatPNG,
 					FitMode: imagerequest.FitCover,
 				})
 			if err != nil {
 				t.Fatalf("Process() error = %v", err)
 			}
 			defer func() { _ = result.Content.Close() }()
 			output, err := png.Decode(result.Content)
 			if err != nil {
 				t.Fatalf("failed to decode output: %v", err)
 			}
 			bounds := output.Bounds()
 			if bounds.Dx() != tt.size.Width || bounds.Dy() != tt.size.Height {
 				t.Fatalf("Process() made %dx%d, want %dx%d",
 					bounds.Dx(), bounds.Dy(), tt.size.Width, tt.size.Height)
 			}
 			row := make([]float64, bounds.Dx())
 			for x := range row {
 				r, _, _, _ := output.At(x, bounds.Dy()/2).RGBA()
 				row[x] = float64(r >> 8)
 			}
 			column := make([]float64, bounds.Dy())
 			for y := range column {
 				r, _, _, _ := output.At(bounds.Dx()/2, y).RGBA()
 				column[y] = float64(r >> 8)
 			}
 			width, height := squareLength(row), squareLength(column)
 			t.Logf("square is %.2f wide and %.2f high", width, height)
 			if width == 0 || math.Abs(width-height) > 0.5 {
 				t.Errorf("square is %.2f wide and %.2f high, want it square",
 					width, height)
 			}
 		})
 	}
 }
@@ -4,8 +4,6 @@ import (
 	"bytes"
 	"errors"
 	"testing"
 	"sneak.berlin/go/pixa/internal/imagerequest"
 )
 // TestImageProcessor_RefusesFitOutsideAboveMaximum verifies that FitOutside,
@@ -19,20 +17,15 @@ func TestImageProcessor_RefusesFitOutsideAboveMaximum(t *testing.T) {
 	tests := []struct {
 		name                    string
 		inputWidth, inputHeight int
-		size                    imagerequest.Size
+		size                    Size
 		// wantWidth and wantHeight are the output's, 0 for a refusal
 		wantWidth, wantHeight int
 	}{
-		{"width above the maximum", 3000, 600,
+		{"width above the maximum", 3000, 600, Size{Width: 1, Height: 8192}, 0, 0},
-			imagerequest.Size{Width: 1, Height: 8192}, 0, 0},
+		{"height above the maximum", 600, 3000, Size{Width: 8192, Height: 1}, 0, 0},
-		{"height above the maximum", 600, 3000,
+		{"width at the maximum", 1024, 256, Size{Width: 1, Height: 2048}, 8192, 2048},
-			imagerequest.Size{Width: 8192, Height: 1}, 0, 0},
+		{"height at the maximum", 256, 1024, Size{Width: 2048, Height: 1}, 2048, 8192},
-		{"width at the maximum", 1024, 256,
+		{"within the maximum", 3000, 600, Size{Width: 1, Height: 1200}, 6000, 1200},
 			imagerequest.Size{Width: 1, Height: 2048}, 8192, 2048},
 		{"height at the maximum", 256, 1024,
 			imagerequest.Size{Width: 2048, Height: 1}, 2048, 8192},
 		{"within the maximum", 3000, 600,
 			imagerequest.Size{Width: 1, Height: 1200}, 6000, 1200},
 	}
 	for _, tt := range tests {
@@ -41,16 +34,9 @@ func TestImageProcessor_RefusesFitOutsideAboveMaximum(t *testing.T) {
 			input := createTestJPEG(t, tt.inputWidth, tt.inputHeight)
-			result, err := New(Params{
+			result, err := New(Params{}).Process(t.Context(),
-				MaxInputBytes:           50 << 20,
+				bytes.NewReader(input),
-				MaxConcurrentProcessing: 1,
+				&Request{Size: tt.size, Format: FormatJPEG, FitMode: FitOutside})
 			}).Process(t.Context(),
 				bytes.NewReader(input), imagerequest.FormatJPEG,
 				&imagerequest.Transform{
 					Size:    tt.size,
 					Format:  imagerequest.FormatJPEG,
 					FitMode: imagerequest.FitOutside,
 				})
 			if result != nil {
 				t.Logf("Process() made %dx%d", result.Width, result.Height)
 			}
@@ -74,52 +60,3 @@ func TestImageProcessor_RefusesFitOutsideAboveMaximum(t *testing.T) {
 		})
 	}
 }
 // TestImageProcessor_FitOutsideSideIsAtLeastOne verifies that FitOutside
 // keeps each side at 1 or more when it works both sides out again from the
 // larger scale. A side of 49 scaled to 1 is 49 times 1/49, which in floating
 // point is just under 1 and so rounded down to 0, a width libvips refuses.
 func TestImageProcessor_FitOutsideSideIsAtLeastOne(t *testing.T) {
 	t.Parallel()
 	tests := []struct {
 		name                    string
 		inputWidth, inputHeight int
 		size                    imagerequest.Size
 		wantWidth, wantHeight   int
 	}{
 		{"49x8192 at 0x100", 49, 8192, imagerequest.Size{Height: 100}, 1, 167},
 		{"49x49 at 1x1", 49, 49, imagerequest.Size{Width: 1, Height: 1}, 1, 1},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			input := createTestJPEG(t, tt.inputWidth, tt.inputHeight)
 			result, err := New(Params{
 				MaxInputBytes:           50 << 20,
 				MaxConcurrentProcessing: 1,
 			}).Process(t.Context(),
 				bytes.NewReader(input), imagerequest.FormatJPEG,
 				&imagerequest.Transform{
 					Size:    tt.size,
 					Format:  imagerequest.FormatJPEG,
 					FitMode: imagerequest.FitOutside,
 				})
 			if err != nil {
 				t.Fatalf("Process() error = %v", err)
 			}
 			defer func() { _ = result.Content.Close() }()
 			t.Logf("Process() made %dx%d", result.Width, result.Height)
 			if result.Width != tt.wantWidth || result.Height != tt.wantHeight {
 				t.Errorf("Process() made %dx%d, want %dx%d",
 					result.Width, result.Height, tt.wantWidth, tt.wantHeight)
 			}
 		})
 	}
 }
@@ -15,15 +15,9 @@ import (
 	"testing"
 	"github.com/davidbyttow/govips/v2/vips"
 	"sneak.berlin/go/pixa/internal/imagerequest"
 )
 func TestMain(m *testing.M) {
 	// The SVG tests start this test binary again as SVG child processes
 	if IsSVGChildProcess(os.Args[1:]) {
 		os.Exit(RunAsSVGChildProcess(os.Args[1:]))
 	}
 	initVips()
 	code := m.Run()
@@ -93,29 +87,29 @@ func isAVIF(data []byte) bool {
 	brand := string(data[8:12])
-	return brand == string(imagerequest.FormatAVIF) || brand == "avis"
+	return brand == string(FormatAVIF) || brand == "avis"
 }
 // detectMIME is a minimal magic-byte detector for test assertions.
 func detectMIME(data []byte) string {
 	if len(data) >= 3 && data[0] == 0xFF && data[1] == 0xD8 && data[2] == 0xFF {
-		return imagerequest.FormatJPEG.MIMEType()
+		return mimeJPEG
 	}
 	if len(data) >= 8 && string(data[:8]) == "\x89PNG\r\n\x1a\n" {
-		return imagerequest.FormatPNG.MIMEType()
+		return mimePNG
 	}
 	if len(data) >= 4 && string(data[:4]) == "GIF8" {
-		return imagerequest.FormatGIF.MIMEType()
+		return mimeGIF
 	}
 	if len(data) >= 12 && string(data[:4]) == "RIFF" && string(data[8:12]) == "WEBP" {
-		return imagerequest.FormatWebP.MIMEType()
+		return mimeWebP
 	}
 	if isAVIF(data) {
-		return imagerequest.FormatAVIF.MIMEType()
+		return mimeAVIF
 	}
 	return ""
@@ -124,20 +118,19 @@ func detectMIME(data []byte) string {
 func TestImageProcessor_ResizeJPEG(t *testing.T) {
 	t.Parallel()
-	proc := New(Params{MaxInputBytes: 50 << 20, MaxConcurrentProcessing: 1})
+	proc := New(Params{})
 	ctx := context.Background()
 	input := createTestJPEG(t, 800, 600)
-	transform := &imagerequest.Transform{
+	req := &Request{
-		Size:    imagerequest.Size{Width: 400, Height: 300},
+		Size:    Size{Width: 400, Height: 300},
-		Format:  imagerequest.FormatJPEG,
+		Format:  FormatJPEG,
 		Quality: 85,
-		FitMode: imagerequest.FitCover,
+		FitMode: FitCover,
 	}
-	result, err := proc.Process(ctx, bytes.NewReader(input),
+	result, err := proc.Process(ctx, bytes.NewReader(input), req)
 		imagerequest.FormatJPEG, transform)
 	if err != nil {
 		t.Fatalf("Process() error = %v", err)
 	}
@@ -163,7 +156,7 @@ func TestImageProcessor_ResizeJPEG(t *testing.T) {
 	}
 	mime := detectMIME(data)
-	if mime != imagerequest.FormatJPEG.MIMEType() {
+	if mime != mimeJPEG {
 		t.Errorf("Output format = %v, want image/jpeg", mime)
 	}
 }
@@ -171,19 +164,18 @@ func TestImageProcessor_ResizeJPEG(t *testing.T) {
 func TestImageProcessor_ConvertToPNG(t *testing.T) {
 	t.Parallel()
-	proc := New(Params{MaxInputBytes: 50 << 20, MaxConcurrentProcessing: 1})
+	proc := New(Params{})
 	ctx := context.Background()
 	input := createTestJPEG(t, 200, 150)
-	transform := &imagerequest.Transform{
+	req := &Request{
-		Size:    imagerequest.Size{Width: 200, Height: 150},
+		Size:    Size{Width: 200, Height: 150},
-		Format:  imagerequest.FormatPNG,
+		Format:  FormatPNG,
-		FitMode: imagerequest.FitCover,
+		FitMode: FitCover,
 	}
-	result, err := proc.Process(ctx, bytes.NewReader(input),
+	result, err := proc.Process(ctx, bytes.NewReader(input), req)
 		imagerequest.FormatJPEG, transform)
 	if err != nil {
 		t.Fatalf("Process() error = %v", err)
 	}
@@ -196,7 +188,7 @@ func TestImageProcessor_ConvertToPNG(t *testing.T) {
 	}
 	mime := detectMIME(data)
-	if mime != imagerequest.FormatPNG.MIMEType() {
+	if mime != mimePNG {
 		t.Errorf("Output format = %v, want image/png", mime)
 	}
 }
@@ -204,24 +196,23 @@ func TestImageProcessor_ConvertToPNG(t *testing.T) {
 // processAndCheckSize processes a test JPEG of the given input dimensions
 // with the requested size and asserts the resulting dimensions.
 func processAndCheckSize(
-	t *testing.T, inputW, inputH int, size imagerequest.Size, wantW, wantH int,
+	t *testing.T, inputW, inputH int, size Size, wantW, wantH int,
 ) {
 	t.Helper()
-	proc := New(Params{MaxInputBytes: 50 << 20, MaxConcurrentProcessing: 1})
+	proc := New(Params{})
 	ctx := context.Background()
 	input := createTestJPEG(t, inputW, inputH)
-	transform := &imagerequest.Transform{
+	req := &Request{
 		Size:    size,
-		Format:  imagerequest.FormatJPEG,
+		Format:  FormatJPEG,
 		Quality: 85,
-		FitMode: imagerequest.FitCover,
+		FitMode: FitCover,
 	}
-	result, err := proc.Process(ctx, bytes.NewReader(input),
+	result, err := proc.Process(ctx, bytes.NewReader(input), req)
 		imagerequest.FormatJPEG, transform)
 	if err != nil {
 		t.Fatalf("Process() error = %v", err)
 	}
@@ -241,28 +232,27 @@ func TestImageProcessor_OriginalSize(t *testing.T) {
 	t.Parallel()
 	// Width and height 0: keep original size
-	processAndCheckSize(t, 640, 480, imagerequest.Size{Width: 0, Height: 0}, 640, 480)
+	processAndCheckSize(t, 640, 480, Size{Width: 0, Height: 0}, 640, 480)
 }
 func TestImageProcessor_FitContain(t *testing.T) {
 	t.Parallel()
-	proc := New(Params{MaxInputBytes: 50 << 20, MaxConcurrentProcessing: 1})
+	proc := New(Params{})
 	ctx := context.Background()
 	// 800x400 image (2:1 aspect) into 400x400 box with contain
 	// Should result in 400x200 (maintaining aspect ratio)
 	input := createTestJPEG(t, 800, 400)
-	transform := &imagerequest.Transform{
+	req := &Request{
-		Size:    imagerequest.Size{Width: 400, Height: 400},
+		Size:    Size{Width: 400, Height: 400},
-		Format:  imagerequest.FormatJPEG,
+		Format:  FormatJPEG,
 		Quality: 85,
-		FitMode: imagerequest.FitContain,
+		FitMode: FitContain,
 	}
-	result, err := proc.Process(ctx, bytes.NewReader(input),
+	result, err := proc.Process(ctx, bytes.NewReader(input), req)
 		imagerequest.FormatJPEG, transform)
 	if err != nil {
 		t.Fatalf("Process() error = %v", err)
 	}
@@ -280,7 +270,7 @@ func TestImageProcessor_ProportionalScale_WidthOnly(t *testing.T) {
 	// 800x600 image, request width=400 height=0
 	// Should scale proportionally to 400x300
-	processAndCheckSize(t, 800, 600, imagerequest.Size{Width: 400, Height: 0}, 400, 300)
+	processAndCheckSize(t, 800, 600, Size{Width: 400, Height: 0}, 400, 300)
 }
 func TestImageProcessor_ProportionalScale_HeightOnly(t *testing.T) {
@@ -288,25 +278,24 @@ func TestImageProcessor_ProportionalScale_HeightOnly(t *testing.T) {
 	// 800x600 image, request width=0 height=300
 	// Should scale proportionally to 400x300
-	processAndCheckSize(t, 800, 600, imagerequest.Size{Width: 0, Height: 300}, 400, 300)
+	processAndCheckSize(t, 800, 600, Size{Width: 0, Height: 300}, 400, 300)
 }
 func TestImageProcessor_ProcessPNG(t *testing.T) {
 	t.Parallel()
-	proc := New(Params{MaxInputBytes: 50 << 20, MaxConcurrentProcessing: 1})
+	proc := New(Params{})
 	ctx := context.Background()
 	input := createTestPNG(t, 400, 300)
-	transform := &imagerequest.Transform{
+	req := &Request{
-		Size:    imagerequest.Size{Width: 200, Height: 150},
+		Size:    Size{Width: 200, Height: 150},
-		Format:  imagerequest.FormatPNG,
+		Format:  FormatPNG,
-		FitMode: imagerequest.FitCover,
+		FitMode: FitCover,
 	}
-	result, err := proc.Process(ctx, bytes.NewReader(input),
+	result, err := proc.Process(ctx, bytes.NewReader(input), req)
 		imagerequest.FormatPNG, transform)
 	if err != nil {
 		t.Fatalf("Process() error = %v", err)
 	}
@@ -322,6 +311,22 @@ func TestImageProcessor_ProcessPNG(t *testing.T) {
 	}
 }
 func TestImageProcessor_SupportedFormats(t *testing.T) {
 	t.Parallel()
 	proc := New(Params{})
 	inputFormats := proc.SupportedInputFormats()
 	if len(inputFormats) == 0 {
 		t.Error("SupportedInputFormats() returned empty slice")
 	}
 	outputFormats := proc.SupportedOutputFormats()
 	if len(outputFormats) == 0 {
 		t.Error("SupportedOutputFormats() returned empty slice")
 	}
 }
 func TestImageProcessor_RejectsOversizedInput(t *testing.T) {
 	t.Parallel()
@@ -340,19 +345,18 @@ func TestImageProcessor_RejectsOversizedInput(t *testing.T) {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
-			proc := New(Params{MaxInputBytes: 50 << 20, MaxConcurrentProcessing: 1})
+			proc := New(Params{})
 			ctx := context.Background()
 			input := createTestJPEG(t, tt.width, tt.height)
-			transform := &imagerequest.Transform{
+			req := &Request{
-				Size:    imagerequest.Size{Width: 100, Height: 100},
+				Size:    Size{Width: 100, Height: 100},
-				Format:  imagerequest.FormatJPEG,
+				Format:  FormatJPEG,
 				Quality: 85,
-				FitMode: imagerequest.FitCover,
+				FitMode: FitCover,
 			}
-			_, err := proc.Process(ctx, bytes.NewReader(input),
+			_, err := proc.Process(ctx, bytes.NewReader(input), req)
 				imagerequest.FormatJPEG, transform)
 			if err == nil {
 				t.Error("Process() should reject oversized input images")
 			}
@@ -367,21 +371,20 @@ func TestImageProcessor_RejectsOversizedInput(t *testing.T) {
 func TestImageProcessor_AcceptsMaxDimensionInput(t *testing.T) {
 	t.Parallel()
-	proc := New(Params{MaxInputBytes: 50 << 20, MaxConcurrentProcessing: 1})
+	proc := New(Params{})
 	ctx := context.Background()
 	// Create an image at exactly MaxInputDimension - should be accepted
 	input := createTestJPEG(t, MaxInputDimension, 100)
-	transform := &imagerequest.Transform{
+	req := &Request{
-		Size:    imagerequest.Size{Width: 100, Height: 100},
+		Size:    Size{Width: 100, Height: 100},
-		Format:  imagerequest.FormatJPEG,
+		Format:  FormatJPEG,
 		Quality: 85,
-		FitMode: imagerequest.FitCover,
+		FitMode: FitCover,
 	}
-	result, err := proc.Process(ctx, bytes.NewReader(input),
+	result, err := proc.Process(ctx, bytes.NewReader(input), req)
 		imagerequest.FormatJPEG, transform)
 	if err != nil {
 		t.Fatalf(
 			"Process() should accept images at MaxInputDimension, got error: %v",
@@ -394,25 +397,22 @@ func TestImageProcessor_AcceptsMaxDimensionInput(t *testing.T) {
 // encodeAndCheck processes a 200x150 test JPEG into a 100x75 output of the
 // given format and asserts the output MIME type and dimensions.
-func encodeAndCheck(
+func encodeAndCheck(t *testing.T, format Format, quality int, wantMIME string) {
 	t *testing.T, format imagerequest.Format, quality int, wantMIME string,
 ) {
 	t.Helper()
-	proc := New(Params{MaxInputBytes: 50 << 20, MaxConcurrentProcessing: 1})
+	proc := New(Params{})
 	ctx := context.Background()
 	input := createTestJPEG(t, 200, 150)
-	transform := &imagerequest.Transform{
+	req := &Request{
-		Size:    imagerequest.Size{Width: 100, Height: 75},
+		Size:    Size{Width: 100, Height: 75},
 		Format:  format,
 		Quality: quality,
-		FitMode: imagerequest.FitCover,
+		FitMode: FitCover,
 	}
-	result, err := proc.Process(ctx, bytes.NewReader(input),
+	result, err := proc.Process(ctx, bytes.NewReader(input), req)
 		imagerequest.FormatJPEG, transform)
 	if err != nil {
 		t.Fatalf("Process() error = %v, want nil", err)
 	}
@@ -443,13 +443,13 @@ func encodeAndCheck(
 func TestImageProcessor_EncodeWebP(t *testing.T) {
 	t.Parallel()
-	encodeAndCheck(t, imagerequest.FormatWebP, 80, imagerequest.FormatWebP.MIMEType())
+	encodeAndCheck(t, FormatWebP, 80, mimeWebP)
 }
 func TestImageProcessor_DecodeAVIF(t *testing.T) {
 	t.Parallel()
-	proc := New(Params{MaxInputBytes: 50 << 20, MaxConcurrentProcessing: 1})
+	proc := New(Params{})
 	ctx := context.Background()
 	// Load test AVIF file
@@ -459,15 +459,14 @@ func TestImageProcessor_DecodeAVIF(t *testing.T) {
 	}
 	// Request resize and convert to JPEG
-	transform := &imagerequest.Transform{
+	req := &Request{
-		Size:    imagerequest.Size{Width: 2, Height: 2},
+		Size:    Size{Width: 2, Height: 2},
-		Format:  imagerequest.FormatJPEG,
+		Format:  FormatJPEG,
 		Quality: 85,
-		FitMode: imagerequest.FitCover,
+		FitMode: FitCover,
 	}
-	result, err := proc.Process(ctx, bytes.NewReader(input),
+	result, err := proc.Process(ctx, bytes.NewReader(input), req)
 		imagerequest.FormatAVIF, transform)
 	if err != nil {
 		t.Fatalf("Process() error = %v, want nil (AVIF decoding should work)", err)
 	}
@@ -481,7 +480,7 @@ func TestImageProcessor_DecodeAVIF(t *testing.T) {
 	}
 	mime := detectMIME(data)
-	if mime != imagerequest.FormatJPEG.MIMEType() {
+	if mime != mimeJPEG {
 		t.Errorf("Output format = %v, want image/jpeg", mime)
 	}
 }
@@ -492,7 +491,7 @@ func TestImageProcessor_RejectsOversizedInputData(t *testing.T) {
 	// Create a processor with a very small byte limit
 	const limit = 1024
-	proc := New(Params{MaxInputBytes: limit, MaxConcurrentProcessing: 1})
+	proc := New(Params{MaxInputBytes: limit})
 	ctx := context.Background()
 	// Create a valid JPEG that exceeds the byte limit
@@ -501,15 +500,14 @@ func TestImageProcessor_RejectsOversizedInputData(t *testing.T) {
 		t.Fatalf("test JPEG must exceed %d bytes, got %d", limit, len(input))
 	}
-	transform := &imagerequest.Transform{
+	req := &Request{
-		Size:    imagerequest.Size{Width: 100, Height: 75},
+		Size:    Size{Width: 100, Height: 75},
-		Format:  imagerequest.FormatJPEG,
+		Format:  FormatJPEG,
 		Quality: 85,
-		FitMode: imagerequest.FitCover,
+		FitMode: FitCover,
 	}
-	_, err := proc.Process(ctx, bytes.NewReader(input),
+	_, err := proc.Process(ctx, bytes.NewReader(input), req)
 		imagerequest.FormatJPEG, transform)
 	if err == nil {
 		t.Fatal("Process() should reject input exceeding maxInputBytes")
 	}
@@ -526,18 +524,17 @@ func TestImageProcessor_AcceptsInputWithinLimit(t *testing.T) {
 	input := createTestJPEG(t, 10, 10)
 	limit := int64(len(input)) * 10 // 10× headroom
-	proc := New(Params{MaxInputBytes: limit, MaxConcurrentProcessing: 1})
+	proc := New(Params{MaxInputBytes: limit})
 	ctx := context.Background()
-	transform := &imagerequest.Transform{
+	req := &Request{
-		Size:    imagerequest.Size{Width: 10, Height: 10},
+		Size:    Size{Width: 10, Height: 10},
-		Format:  imagerequest.FormatJPEG,
+		Format:  FormatJPEG,
 		Quality: 85,
-		FitMode: imagerequest.FitCover,
+		FitMode: FitCover,
 	}
-	result, err := proc.Process(ctx, bytes.NewReader(input),
+	result, err := proc.Process(ctx, bytes.NewReader(input), req)
 		imagerequest.FormatJPEG, transform)
 	if err != nil {
 		t.Fatalf("Process() error = %v, want nil", err)
 	}
@@ -545,25 +542,35 @@ func TestImageProcessor_AcceptsInputWithinLimit(t *testing.T) {
 	defer func() { _ = result.Content.Close() }()
 }
 func TestImageProcessor_DefaultMaxInputBytes(t *testing.T) {
 	t.Parallel()
 	// Passing 0 should use the default
 	proc := New(Params{})
 	if proc.maxInputBytes != DefaultMaxInputBytes {
 		t.Errorf("maxInputBytes = %d, want %d", proc.maxInputBytes, DefaultMaxInputBytes)
 	}
 	// Passing negative should also use the default
 	proc = New(Params{MaxInputBytes: -1})
 	if proc.maxInputBytes != DefaultMaxInputBytes {
 		t.Errorf("maxInputBytes = %d, want %d", proc.maxInputBytes, DefaultMaxInputBytes)
 	}
 }
 func TestImageProcessor_EncodeAVIF(t *testing.T) {
 	t.Parallel()
-	encodeAndCheck(t, imagerequest.FormatAVIF, 85, imagerequest.FormatAVIF.MIMEType())
+	encodeAndCheck(t, FormatAVIF, 85, mimeAVIF)
 }
-// processAndDecode runs input, a JPEG, through Process and decodes the output
+// processAndDecode runs input through Process and decodes the output with
-// with vips, so a test can inspect the image a client would receive.
+// vips, so a test can inspect the image a client would receive.
-func processAndDecode(
+func processAndDecode(t *testing.T, input []byte, req *Request) *vips.ImageRef {
 	t *testing.T, input []byte, transform *imagerequest.Transform,
 ) *vips.ImageRef {
 	t.Helper()
-	result, err := New(Params{
+	result, err := New(Params{}).Process(
-		MaxInputBytes:           50 << 20,
+		context.Background(), bytes.NewReader(input), req,
 		MaxConcurrentProcessing: 1,
 	}).Process(
 		context.Background(), bytes.NewReader(input), imagerequest.FormatJPEG,
 		transform,
 	)
 	if err != nil {
 		t.Fatalf("Process() error = %v", err)
@@ -607,17 +614,15 @@ func TestImageProcessor_StripsEXIF(t *testing.T) {
 		t.Fatal("testdata/gps-exif.jpg has no GPS latitude")
 	}
-	formats := []imagerequest.Format{
+	formats := []Format{
-		imagerequest.FormatJPEG, imagerequest.FormatPNG, imagerequest.FormatWebP,
+		FormatJPEG, FormatPNG, FormatWebP, FormatAVIF, FormatGIF, FormatOriginal,
 		imagerequest.FormatAVIF, imagerequest.FormatGIF, imagerequest.FormatOriginal,
 	}
 	for _, format := range formats {
 		t.Run(string(format), func(t *testing.T) {
 			t.Parallel()
-			output := processAndDecode(t, input,
+			output := processAndDecode(t, input, &Request{Format: format})
 				&imagerequest.Transform{Format: format})
 			if output.HasExif() {
 				t.Errorf("output has EXIF: %v", output.GetExif())
@@ -639,21 +644,21 @@ func TestImageProcessor_AppliesEXIFOrientation(t *testing.T) {
 	tests := []struct {
 		name  string
-		size  imagerequest.Size
+		size  Size
 		wantW int
 		wantH int
 	}{
-		{name: "original size", size: imagerequest.Size{}, wantW: 8, wantH: 16},
+		{name: "original size", size: Size{}, wantW: 8, wantH: 16},
-		{name: "width only", size: imagerequest.Size{Width: 4}, wantW: 4, wantH: 8},
+		{name: "width only", size: Size{Width: 4}, wantW: 4, wantH: 8},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
-			output := processAndDecode(t, input, &imagerequest.Transform{
+			output := processAndDecode(t, input, &Request{
 				Size:   tt.size,
-				Format: imagerequest.FormatPNG,
+				Format: FormatPNG,
 			})
 			if output.Width() != tt.wantW || output.Height() != tt.wantH {
@@ -689,8 +694,7 @@ func TestImageProcessor_ConvertsWideGamutToSRGB(t *testing.T) {
 		t.Fatalf("failed to read test JPEG: %v", err)
 	}
-	output := processAndDecode(t, input,
+	output := processAndDecode(t, input, &Request{Format: FormatPNG})
 		&imagerequest.Transform{Format: imagerequest.FormatPNG})
 	if output.HasICCProfile() {
 		t.Error("output has an ICC profile")
@@ -8,7 +8,6 @@ import (
 	"testing"
 	"github.com/davidbyttow/govips/v2/vips"
 	"sneak.berlin/go/pixa/internal/imagerequest"
 )
 // TestImageProcessor_EncodeJPEGXL converts a JPEG to a smaller JPEG XL and
@@ -16,17 +15,10 @@ import (
 func TestImageProcessor_EncodeJPEGXL(t *testing.T) {
 	t.Parallel()
-	transform := &imagerequest.Transform{
+	req := &Request{Size: Size{Width: 100, Height: 75}, Format: FormatJXL}
 		Size:   imagerequest.Size{Width: 100, Height: 75},
 		Format: imagerequest.FormatJXL,
 	}
-	result, err := New(Params{
+	result, err := New(Params{}).Process(
-		MaxInputBytes:           50 << 20,
+		t.Context(), bytes.NewReader(createTestJPEG(t, 200, 150)), req,
 		MaxConcurrentProcessing: 1,
 	}).Process(
 		t.Context(), bytes.NewReader(createTestJPEG(t, 200, 150)),
 		imagerequest.FormatJPEG, transform,
 	)
 	if err != nil {
 		t.Fatalf("Process() error = %v", err)
@@ -68,12 +60,8 @@ func TestImageProcessor_JPEGXLQuality(t *testing.T) {
 	outputBytes := make(map[int]int64)
 	for _, quality := range []int{30, 90} {
-		result, err := New(Params{
+		result, err := New(Params{}).Process(t.Context(),
-			MaxInputBytes:           50 << 20,
+			bytes.NewReader(input), &Request{Format: FormatJXL, Quality: quality})
 			MaxConcurrentProcessing: 1,
 		}).Process(t.Context(),
 			bytes.NewReader(input), imagerequest.FormatJPEG,
 			&imagerequest.Transform{Format: imagerequest.FormatJXL, Quality: quality})
 		if err != nil {
 			t.Fatalf("Process() at quality %d error = %v", quality, err)
 		}
@@ -101,8 +89,7 @@ func TestImageProcessor_JPEGXLDropsSourceEXIF(t *testing.T) {
 		t.Fatalf("failed to read test JPEG: %v", err)
 	}
-	exif := processAndDecode(t, input,
+	exif := processAndDecode(t, input, &Request{Format: FormatJXL}).GetExif()
 		&imagerequest.Transform{Format: imagerequest.FormatJXL}).GetExif()
 	for _, field := range []string{
 		"exif-ifd0-Make", "exif-ifd0-Model", "exif-ifd2-BodySerialNumber",
@@ -128,8 +115,7 @@ func TestImageProcessor_JPEGXLDropsSourceResolution(t *testing.T) {
 		t.Fatalf("failed to read test JPEG: %v", err)
 	}
-	output := processAndDecode(t, input,
+	output := processAndDecode(t, input, &Request{Format: FormatJXL})
 		&imagerequest.Transform{Format: imagerequest.FormatJXL})
 	// libvips gives the resolution in pixels per millimetre.
 	xDPI := math.Round(output.ResX() * 25.4)
@@ -154,8 +140,7 @@ func TestImageProcessor_JPEGXLAppliesEXIFOrientation(t *testing.T) {
 		t.Fatalf("failed to read test JPEG: %v", err)
 	}
-	output := processAndDecode(t, input,
+	output := processAndDecode(t, input, &Request{Format: FormatJXL})
 		&imagerequest.Transform{Format: imagerequest.FormatJXL})
 	if output.Width() != 8 || output.Height() != 16 {
 		t.Fatalf("output is %dx%d, want 8x16", output.Width(), output.Height())
@@ -191,8 +176,7 @@ func TestImageProcessor_JPEGXLConvertsWideGamutToSRGB(t *testing.T) {
 		t.Fatalf("failed to read test JPEG: %v", err)
 	}
-	output := processAndDecode(t, input,
+	output := processAndDecode(t, input, &Request{Format: FormatJXL})
 		&imagerequest.Transform{Format: imagerequest.FormatJXL})
 	pixel, err := output.GetPoint(4, 4)
 	if err != nil {
@@ -219,8 +203,7 @@ func TestImageProcessor_JPEGXLFromCMYK(t *testing.T) {
 		t.Fatalf("failed to read test JPEG: %v", err)
 	}
-	output := processAndDecode(t, input,
+	output := processAndDecode(t, input, &Request{Format: FormatJXL})
 		&imagerequest.Transform{Format: imagerequest.FormatJXL})
 	if output.Bands() != 3 {
 		t.Fatalf("output has %d bands, want 3", output.Bands())
@@ -5,13 +5,12 @@ import (
 	"context"
 	"errors"
 	"io"
 	"runtime"
 	"strings"
 	"sync"
 	"testing"
 	"testing/iotest"
 	"time"
 	"sneak.berlin/go/pixa/internal/imagerequest"
 )
 // errTestReadFailed is the error the unreadable test input returns.
@@ -77,13 +76,13 @@ func (r *gatedReader) Read(p []byte) (int, error) {
 	return n, err
 }
-// smallJPEGTransform asks for a 5x5 JPEG.
+// smallJPEGRequest asks for a 5x5 JPEG.
-func smallJPEGTransform() *imagerequest.Transform {
+func smallJPEGRequest() *Request {
-	return &imagerequest.Transform{
+	return &Request{
-		Size:    imagerequest.Size{Width: 5, Height: 5},
+		Size:    Size{Width: 5, Height: 5},
-		Format:  imagerequest.FormatJPEG,
+		Format:  FormatJPEG,
 		Quality: 85,
-		FitMode: imagerequest.FitCover,
+		FitMode: FitCover,
 	}
 }
@@ -93,8 +92,7 @@ func processInBackground(
 	proc *ImageProcessor, reader *gatedReader, results chan<- error,
 ) {
 	go func() {
-		result, err := proc.Process(context.Background(), reader,
+		result, err := proc.Process(context.Background(), reader, smallJPEGRequest())
 			imagerequest.FormatJPEG, smallJPEGTransform())
 		if err == nil {
 			_ = result.Content.Close()
 		}
@@ -117,10 +115,18 @@ func waitForEntries(t *testing.T, entered <-chan struct{}, count int) {
 	}
 }
-func TestNewMakesMaxConcurrentProcessingSlots(t *testing.T) {
+func TestNewDefaultsMaxConcurrentProcessingToCPUs(t *testing.T) {
 	t.Parallel()
-	proc := New(Params{MaxInputBytes: 50 << 20, MaxConcurrentProcessing: 3})
+	for _, limit := range []int{0, -1} {
 		proc := New(Params{MaxConcurrentProcessing: limit})
 		if got := cap(proc.processingSemaphore); got != runtime.GOMAXPROCS(0) {
 			t.Errorf("MaxConcurrentProcessing %d: %d slots, want %d, one per CPU",
 				limit, got, runtime.GOMAXPROCS(0))
 		}
 	}
 	proc := New(Params{MaxConcurrentProcessing: 3})
 	if got := cap(proc.processingSemaphore); got != 3 {
 		t.Errorf("MaxConcurrentProcessing 3: %d slots, want 3", got)
 	}
@@ -139,7 +145,7 @@ func TestProcessNeverExceedsMaxConcurrentProcessing(t *testing.T) {
 		calls = 6
 	)
-	proc := New(Params{MaxInputBytes: 50 << 20, MaxConcurrentProcessing: limit})
+	proc := New(Params{MaxConcurrentProcessing: limit})
 	input := createTestJPEG(t, 50, 50)
 	counter := &readingCounter{}
@@ -186,7 +192,7 @@ func TestProcessNeverExceedsMaxConcurrentProcessing(t *testing.T) {
 func TestProcessWaitsThenFailsWhenNoSlotFrees(t *testing.T) {
 	t.Parallel()
-	proc := New(Params{MaxInputBytes: 50 << 20, MaxConcurrentProcessing: 1})
+	proc := New(Params{MaxConcurrentProcessing: 1})
 	proc.processingWaitTimeout = 100 * time.Millisecond
 	input := createTestJPEG(t, 10, 10)
@@ -207,7 +213,7 @@ func TestProcessWaitsThenFailsWhenNoSlotFrees(t *testing.T) {
 	start := time.Now()
 	_, err := proc.Process(context.Background(), bytes.NewReader(input),
-		imagerequest.FormatJPEG, smallJPEGTransform())
+		smallJPEGRequest())
 	if !errors.Is(err, ErrTooManyImages) {
 		t.Fatalf("Process() error = %v, want ErrTooManyImages", err)
 	}
@@ -233,37 +239,37 @@ func TestProcessReleasesSlotOnError(t *testing.T) {
 	valid := createTestJPEG(t, 10, 10)
-	unsupported := smallJPEGTransform()
+	unsupported := smallJPEGRequest()
 	unsupported.Format = "bmp"
 	cases := []struct {
 		name  string
 		input io.Reader
-		transform *imagerequest.Transform
+		req   *Request
 		// want is the error Process must return; nil means any error.
 		want error
 	}{
 		{
 			name:  "input cannot be read",
 			input: iotest.ErrReader(errTestReadFailed),
-			transform: smallJPEGTransform(),
+			req:   smallJPEGRequest(),
 			want:  errTestReadFailed,
 		},
 		{
 			name:  "input over the byte limit",
 			input: bytes.NewReader(createTestJPEG(t, 800, 600)),
-			transform: smallJPEGTransform(),
+			req:   smallJPEGRequest(),
 			want:  ErrInputDataTooLarge,
 		},
 		{
 			name:  "input not an image",
 			input: strings.NewReader("not an image"),
-			transform: smallJPEGTransform(),
+			req:   smallJPEGRequest(),
 		},
 		{
 			name:  "output format not supported",
 			input: bytes.NewReader(valid),
-			transform: unsupported,
+			req:   unsupported,
 			want:  ErrUnsupportedOutputFormat,
 		},
 	}
@@ -275,8 +281,7 @@ func TestProcessReleasesSlotOnError(t *testing.T) {
 			proc := New(Params{MaxInputBytes: 4096, MaxConcurrentProcessing: 1})
 			proc.processingWaitTimeout = 100 * time.Millisecond
-			_, err := proc.Process(context.Background(), tc.input,
+			_, err := proc.Process(context.Background(), tc.input, tc.req)
 				imagerequest.FormatJPEG, tc.transform)
 			if err == nil || (tc.want != nil && !errors.Is(err, tc.want)) {
 				t.Fatalf("Process() error = %v, want %v", err, tc.want)
 			}
@@ -286,7 +291,7 @@ func TestProcessReleasesSlotOnError(t *testing.T) {
 			}
 			result, err := proc.Process(context.Background(), bytes.NewReader(valid),
-				imagerequest.FormatJPEG, smallJPEGTransform())
+				smallJPEGRequest())
 			if err != nil {
 				t.Fatalf("Process() after the error = %v, want nil", err)
 			}
@@ -303,7 +308,7 @@ func TestProcessReleasesSlotOnError(t *testing.T) {
 func TestWaitForProcessing(t *testing.T) {
 	t.Parallel()
-	proc := New(Params{MaxInputBytes: 50 << 20, MaxConcurrentProcessing: 2})
+	proc := New(Params{MaxConcurrentProcessing: 2})
 	gate := make(chan struct{})
 	entered := make(chan struct{}, 1)
@@ -6,13 +6,11 @@ import (
 	"testing"
 	"github.com/davidbyttow/govips/v2/vips"
 	"sneak.berlin/go/pixa/internal/imagerequest"
 )
 // TestImageProcessor_OrigOfUnnamedFormatRefused verifies that orig of a TIFF
-// input is refused with ErrUnsupportedInputFormat before it is decoded, and
+// input, which is not a source format, is refused with
-// not saved as JPEG. TIFF is not a source format, and the test passes the
+// ErrUnsupportedInputFormat before it is decoded, and not saved as JPEG.
 // input to Process as a JPEG.
 func TestImageProcessor_OrigOfUnnamedFormatRefused(t *testing.T) {
 	t.Parallel()
@@ -28,12 +26,8 @@ func TestImageProcessor_OrigOfUnnamedFormatRefused(t *testing.T) {
 		t.Fatalf("failed to save test TIFF: %v", err)
 	}
-	result, err := New(Params{
+	result, err := New(Params{}).Process(
-		MaxInputBytes:           50 << 20,
+		t.Context(), bytes.NewReader(tiff), &Request{Format: FormatOriginal},
 		MaxConcurrentProcessing: 1,
 	}).Process(
 		t.Context(), bytes.NewReader(tiff), imagerequest.FormatJPEG,
 		&imagerequest.Transform{Format: imagerequest.FormatOriginal},
 	)
 	if result != nil {
 		t.Logf("Process() returned %s", result.ContentType)
@@ -2,11 +2,8 @@ package imageprocessor
 import (
 	"bytes"
 	"errors"
 	"io"
 	"testing"
 	"sneak.berlin/go/pixa/internal/imagerequest"
 )
 // TestImageProcessor_LoadsEachSourceFormat verifies that an image in each of
@@ -15,15 +12,13 @@ import (
 func TestImageProcessor_LoadsEachSourceFormat(t *testing.T) {
 	t.Parallel()
-	proc := New(Params{MaxInputBytes: 50 << 20, MaxConcurrentProcessing: 1})
+	proc := New(Params{})
-	for _, format := range []imagerequest.Format{
+	for _, format := range []Format{
-		imagerequest.FormatJPEG, imagerequest.FormatPNG, imagerequest.FormatGIF,
+		FormatJPEG, FormatPNG, FormatGIF, FormatWebP, FormatAVIF, FormatJXL,
 		imagerequest.FormatWebP, imagerequest.FormatAVIF, imagerequest.FormatJXL,
 	} {
 		saved, err := proc.Process(t.Context(),
-			bytes.NewReader(createTestPNG(t, 20, 20)), imagerequest.FormatPNG,
+			bytes.NewReader(createTestPNG(t, 20, 20)), &Request{Format: format})
 			&imagerequest.Transform{Format: format})
 		if err != nil {
 			t.Fatalf("saving the test image as %s: %v", format, err)
 		}
@@ -33,8 +28,8 @@ func TestImageProcessor_LoadsEachSourceFormat(t *testing.T) {
 			t.Fatalf("reading the %s image: %v", format, err)
 		}
-		result, err := proc.Process(t.Context(), bytes.NewReader(source), format,
+		result, err := proc.Process(t.Context(), bytes.NewReader(source),
-			&imagerequest.Transform{Format: imagerequest.FormatOriginal})
+			&Request{Format: FormatOriginal})
 		if err != nil {
 			t.Errorf("orig of the %s image: %v", format, err)
@@ -43,33 +38,9 @@ func TestImageProcessor_LoadsEachSourceFormat(t *testing.T) {
 		t.Logf("orig of the %s image: %s", format, result.ContentType)
-		if result.ContentType != format.MIMEType() {
+		if result.ContentType != FormatToMIME(format) {
 			t.Errorf("orig of the %s image is %s, want %s",
-				format, result.ContentType, format.MIMEType())
+				format, result.ContentType, FormatToMIME(format))
 		}
 	}
 }
 // TestImageProcessor_NotASourceFormatRefused verifies that a source format
 // other than the seven, such as orig, auto or none, is refused with
 // ErrUnsupportedInputFormat. The input is text, which libvips reads as no
 // format.
 func TestImageProcessor_NotASourceFormatRefused(t *testing.T) {
 	t.Parallel()
 	proc := New(Params{MaxInputBytes: 50 << 20, MaxConcurrentProcessing: 1})
 	for _, sourceFormat := range []imagerequest.Format{
 		imagerequest.FormatOriginal, imagerequest.FormatAuto, "",
 	} {
 		result, err := proc.Process(t.Context(),
 			bytes.NewReader([]byte("this is text, not an image")), sourceFormat,
 			&imagerequest.Transform{Format: imagerequest.FormatJPEG})
 		t.Logf("source format %q: error = %v", sourceFormat, err)
 		if result != nil || !errors.Is(err, ErrUnsupportedInputFormat) {
 			t.Errorf("Process() with source format %q = %v, error %v; want %v",
 				sourceFormat, result, err, ErrUnsupportedInputFormat)
 		}
 	}
 }
@@ -1,255 +0,0 @@
 package imageprocessor
 import (
 	"bytes"
 	"context"
 	"errors"
 	"fmt"
 	"io"
 	"os"
 	"os/exec"
 	"strconv"
 	"syscall"
 	"time"
 	"github.com/davidbyttow/govips/v2/vips"
 )
 // An SVG child process is the running program started again with one of
 // these arguments first, naming what it does. Its command line, after the
 // program's name, is one of:
 //
 //	read-svg-size MEMORY_LIMIT
 //	render-svg-as-png MEMORY_LIMIT WIDTH HEIGHT
 //
 // MEMORY_LIMIT is in bytes. The child reads the SVG on standard input. It
 // writes the SVG's size as WIDTH HEIGHT, or the SVG rendered at WIDTH x
 // HEIGHT as PNG, to standard output.
 const (
 	readSVGSizeArgument    = "read-svg-size"
 	renderSVGAsPNGArgument = "render-svg-as-png"
 )
 // errSVGChildProcessArguments is returned for a command line that is not
 // that of an SVG child process.
 var errSVGChildProcessArguments = errors.New(
 	"not the command line of an SVG child process")
 // IsSVGChildProcess reports whether args, a process's command line after the
 // program's name, are those of an SVG child process.
 func IsSVGChildProcess(args []string) bool {
 	return len(args) > 0 &&
 		(args[0] == readSVGSizeArgument || args[0] == renderSVGAsPNGArgument)
 }
 // RunAsSVGChildProcess runs this process as the SVG child process that args,
 // its command line after the program's name, ask for. It returns the status
 // to exit with: 0 once it has written its result, and 1 after writing an
 // error to standard error, which the parent discards.
 func RunAsSVGChildProcess(args []string) int {
 	err := runAsSVGChildProcess(args, os.Stdin, os.Stdout)
 	if err != nil {
 		_, _ = fmt.Fprintln(os.Stderr, err)
 		return 1
 	}
 	return 0
 }
 // runAsSVGChildProcess does the work of RunAsSVGChildProcess, reading the SVG
 // from stdin and writing the result to stdout. It sets the process's limits
 // before it reads the SVG.
 func runAsSVGChildProcess(
 	args []string, stdin io.Reader, stdout io.Writer,
 ) error {
 	numbers, err := parseSVGChildProcessArguments(args)
 	if err != nil {
 		return err
 	}
 	err = setSVGChildProcessLimits(numbers[0])
 	if err != nil {
 		return err
 	}
 	initVips()
 	svg, err := io.ReadAll(stdin)
 	if err != nil {
 		return fmt.Errorf("failed to read the SVG: %w", err)
 	}
 	if args[0] == readSVGSizeArgument {
 		return writeSVGSize(svg, stdout)
 	}
 	return writeSVGAsPNG(svg, numbers[1], numbers[2], stdout)
 }
 // parseSVGChildProcessArguments returns the numbers on the command line of an
 // SVG child process, args: the memory limit, then the width and height for
 // render-svg-as-png.
 func parseSVGChildProcessArguments(args []string) ([]int, error) {
 	wantArgs := 2
 	if len(args) > 0 && args[0] == renderSVGAsPNGArgument {
 		wantArgs = 4
 	}
 	if !IsSVGChildProcess(args) || len(args) != wantArgs {
 		return nil, fmt.Errorf("%w: %q", errSVGChildProcessArguments, args)
 	}
 	numbers := make([]int, 0, len(args)-1)
 	for _, arg := range args[1:] {
 		number, err := strconv.Atoi(arg)
 		if err != nil {
 			return nil, fmt.Errorf("%w: %q: %w", errSVGChildProcessArguments,
 				args, err)
 		}
 		numbers = append(numbers, number)
 	}
 	return numbers, nil
 }
 // setSVGChildProcessLimits sets this process's RLIMIT_DATA to memoryLimit
 // bytes, so that allocating heap or other private writable memory past it
 // fails. RLIMIT_AS would also count the address space the Go runtime reserves
 // but does not use. It also sets RLIMIT_CORE to 0: librsvg crashes when an
 // allocation fails, and the crash would write a core file of up to
 // memoryLimit bytes into pixad's working directory.
 func setSVGChildProcessLimits(memoryLimit int) error {
 	if memoryLimit < 1 {
 		return fmt.Errorf("%w: memory limit %d", errSVGChildProcessArguments,
 			memoryLimit)
 	}
 	err := syscall.Setrlimit(syscall.RLIMIT_DATA, &syscall.Rlimit{
 		Cur: uint64(memoryLimit),
 		Max: uint64(memoryLimit),
 	})
 	if err != nil {
 		return fmt.Errorf("failed to limit memory to %d bytes: %w",
 			memoryLimit, err)
 	}
 	err = syscall.Setrlimit(syscall.RLIMIT_CORE, &syscall.Rlimit{})
 	if err != nil {
 		return fmt.Errorf("failed to turn off core files: %w", err)
 	}
 	return nil
 }
 // writeSVGSize writes the size of svg to stdout as WIDTH HEIGHT. librsvg
 // reads the whole SVG for it.
 func writeSVGSize(svg []byte, stdout io.Writer) error {
 	img, err := vips.NewImageFromBuffer(svg)
 	if err != nil {
 		return fmt.Errorf("failed to read the SVG: %w", err)
 	}
 	defer img.Close()
 	_, err = fmt.Fprintf(stdout, "%d %d\n", img.Width(), img.Height())
 	return err
 }
 // writeSVGAsPNG renders svg at width x height and writes it to stdout as PNG.
 // libvips' thumbnail has librsvg render the SVG at that size directly, at
 // any scale: govips takes a density only in whole dots per inch, which cannot
 // render an SVG below 1/72 of its own size. Given the SVG as bytes with no
 // file name, librsvg loads no file or URL the SVG refers to.
 func writeSVGAsPNG(svg []byte, width, height int, stdout io.Writer) error {
 	img, err := vips.NewThumbnailWithSizeFromBuffer(svg, width, height,
 		vips.InterestingNone, vips.SizeBoth)
 	if err != nil {
 		return fmt.Errorf("failed to render the SVG: %w", err)
 	}
 	defer img.Close()
 	png, err := exportPNG(img)
 	if err != nil {
 		return fmt.Errorf("failed to save the SVG as PNG: %w", err)
 	}
 	_, err = stdout.Write(png)
 	return err
 }
 // readSVGSize reads the size of the SVG data in a child process that pixa
 // kills at deadline (see runSVGChildProcess).
 func (p *ImageProcessor) readSVGSize(
 	ctx context.Context, deadline time.Time, data []byte,
 ) (int, int, error) {
 	output, err := p.runSVGChildProcess(ctx, deadline, data,
 		readSVGSizeArgument)
 	if err != nil {
 		return 0, 0, err
 	}
 	var width, height int
 	_, err = fmt.Sscan(string(output), &width, &height)
 	if err != nil {
 		return 0, 0, fmt.Errorf("failed to read the size %q an SVG child "+
 			"process wrote: %w", output, err)
 	}
 	return width, height, nil
 }
 // runSVGChildProcess starts the running program again as an SVG child
 // process, with argument, p.maxSVGRenderMemory and extraArgs as its command
 // line, and waits for it. It gives the child data on standard input,
 // discards its standard error, and returns its standard output. pixa kills
 // the child at deadline. A child that fails or is killed is
 // ErrSVGRenderFailed, unless ctx has ended: runSVGChildProcess then returns
 // ctx's error. Failing to start the child is another error.
 func (p *ImageProcessor) runSVGChildProcess(
 	ctx context.Context, deadline time.Time, data []byte,
 	argument string, extraArgs ...string,
 ) ([]byte, error) {
 	executable, err := os.Executable()
 	if err != nil {
 		return nil, fmt.Errorf("failed to find the running program: %w", err)
 	}
 	childCtx, cancel := context.WithDeadline(ctx, deadline)
 	defer cancel()
 	args := append([]string{argument, strconv.Itoa(p.maxSVGRenderMemory)},
 		extraArgs...)
 	//nolint:gosec // the running program, with arguments pixa makes
 	cmd := exec.CommandContext(childCtx, executable, args...)
 	cmd.Stdin = bytes.NewReader(data)
 	var stdout bytes.Buffer
 	cmd.Stdout = &stdout
 	err = cmd.Run()
 	var exitError *exec.ExitError
 	switch {
 	case err == nil:
 		return stdout.Bytes(), nil
 	case ctx.Err() != nil:
 		return nil, ctx.Err()
 	case childCtx.Err() != nil:
 		return nil, fmt.Errorf("%w: it took more than %v", ErrSVGRenderFailed,
 			p.svgRenderTimeout)
 	case errors.As(err, &exitError):
 		return nil, fmt.Errorf("%w: %w", ErrSVGRenderFailed, err)
 	default:
 		return nil, fmt.Errorf("failed to run an SVG child process: %w", err)
 	}
 }
@@ -1,503 +0,0 @@
 package imageprocessor
 import (
 	"bytes"
 	"errors"
 	"fmt"
 	"io"
 	"net/http"
 	"net/http/httptest"
 	"os"
 	"path/filepath"
 	"strings"
 	"sync/atomic"
 	"testing"
 	"time"
 	"github.com/davidbyttow/govips/v2/vips"
 	"sneak.berlin/go/pixa/internal/imagerequest"
 )
 // testSVG is a 16x12 SVG, black on its left half and white on its right.
 const testSVG = `<svg xmlns="http://www.w3.org/2000/svg" width="16" height="12">` +
 	`<rect width="16" height="12" fill="white"/>` +
 	`<rect width="8" height="12" fill="black"/></svg>`
 // newSVGTestProcessor returns a processor for the SVG tests.
 func newSVGTestProcessor() *ImageProcessor {
 	return New(Params{MaxInputBytes: 1 << 20, MaxConcurrentProcessing: 1})
 }
 // processSVG processes svg, as an SVG source, with transform.
 func processSVG(
 	t *testing.T, svg string, transform imagerequest.Transform,
 ) (*Result, []byte, error) {
 	t.Helper()
 	result, err := newSVGTestProcessor().Process(t.Context(),
 		bytes.NewReader([]byte(svg)), imagerequest.FormatSVG, &transform)
 	if err != nil {
 		return nil, nil, err
 	}
 	output, err := io.ReadAll(result.Content)
 	if err != nil {
 		t.Fatalf("reading the output: %v", err)
 	}
 	return result, output, nil
 }
 // TestImageProcessor_SVGOrigIsTheSVG checks that orig of an SVG at the orig
 // size is the SVG itself, never another format, and that orig at another
 // size is ErrSVGNotOriginalSize.
 func TestImageProcessor_SVGOrigIsTheSVG(t *testing.T) {
 	t.Parallel()
 	result, output, err := processSVG(t, testSVG,
 		imagerequest.Transform{Format: imagerequest.FormatOriginal})
 	if err != nil {
 		t.Fatalf("orig of the SVG: %v", err)
 	}
 	t.Logf("orig of the SVG: %s, %dx%d", result.ContentType, result.Width,
 		result.Height)
 	if result.ContentType != "image/svg+xml" || string(output) != testSVG {
 		t.Errorf("orig of the SVG = %s %q, want image/svg+xml %q",
 			result.ContentType, output, testSVG)
 	}
 	_, _, err = processSVG(t, testSVG, imagerequest.Transform{
 		Size:   imagerequest.Size{Width: 32, Height: 24},
 		Format: imagerequest.FormatOriginal,
 	})
 	if !errors.Is(err, ErrSVGNotOriginalSize) {
 		t.Errorf("orig of the SVG at 32x24: error = %v, want %v", err,
 			ErrSVGNotOriginalSize)
 	}
 }
 // TestImageProcessor_RendersSVGToEachRasterFormat checks that an SVG is
 // rendered to each raster format at the requested size.
 func TestImageProcessor_RendersSVGToEachRasterFormat(t *testing.T) {
 	t.Parallel()
 	for _, format := range []imagerequest.Format{
 		imagerequest.FormatJPEG, imagerequest.FormatPNG, imagerequest.FormatGIF,
 		imagerequest.FormatWebP, imagerequest.FormatAVIF, imagerequest.FormatJXL,
 	} {
 		result, output, err := processSVG(t, testSVG, imagerequest.Transform{
 			Size:   imagerequest.Size{Width: 40, Height: 30},
 			Format: format,
 		})
 		if err != nil {
 			t.Errorf("SVG as %s: %v", format, err)
 			continue
 		}
 		t.Logf("SVG as %s: %s, %dx%d, %d bytes", format, result.ContentType,
 			result.Width, result.Height, len(output))
 		if result.ContentType != format.MIMEType() ||
 			vips.DetermineImageType(output) != vipsImageType(format) ||
 			result.Width != 40 || result.Height != 30 {
 			t.Errorf("SVG as %s = %s, %dx%d; want %s, 40x30", format,
 				result.ContentType, result.Width, result.Height, format.MIMEType())
 		}
 	}
 }
 // TestImageProcessor_RendersSVGSharpWhenEnlarged checks that a 16x12 SVG
 // asked for at 1600x1200 is rendered at that size, not rendered at 16x12 and
 // enlarged: 10 pixels either side of the edge between its black and white
 // halves are black and white, where an enlarged image is grey there.
 func TestImageProcessor_RendersSVGSharpWhenEnlarged(t *testing.T) {
 	t.Parallel()
 	_, output, err := processSVG(t, testSVG, imagerequest.Transform{
 		Size:   imagerequest.Size{Width: 1600, Height: 1200},
 		Format: imagerequest.FormatPNG,
 	})
 	if err != nil {
 		t.Fatalf("SVG as PNG at 1600x1200: %v", err)
 	}
 	img, err := vips.NewImageFromBuffer(output)
 	if err != nil {
 		t.Fatalf("decoding the PNG: %v", err)
 	}
 	t.Cleanup(img.Close)
 	for x, want := range map[int]float64{790: 0, 810: 255} {
 		point, err := img.GetPoint(x, 600)
 		if err != nil {
 			t.Fatalf("GetPoint(%d, 600): %v", x, err)
 		}
 		t.Logf("pixel at %d,600: %v", x, point)
 		if point[0] != want {
 			t.Errorf("pixel at %d,600 = %v, want %v", x, point[0], want)
 		}
 	}
 }
 // TestImageProcessor_SVGFetchesNothing checks that rendering an SVG draws no
 // image it refers to: one at a URL on a local server, by href or xlink:href,
 // or a local file that exists. Each SVG renders without error, white where
 // the image would be. An SVG that uses an external entity at that server is
 // a separate case. No SVG makes a request to the server.
 func TestImageProcessor_SVGFetchesNothing(t *testing.T) {
 	t.Parallel()
 	var requests atomic.Int64
 	// Blue is 128 in every pixel of this PNG.
 	png := createTestPNG(t, 4, 4)
 	server := httptest.NewServer(http.HandlerFunc(
 		func(w http.ResponseWriter, r *http.Request) {
 			requests.Add(1)
 			t.Logf("request for %s", r.URL)
 			w.Header().Set("Content-Type", "image/png")
 			_, _ = w.Write(png)
 		}))
 	t.Cleanup(server.Close)
 	pngPath := filepath.Join(t.TempDir(), "image.png")
 	err := os.WriteFile(pngPath, png, 0o600)
 	if err != nil {
 		t.Fatalf("writing the PNG file: %v", err)
 	}
 	for _, reference := range []string{
 		`href="` + server.URL + `/image.png"`,
 		`xlink:href="` + server.URL + `/xlink.png"`,
 		`href="file://` + pngPath + `"`,
 	} {
 		svg := `<svg xmlns="http://www.w3.org/2000/svg" ` +
 			`xmlns:xlink="http://www.w3.org/1999/xlink" width="16" height="12">` +
 			`<rect width="16" height="12" fill="white"/>` +
 			`<image ` + reference + ` width="16" height="12"/></svg>`
 		_, output, err := processSVG(t, svg, imagerequest.Transform{
 			Format: imagerequest.FormatPNG,
 		})
 		if err != nil {
 			t.Errorf("SVG with image %s as PNG: %v", reference, err)
 			continue
 		}
 		img, err := vips.NewImageFromBuffer(output)
 		if err != nil {
 			t.Fatalf("decoding the PNG: %v", err)
 		}
 		point, err := img.GetPoint(8, 6)
 		img.Close()
 		if err != nil {
 			t.Fatalf("GetPoint(8, 6): %v", err)
 		}
 		t.Logf("SVG with image %s: pixel at 8,6 = %v", reference, point)
 		if point[2] != 255 {
 			t.Errorf("SVG with image %s: blue at 8,6 = %v, want 255: the "+
 				"image is drawn", reference, point[2])
 		}
 	}
 	svg := `<?xml version="1.0"?>` +
 		`<!DOCTYPE svg [<!ENTITY outside SYSTEM "` + server.URL + `/entity">]>` +
 		`<svg xmlns="http://www.w3.org/2000/svg" width="16" height="12">` +
 		`<text y="10">&outside;</text></svg>`
 	// librsvg loads no external entity, so it refuses this SVG: outside is
 	// not defined.
 	_, _, err = processSVG(t, svg, imagerequest.Transform{
 		Format: imagerequest.FormatPNG,
 	})
 	t.Logf("SVG with an external entity as PNG: error = %v", err)
 	if requests.Load() != 0 {
 		t.Errorf("rendering the SVGs made %d requests, want none",
 			requests.Load())
 	}
 }
 // TestImageProcessor_RendersSVGLargerThanMaxInputDimension checks that an
 // SVG whose own size is above MaxInputDimension is limited only by the
 // output checks: it is rendered at a raster size, orig of it is the SVG
 // itself, and a raster format at its own size is ErrSVGTooLargeForOrigSize.
 // The 1000000x1000000 one is rendered at a ten-thousandth of its own size.
 func TestImageProcessor_RendersSVGLargerThanMaxInputDimension(t *testing.T) {
 	t.Parallel()
 	for _, svg := range []string{
 		`<svg xmlns="http://www.w3.org/2000/svg" width="10000" height="10">` +
 			`<rect width="10000" height="10"/></svg>`,
 		`<svg xmlns="http://www.w3.org/2000/svg" width="1000000" ` +
 			`height="1000000"><rect width="1000000" height="1000000"/></svg>`,
 	} {
 		result, _, err := processSVG(t, svg, imagerequest.Transform{
 			Size:   imagerequest.Size{Width: 100, Height: 100},
 			Format: imagerequest.FormatPNG,
 		})
 		if err != nil {
 			t.Errorf("%s as PNG at 100x100: %v", svg, err)
 		} else {
 			t.Logf("%s as PNG at 100x100: %dx%d", svg, result.Width, result.Height)
 			if result.Width != 100 || result.Height != 100 {
 				t.Errorf("%s as PNG at 100x100 = %dx%d, want 100x100", svg,
 					result.Width, result.Height)
 			}
 		}
 		result, output, err := processSVG(t, svg,
 			imagerequest.Transform{Format: imagerequest.FormatOriginal})
 		if err != nil || result.ContentType != imagerequest.FormatSVG.MIMEType() ||
 			string(output) != svg {
 			t.Errorf("orig of %s: error = %v, want the SVG itself", svg, err)
 		}
 		_, _, err = processSVG(t, svg,
 			imagerequest.Transform{Format: imagerequest.FormatPNG})
 		if !errors.Is(err, ErrSVGTooLargeForOrigSize) {
 			t.Errorf("%s as PNG at its own size: error = %v, want %v", svg,
 				err, ErrSVGTooLargeForOrigSize)
 		}
 	}
 }
 // TestImageProcessor_RefusesSVGTooThin checks that an SVG with one side more
 // than MaxInputDimension times the other is ErrSVGTooThin at a raster size,
 // that one at exactly that proportion is rendered, and that orig of either
 // is the SVG itself.
 func TestImageProcessor_RefusesSVGTooThin(t *testing.T) {
 	t.Parallel()
 	tooThin := `<svg xmlns="http://www.w3.org/2000/svg" width="81930" ` +
 		`height="10"><rect width="81930" height="10"/></svg>`
 	atTheLimit := `<svg xmlns="http://www.w3.org/2000/svg" width="81920" ` +
 		`height="10"><rect width="81920" height="10"/></svg>`
 	size := imagerequest.Size{Width: 100, Height: 100}
 	_, _, err := processSVG(t, tooThin,
 		imagerequest.Transform{Size: size, Format: imagerequest.FormatPNG})
 	if !errors.Is(err, ErrSVGTooThin) {
 		t.Errorf("81930x10 SVG as PNG at 100x100: error = %v, want %v", err,
 			ErrSVGTooThin)
 	}
 	result, _, err := processSVG(t, atTheLimit,
 		imagerequest.Transform{Size: size, Format: imagerequest.FormatPNG})
 	if err != nil {
 		t.Errorf("81920x10 SVG as PNG at 100x100: %v", err)
 	} else if result.Width != 100 || result.Height != 100 {
 		t.Errorf("81920x10 SVG as PNG at 100x100 = %dx%d, want 100x100",
 			result.Width, result.Height)
 	}
 	for _, svg := range []string{tooThin, atTheLimit} {
 		result, output, err := processSVG(t, svg,
 			imagerequest.Transform{Format: imagerequest.FormatOriginal})
 		if err != nil || result.ContentType != imagerequest.FormatSVG.MIMEType() ||
 			string(output) != svg {
 			t.Errorf("orig of %s: error = %v, want the SVG itself", svg, err)
 		}
 	}
 }
 // testSVGRenderTimeout is the time limit of the SVG time limit tests, short
 // so that they finish in a few seconds. Under the race detector a child
 // process takes about a second to start and read an SVG's size.
 const testSVGRenderTimeout = 3 * time.Second
 // processSVGTimed has processor process svg, as an SVG source, with transform,
 // and returns the error and how long it took.
 func processSVGTimed(
 	t *testing.T, processor *ImageProcessor, svg string,
 	transform imagerequest.Transform,
 ) (time.Duration, error) {
 	t.Helper()
 	start := time.Now()
 	_, err := processor.Process(t.Context(), strings.NewReader(svg),
 		imagerequest.FormatSVG, &transform)
 	return time.Since(start), err
 }
 // checkProcessesAnotherImage checks that processor, after refusing an SVG,
 // processes a PNG.
 func checkProcessesAnotherImage(t *testing.T, processor *ImageProcessor) {
 	t.Helper()
 	_, err := processor.Process(t.Context(),
 		bytes.NewReader(createTestPNG(t, 64, 48)), imagerequest.FormatPNG,
 		&imagerequest.Transform{
 			Size:   imagerequest.Size{Width: 32, Height: 24},
 			Format: imagerequest.FormatJPEG,
 		})
 	if err != nil {
 		t.Errorf("a PNG after the SVG: %v", err)
 	}
 }
 // TestImageProcessor_StopsSlowSVGRender checks that an SVG that takes about
 // 12 seconds to render, 600 shapes each drawn with an feTurbulence filter
 // effect, is ErrSVGRenderFailed soon after a time limit of
 // testSVGRenderTimeout, not when the render would end. The processor then
 // processes another image.
 func TestImageProcessor_StopsSlowSVGRender(t *testing.T) {
 	t.Parallel()
 	svg := `<svg xmlns="http://www.w3.org/2000/svg" width="256" height="256">` +
 		`<filter id="noise">` +
 		`<feTurbulence baseFrequency="0.05" numOctaves="4"/></filter>` +
 		strings.Repeat(`<rect width="256" height="256" filter="url(#noise)"/>`,
 			600) +
 		`</svg>`
 	processor := newSVGTestProcessor()
 	processor.svgRenderTimeout = testSVGRenderTimeout
 	elapsed, err := processSVGTimed(t, processor, svg, imagerequest.Transform{
 		Size:   imagerequest.Size{Width: 256, Height: 256},
 		Format: imagerequest.FormatPNG,
 	})
 	t.Logf("slow SVG as PNG: error %v after %v", err, elapsed)
 	if !errors.Is(err, ErrSVGRenderFailed) {
 		t.Errorf("slow SVG as PNG: error = %v, want %v", err,
 			ErrSVGRenderFailed)
 	}
 	if elapsed > testSVGRenderTimeout+2*time.Second {
 		t.Errorf("slow SVG as PNG: refused after %v, want soon after %v",
 			elapsed, testSVGRenderTimeout)
 	}
 	checkProcessesAnotherImage(t, processor)
 }
 // TestImageProcessor_StopsSlowSVGSizeRead checks that orig of an SVG whose
 // size takes about 10 seconds to read is ErrSVGRenderFailed soon after a time
 // limit of testSVGRenderTimeout. To read the size, librsvg matches each of the
 // SVG's 2500 CSS rules against each of its 2500 shapes, walking up the 75
 // groups around it. The processor then processes another image.
 func TestImageProcessor_StopsSlowSVGSizeRead(t *testing.T) {
 	t.Parallel()
 	var rules strings.Builder
 	for i := range 2500 {
 		fmt.Fprintf(&rules, ".group%d rect { fill: red }", i)
 	}
 	svg := `<svg xmlns="http://www.w3.org/2000/svg" width="16" height="12">` +
 		`<style>` + rules.String() + `</style>` + strings.Repeat(`<g>`, 75) +
 		strings.Repeat(`<rect width="1" height="1"/>`, 2500) +
 		strings.Repeat(`</g>`, 75) + `</svg>`
 	processor := newSVGTestProcessor()
 	processor.svgRenderTimeout = testSVGRenderTimeout
 	elapsed, err := processSVGTimed(t, processor, svg,
 		imagerequest.Transform{Format: imagerequest.FormatOriginal})
 	t.Logf("orig of the SVG: error %v after %v", err, elapsed)
 	if !errors.Is(err, ErrSVGRenderFailed) {
 		t.Errorf("orig of the SVG: error = %v, want %v", err,
 			ErrSVGRenderFailed)
 	}
 	if elapsed > testSVGRenderTimeout+2*time.Second {
 		t.Errorf("orig of the SVG: refused after %v, want soon after %v",
 			elapsed, testSVGRenderTimeout)
 	}
 	checkProcessesAnotherImage(t, processor)
 }
 // TestImageProcessor_StopsSVGRenderOverMemoryLimit checks that an SVG that
 // needs about 500 MiB more than a child process's own memory to render, a
 // chain of 2000 blurs that each keep their result, is ErrSVGRenderFailed with
 // a memory limit of 512 MiB, and that a plain SVG renders under the same
 // limit. A child process needs about 130 MiB of its own, and about 350 MiB
 // under the race detector, so the chain also renders under MaxSVGRenderMemory.
 func TestImageProcessor_StopsSVGRenderOverMemoryLimit(t *testing.T) {
 	t.Parallel()
 	var blurs strings.Builder
 	blurs.WriteString(`<feGaussianBlur stdDeviation="3" result="blur0"/>`)
 	for i := 1; i < 2000; i++ {
 		fmt.Fprintf(&blurs,
 			`<feGaussianBlur in="blur%d" stdDeviation="3" result="blur%d"/>`,
 			i-1, i)
 	}
 	svg := `<svg xmlns="http://www.w3.org/2000/svg" width="256" height="256">` +
 		`<filter id="blurs" color-interpolation-filters="sRGB">` +
 		blurs.String() + `</filter>` +
 		`<rect width="256" height="256" fill="red" filter="url(#blurs)"/></svg>`
 	size := imagerequest.Size{Width: 256, Height: 256}
 	processor := newSVGTestProcessor()
 	processor.maxSVGRenderMemory = 512 << 20
 	elapsed, err := processSVGTimed(t, processor, svg,
 		imagerequest.Transform{Size: size, Format: imagerequest.FormatPNG})
 	t.Logf("SVG of 2000 blurs as PNG: error %v after %v", err, elapsed)
 	if !errors.Is(err, ErrSVGRenderFailed) {
 		t.Errorf("SVG of 2000 blurs as PNG: error = %v, want %v", err,
 			ErrSVGRenderFailed)
 	}
 	_, err = processSVGTimed(t, processor, testSVG,
 		imagerequest.Transform{Size: size, Format: imagerequest.FormatPNG})
 	if err != nil {
 		t.Errorf("plain SVG as PNG after it: %v", err)
 	}
 }
 // TestSVGRenderSize checks the size at which an SVG is rendered to cover an
 // output size, and that it is held to MaxInputDimension.
 func TestSVGRenderSize(t *testing.T) {
 	t.Parallel()
 	tests := []struct {
 		name                      string
 		width, height             int
 		outputWidth, outputHeight int
 		wantWidth, wantHeight     int
 	}{
 		{"own size", 16, 12, 16, 12, 16, 12},
 		{"100 times larger", 16, 12, 1600, 1200, 1600, 1200},
 		{"wider than the SVG's proportions", 16, 12, 160, 12, 160, 120},
 		{"10 times smaller", 100, 100, 10, 10, 10, 10},
 		{"held to MaxInputDimension", 8192, 1, 8192, 8192, 8192, 1},
 		{"held to MaxInputDimension when enlarged", 1024, 1, 8192, 8192, 8192, 8},
 		{"far above MaxInputDimension", 1000000, 1000000, 100, 100, 100, 100},
 	}
 	for _, tt := range tests {
 		gotWidth, gotHeight := svgRenderSize(tt.width, tt.height,
 			tt.outputWidth, tt.outputHeight)
 		if gotWidth != tt.wantWidth || gotHeight != tt.wantHeight {
 			t.Errorf("%s: svgRenderSize(%d, %d, %d, %d) = %dx%d, want %dx%d",
 				tt.name, tt.width, tt.height, tt.outputWidth, tt.outputHeight,
 				gotWidth, gotHeight, tt.wantWidth, tt.wantHeight)
 		}
 	}
 }
@@ -1,100 +0,0 @@
 package imageproxy
 import (
 	"bytes"
 	"os"
 	"testing"
 	"time"
 	"sneak.berlin/go/pixa/internal/imagerequest"
 	"sneak.berlin/go/pixa/internal/imgcache"
 )
 // TestProxy_Get_MakesAgainVariantOfNoOutputFormat replaces a cached
 // variant's file with text, and checks that the next request is a miss
 // answered with the variant made again, and the one after a hit.
 func TestProxy_Get_MakesAgainVariantOfNoOutputFormat(t *testing.T) {
 	t.Parallel()
 	svc, fixtures := setupTestProxy(t)
 	req := photoVariant(fixtures, 85, imagerequest.FitCover)
 	want, _ := getImage(t, svc, req)
 	path := variantFilePath(svc, imagerequest.CacheKey(req))
 	err := os.WriteFile(path, []byte("this is text, not an image"),
 		imgcache.StorageFilePerm)
 	if err != nil {
 		t.Fatalf("replacing the variant file: %v", err)
 	}
 	got, status := getImage(t, svc, req)
 	t.Logf("after the replacement: %d bytes, %s", len(got), status)
 	if status != CacheMiss || !bytes.Equal(got, want) {
 		t.Errorf("after the replacement: Get() = %d bytes, %s; want the %d bytes "+
 			"made again, %s", len(got), status, len(want), CacheMiss)
 	}
 	got, status = getImage(t, svc, req)
 	if status != CacheHit || !bytes.Equal(got, want) {
 		t.Errorf("next request: Get() = %d bytes, %s; want the %d bytes, %s",
 			len(got), status, len(want), CacheHit)
 	}
 }
 // TestProxy_Get_HitWaitsForNoDatabaseWrite holds the database's one
 // connection while a cached variant is requested. The hit must be answered
 // while the connection is still held, and its access time must reach the
 // database once it is free.
 func TestProxy_Get_HitWaitsForNoDatabaseWrite(t *testing.T) {
 	t.Parallel()
 	svc, fixtures := setupTestProxy(t)
 	req := photoVariant(fixtures, 85, imagerequest.FitCover)
 	key := imagerequest.CacheKey(req)
 	getImage(t, svc, req)
 	// Each connection to an in-memory SQLite database opens a new, empty one,
 	// so the goroutine that writes the access times must share the
 	// connection that holds the schema.
 	svc.db.SetMaxOpenConns(1)
 	svc.cache.StartPendingAccessTimeWrites()
 	defer func() { _ = svc.cache.StopPendingAccessTimeWrites(t.Context()) }()
 	anHourAgo := time.Now().Add(-time.Hour)
 	setVariantLastAccessed(t, svc.db, key, anHourAgo)
 	releaseDatabase := holdDatabase(t, svc.db)
 	defer releaseDatabase()
 	results := startGet(t.Context(), svc, req)
 	select {
 	case got := <-results:
 		if got.err != nil {
 			t.Fatalf("Get() of the cached variant error = %v", got.err)
 		}
 	case <-time.After(pendingAccessTimesWait):
 		t.Fatal("the cache hit waited for the database")
 	}
 	releaseDatabase()
 	deadline := time.Now().Add(pendingAccessTimesWait)
 	for countRows(t, svc.db, `
 		SELECT COUNT(*) FROM variant_content
 		WHERE cache_key = ? AND last_accessed_at > ?
 	`, string(key), anHourAgo.UTC().Format(sqliteTimestampFormat)) == 0 {
 		if time.Now().After(deadline) {
 			t.Fatal("the hit's access time was not written")
 		}
 		time.Sleep(10 * time.Millisecond)
 	}
 }
@@ -1,493 +0,0 @@
 package imageproxy
 import (
 	"bytes"
 	"context"
 	"errors"
 	"fmt"
 	"image/color"
 	"io"
 	"net/http"
 	"os"
 	"sync"
 	"testing"
 	"time"
 	"sneak.berlin/go/pixa/internal/httpfetcher"
 	"sneak.berlin/go/pixa/internal/imagerequest"
 )
 // Validators the test upstream sends with its image.
 const (
 	testETag         = `"v1"`
 	testLastModified = "Mon, 02 Nov 2026 10:00:00 GMT"
 )
 // errConnectionRefused stands for an upstream that cannot be reached.
 var errConnectionRefused = errors.New("connection refused")
 // upstreamFailure is one way a fetch from upstream fails.
 type upstreamFailure struct {
 	name string
 	err  error
 }
 // upstreamFailures returns the ways a check of a cached image with upstream
 // can fail: an error status, a timeout and no connection.
 func upstreamFailures() []upstreamFailure {
 	return []upstreamFailure{
 		{"error status", fmt.Errorf("%w: status 503", httpfetcher.ErrUpstreamError)},
 		{"timeout", httpfetcher.ErrUpstreamTimeout},
 		{"no connection", errConnectionRefused},
 	}
 }
 // conditionalUpstream serves one JPEG image with an ETag or a Last-Modified
 // header, or both. It answers 304 Not Modified to a fetch whose If-None-Match
 // is its ETag, or, when it has no ETag, whose If-Modified-Since is its
 // Last-Modified. While err is set, every fetch fails with it. It records the
 // conditional headers of every fetch.
 type conditionalUpstream struct {
 	mu           sync.Mutex
 	image        []byte
 	etag         string
 	lastModified string
 	err          error
 	ifNoneMatch     []string
 	ifModifiedSince []string
 }
 func (u *conditionalUpstream) Fetch(
 	_ context.Context, _ imagerequest.Source,
 	ifNoneMatch, ifModifiedSince string,
 ) (*httpfetcher.FetchResult, error) {
 	u.mu.Lock()
 	defer u.mu.Unlock()
 	u.ifNoneMatch = append(u.ifNoneMatch, ifNoneMatch)
 	u.ifModifiedSince = append(u.ifModifiedSince, ifModifiedSince)
 	if u.err != nil {
 		return nil, u.err
 	}
 	unchanged := ifNoneMatch == u.etag
 	if u.etag == "" {
 		unchanged = ifModifiedSince == u.lastModified
 	}
 	if unchanged {
 		return &httpfetcher.FetchResult{
 			Content:    http.NoBody,
 			StatusCode: http.StatusNotModified,
 		}, nil
 	}
 	headers := http.Header{}
 	if u.etag != "" {
 		headers.Set("ETag", u.etag)
 	}
 	if u.lastModified != "" {
 		headers.Set("Last-Modified", u.lastModified)
 	}
 	return &httpfetcher.FetchResult{
 		Content:       io.NopCloser(bytes.NewReader(u.image)),
 		ContentLength: int64(len(u.image)),
 		ContentType:   testContentTypeJPEG,
 		Headers:       headers,
 		StatusCode:    http.StatusOK,
 	}, nil
 }
 // change replaces the upstream image and its ETag.
 func (u *conditionalUpstream) change(image []byte, etag string) {
 	u.mu.Lock()
 	defer u.mu.Unlock()
 	u.image = image
 	u.etag = etag
 }
 // fail makes every later fetch fail with err.
 func (u *conditionalUpstream) fail(err error) {
 	u.mu.Lock()
 	defer u.mu.Unlock()
 	u.err = err
 }
 // fetches returns how many fetches upstream was asked for.
 func (u *conditionalUpstream) fetches() int {
 	u.mu.Lock()
 	defer u.mu.Unlock()
 	return len(u.ifNoneMatch)
 }
 // lastConditionalHeaders returns the If-None-Match and If-Modified-Since of
 // the last fetch.
 func (u *conditionalUpstream) lastConditionalHeaders() (string, string) {
 	u.mu.Lock()
 	defer u.mu.Unlock()
 	last := len(u.ifNoneMatch) - 1
 	return u.ifNoneMatch[last], u.ifModifiedSince[last]
 }
 // setupConditionalUpstreamProxy returns a proxy whose upstream is a
 // conditionalUpstream serving a red JPEG with an ETag.
 func setupConditionalUpstreamProxy(
 	t *testing.T,
 ) (*testProxy, *TestFixtures, *conditionalUpstream) {
 	t.Helper()
 	svc, fixtures := setupTestProxy(t)
 	upstream := &conditionalUpstream{
 		image: generateTestJPEG(t, 100, 100, color.RGBA{255, 0, 0, 255}),
 		etag:  testETag,
 	}
 	svc.fetcher = upstream
 	return svc, fixtures, upstream
 }
 // TestProxy_Get_FreshVariantAsksUpstreamNothing checks that a variant whose
 // source was checked with upstream less than the cache TTL ago is served from
 // the cache without asking upstream.
 func TestProxy_Get_FreshVariantAsksUpstreamNothing(t *testing.T) {
 	t.Parallel()
 	svc, fixtures, upstream := setupConditionalUpstreamProxy(t)
 	variant := photoVariant(fixtures, 85, imagerequest.FitCover)
 	first, _ := getImage(t, svc, variant)
 	second, status := getImage(t, svc, variant)
 	t.Logf("cache status = %s, upstream fetches = %d", status, upstream.fetches())
 	if status != CacheHit {
 		t.Errorf("CacheStatus = %q, want %q", status, CacheHit)
 	}
 	if !bytes.Equal(first, second) {
 		t.Error("the cached variant differs from the one first served")
 	}
 	if n := upstream.fetches(); n != 1 {
 		t.Errorf("upstream fetches = %d, want 1", n)
 	}
 }
 // TestProxy_Get_UnchangedSourceAfterTTLIsNotDownloadedAgain caches a variant,
 // sets its source's check time and the variant's file time two days back,
 // and requests it again, with the source still cached and with the source's
 // row and file removed, as eviction does. Upstream must be asked with the
 // validator it sent, answer 304, and send no bytes; the variant must be served
 // again without being made again, and then be served from the cache until the
 // TTL passes.
 func TestProxy_Get_UnchangedSourceAfterTTLIsNotDownloadedAgain(t *testing.T) {
 	t.Parallel()
 	tests := []struct {
 		name                string
 		sourceEvicted       bool
 		etag                string
 		lastModified        string
 		wantIfNoneMatch     string
 		wantIfModifiedSince string
 	}{
 		{"ETag", false, testETag, "", testETag, ""},
 		{"Last-Modified only", false, "", testLastModified, "", testLastModified},
 		{"both", false, testETag, testLastModified, testETag, testLastModified},
 		{"ETag, source evicted", true, testETag, "", testETag, ""},
 		{"Last-Modified only, source evicted", true, "", testLastModified, "",
 			testLastModified},
 		{"both, source evicted", true, testETag, testLastModified, testETag,
 			testLastModified},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			svc, fixtures, upstream := setupConditionalUpstreamProxy(t)
 			upstream.etag = tt.etag
 			upstream.lastModified = tt.lastModified
 			variant := photoVariant(fixtures, 85, imagerequest.FitCover)
 			first, _ := getImage(t, svc, variant)
 			setBackSourceAndVariant(t, svc, variant, time.Now().AddDate(0, 0, -2))
 			if tt.sourceEvicted {
 				evictSource(t, svc, variant.Source)
 			}
 			second, status := getImage(t, svc, variant)
 			ifNoneMatch, ifModifiedSince := upstream.lastConditionalHeaders()
 			counters := readCounters(t, svc)
 			t.Logf("cache status = %s, If-None-Match = %q, If-Modified-Since = %q, "+
 				"counters = %+v", status, ifNoneMatch, ifModifiedSince, counters)
 			if ifNoneMatch != tt.wantIfNoneMatch {
 				t.Errorf("If-None-Match = %q, want %q", ifNoneMatch, tt.wantIfNoneMatch)
 			}
 			if ifModifiedSince != tt.wantIfModifiedSince {
 				t.Errorf("If-Modified-Since = %q, want %q",
 					ifModifiedSince, tt.wantIfModifiedSince)
 			}
 			if !bytes.Equal(first, second) {
 				t.Error("the variant served after the check differs from the cached one")
 			}
 			if counters.upstreamFetchCount != 1 || counters.transformCount != 1 {
 				t.Errorf("upstream downloads = %d, transforms = %d; want 1 and 1",
 					counters.upstreamFetchCount, counters.transformCount)
 			}
 			_, status = getImage(t, svc, variant)
 			if status != CacheHit {
 				t.Errorf("CacheStatus after the check = %q, want %q", status, CacheHit)
 			}
 			if n := upstream.fetches(); n != 2 {
 				t.Errorf("upstream fetches = %d, want 2", n)
 			}
 		})
 	}
 }
 // TestProxy_Get_ChangedSourceAfterTTLReplacesSourceAndVariants caches two
 // variants of one source, changes the image upstream, and sets the source's
 // check time and both variants' file times two days back. Each variant must
 // then be made again from the new image, which is downloaded once.
 func TestProxy_Get_ChangedSourceAfterTTLReplacesSourceAndVariants(t *testing.T) {
 	t.Parallel()
 	svc, fixtures, upstream := setupConditionalUpstreamProxy(t)
 	variants := []*imagerequest.Request{
 		photoVariant(fixtures, 85, imagerequest.FitCover),
 		photoVariant(fixtures, 40, imagerequest.FitCover),
 	}
 	oldImages := make([][]byte, len(variants))
 	for i, variant := range variants {
 		oldImages[i], _ = getImage(t, svc, variant)
 	}
 	newSource := generateTestJPEG(t, 120, 90, color.RGBA{0, 0, 255, 255})
 	upstream.change(newSource, `"v2"`)
 	twoDaysAgo := time.Now().AddDate(0, 0, -2)
 	for _, variant := range variants {
 		setBackSourceAndVariant(t, svc, variant, twoDaysAgo)
 	}
 	for i, variant := range variants {
 		image, _ := getImage(t, svc, variant)
 		if bytes.Equal(image, oldImages[i]) {
 			t.Errorf("variant %d is still made from the old image", i)
 		}
 	}
 	counters := readCounters(t, svc)
 	t.Logf("counters = %+v, upstream fetches = %d", counters, upstream.fetches())
 	if counters.upstreamFetchCount != 2 {
 		t.Errorf("upstream downloads = %d, want 2", counters.upstreamFetchCount)
 	}
 	cached, err := os.ReadFile(sourceFilePath(svc, variants[0].Source.Key()))
 	if err != nil {
 		t.Fatalf("reading the cached source: %v", err)
 	}
 	if !bytes.Equal(cached, newSource) {
 		t.Error("the cached source is not the new image")
 	}
 }
 // TestProxy_Get_UpstreamFailureAfterTTLServesCachedImage caches a variant,
 // sets its source's check time and the variant's file time two days back, and
 // makes upstream fail. The cached variant must still be served, and a variant
 // not yet cached must be made from the cached source.
 func TestProxy_Get_UpstreamFailureAfterTTLServesCachedImage(t *testing.T) {
 	t.Parallel()
 	for _, failure := range upstreamFailures() {
 		t.Run(failure.name, func(t *testing.T) {
 			t.Parallel()
 			svc, fixtures, upstream := setupConditionalUpstreamProxy(t)
 			variant := photoVariant(fixtures, 85, imagerequest.FitCover)
 			first, _ := getImage(t, svc, variant)
 			setBackSourceAndVariant(t, svc, variant, time.Now().AddDate(0, 0, -2))
 			upstream.fail(failure.err)
 			second, _ := getImage(t, svc, variant)
 			t.Logf("upstream fetches = %d", upstream.fetches())
 			if upstream.fetches() != 2 {
 				t.Errorf("upstream fetches = %d, want 2", upstream.fetches())
 			}
 			if !bytes.Equal(first, second) {
 				t.Error("the variant served while upstream fails differs from the cached one")
 			}
 			getImage(t, svc, photoVariant(fixtures, 40, imagerequest.FitCover))
 		})
 	}
 }
 // TestProxy_Get_FailingUpstreamIsAskedOnceWhileImageIsServedOften caches a
 // variant, sets its source's check time and the variant's file time two days
 // back, and makes every fetch time out. Serving the variant ten times, and a
 // variant not yet cached, must ask upstream once: the failed check puts the
 // source URL in the negative cache.
 func TestProxy_Get_FailingUpstreamIsAskedOnceWhileImageIsServedOften(t *testing.T) {
 	t.Parallel()
 	svc, fixtures, upstream := setupConditionalUpstreamProxy(t)
 	variant := photoVariant(fixtures, 85, imagerequest.FitCover)
 	getImage(t, svc, variant)
 	setBackSourceAndVariant(t, svc, variant, time.Now().AddDate(0, 0, -2))
 	upstream.fail(httpfetcher.ErrUpstreamTimeout)
 	for range 10 {
 		getImage(t, svc, variant)
 	}
 	getImage(t, svc, photoVariant(fixtures, 40, imagerequest.FitCover))
 	t.Logf("upstream fetches = %d", upstream.fetches())
 	if n := upstream.fetches(); n != 2 {
 		t.Errorf("upstream fetches = %d, want 2: the first fetch and one check", n)
 	}
 }
 // TestProxy_Get_UpstreamFailureAfterTTLServesVariantOfEvictedSource caches a
 // variant, sets its file time two days back, removes its source's row and
 // file, as eviction does, and makes upstream fail. The cached variant must
 // still be served.
 func TestProxy_Get_UpstreamFailureAfterTTLServesVariantOfEvictedSource(t *testing.T) {
 	t.Parallel()
 	for _, failure := range upstreamFailures() {
 		t.Run(failure.name, func(t *testing.T) {
 			t.Parallel()
 			svc, fixtures, upstream := setupConditionalUpstreamProxy(t)
 			variant := photoVariant(fixtures, 85, imagerequest.FitCover)
 			first, _ := getImage(t, svc, variant)
 			setBackSourceAndVariant(t, svc, variant, time.Now().AddDate(0, 0, -2))
 			evictSource(t, svc, variant.Source)
 			upstream.fail(failure.err)
 			second, _ := getImage(t, svc, variant)
 			t.Logf("upstream fetches = %d", upstream.fetches())
 			if !bytes.Equal(first, second) {
 				t.Error("the variant served while upstream fails differs from the cached one")
 			}
 			if n := upstream.fetches(); n != 2 {
 				t.Errorf("upstream fetches = %d, want 2", n)
 			}
 		})
 	}
 }
 // TestProxy_Get_FailingUpstreamIsAskedOnceForVariantOfEvictedSource caches a
 // variant, sets its file time two days back, removes its source's row and
 // file, as eviction does, and makes every fetch time out. Serving the variant
 // ten times must ask upstream once: the failed check puts the source URL in
 // the negative cache.
 func TestProxy_Get_FailingUpstreamIsAskedOnceForVariantOfEvictedSource(t *testing.T) {
 	t.Parallel()
 	svc, fixtures, upstream := setupConditionalUpstreamProxy(t)
 	variant := photoVariant(fixtures, 85, imagerequest.FitCover)
 	first, _ := getImage(t, svc, variant)
 	setBackSourceAndVariant(t, svc, variant, time.Now().AddDate(0, 0, -2))
 	evictSource(t, svc, variant.Source)
 	upstream.fail(httpfetcher.ErrUpstreamTimeout)
 	for range 10 {
 		image, _ := getImage(t, svc, variant)
 		if !bytes.Equal(image, first) {
 			t.Fatal("the variant served while upstream fails differs from the cached one")
 		}
 	}
 	t.Logf("upstream fetches = %d", upstream.fetches())
 	if n := upstream.fetches(); n != 2 {
 		t.Errorf("upstream fetches = %d, want 2: the first fetch and one check", n)
 	}
 }
 // evictSource removes the row and then the file of src's cached source, as
 // the cache's eviction does, and leaves its variants cached.
 func evictSource(t *testing.T, svc *testProxy, src imagerequest.Source) {
 	t.Helper()
 	_, err := svc.db.ExecContext(t.Context(),
 		`DELETE FROM source_content WHERE source_key = ?`, string(src.Key()))
 	if err != nil {
 		t.Fatalf("deleting the source's row: %v", err)
 	}
 	err = os.Remove(sourceFilePath(svc, src.Key()))
 	if err != nil {
 		t.Fatalf("removing the source's file: %v", err)
 	}
 }
 // setBackSourceAndVariant sets back to when the times the cache keeps for
 // req's source and for the variant req asks for: the source's fetch and check
 // times, both last access times, the variant's check time, and the variant
 // file's modification time.
 func setBackSourceAndVariant(
 	t *testing.T, svc *testProxy, req *imagerequest.Request, when time.Time,
 ) {
 	t.Helper()
 	key := req.Source.Key()
 	setSourceLastAccessed(t, svc.db, key, when)
 	_, err := svc.db.ExecContext(t.Context(),
 		`UPDATE source_content SET fetched_at = ?, checked_at = ?
 		WHERE source_key = ?`, when.UTC(), when.UTC(), string(key))
 	if err != nil {
 		t.Fatalf("setting back the source's fetch and check times: %v", err)
 	}
 	variantKey := imagerequest.CacheKey(req)
 	setVariantLastAccessed(t, svc.db, variantKey, when)
 	_, err = svc.db.ExecContext(t.Context(),
 		`UPDATE variant_content SET checked_at = ? WHERE cache_key = ?`,
 		when.UTC(), string(variantKey))
 	if err != nil {
 		t.Fatalf("setting back the variant's check time: %v", err)
 	}
 	path := variantFilePath(svc, variantKey)
 	err = os.Chtimes(path, when, when)
 	if err != nil {
 		t.Fatalf("setting back the times of %s: %v", path, err)
 	}
 }
@@ -1,77 +0,0 @@
 package imageproxy
 import (
 	"errors"
 	"testing"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/testutil"
 	"sneak.berlin/go/pixa/internal/imgcache"
 )
 // TestNew_RegistersItsCountersOnItsRegistry checks that New registers the
 // proxy's counters on the registry it is given, under the names README.md
 // gives them. The cache registers its own counters on another registry.
 func TestNew_RegistersItsCountersOnItsRegistry(t *testing.T) {
 	t.Parallel()
 	cache, err := imgcache.NewCache(setupTestDB(t),
 		imgcache.Config{StateDir: t.TempDir(), MaxBytes: 1 << 30},
 		prometheus.NewRegistry())
 	if err != nil {
 		t.Fatalf("imgcache.NewCache() error = %v", err)
 	}
 	registry := prometheus.NewRegistry()
 	_, err = New(&Config{Cache: cache}, registry)
 	if err != nil {
 		t.Fatalf("New() error = %v", err)
 	}
 	names := []string{
 		"pixa_upstream_fetches_total",
 		"pixa_upstream_fetch_bytes_total",
 		"pixa_transforms_total",
 	}
 	count, err := testutil.GatherAndCount(registry, names...)
 	if err != nil {
 		t.Fatalf("testutil.GatherAndCount() error = %v", err)
 	}
 	if count != len(names) {
 		t.Errorf("%d of the counters %v are on the registry, want %d",
 			count, names, len(names))
 	}
 }
 // TestNew_FailsWhenItsCountersCannotBeRegistered makes a second proxy on
 // the registry of a first. Its counters have the same names, so the
 // registry refuses them, and New must return that error.
 func TestNew_FailsWhenItsCountersCannotBeRegistered(t *testing.T) {
 	t.Parallel()
 	cache, err := imgcache.NewCache(setupTestDB(t),
 		imgcache.Config{StateDir: t.TempDir(), MaxBytes: 1 << 30},
 		prometheus.NewRegistry())
 	if err != nil {
 		t.Fatalf("imgcache.NewCache() error = %v", err)
 	}
 	registry := prometheus.NewRegistry()
 	_, err = New(&Config{Cache: cache}, registry)
 	if err != nil {
 		t.Fatalf("New() of the first proxy error = %v", err)
 	}
 	_, err = New(&Config{Cache: cache}, registry)
 	t.Logf("New() of the second proxy error = %v", err)
 	var alreadyRegistered prometheus.AlreadyRegisteredError
 	if !errors.As(err, &alreadyRegistered) {
 		t.Errorf("New() of the second proxy error = %v, want %T",
 			err, alreadyRegistered)
 	}
 }
@@ -1,933 +0,0 @@
 // Package imageproxy fetches, transforms, caches and serves images. Its
 // Proxy serves an image from the cache when it can, and otherwise makes it
 // from the cached or fetched source image.
 package imageproxy
 import (
 	"bytes"
 	"context"
 	"errors"
 	"fmt"
 	"io"
 	"log/slog"
 	"net/http"
 	"runtime/debug"
 	"time"
 	"github.com/dustin/go-humanize"
 	"github.com/getsentry/sentry-go"
 	"github.com/go-chi/chi/v5/middleware"
 	"github.com/prometheus/client_golang/prometheus"
 	"golang.org/x/sync/singleflight"
 	"sneak.berlin/go/pixa/internal/httpfetcher"
 	"sneak.berlin/go/pixa/internal/imageprocessor"
 	"sneak.berlin/go/pixa/internal/imagerequest"
 	"sneak.berlin/go/pixa/internal/imgcache"
 	"sneak.berlin/go/pixa/internal/magic"
 )
 // Proxy orchestrates the cache, fetcher, and processor.
 type Proxy struct {
 	cache           *imgcache.Cache
 	fetcher         httpfetcher.Fetcher
 	processor       *imageprocessor.ImageProcessor
 	log             *slog.Logger
 	maxResponseSize int64
 	// variantsInProgress lets the requests that miss the same variant at the
 	// same time share one fetch and one transcode.
 	variantsInProgress singleflight.Group
 	// The metrics of upstream fetches and transforms, made and registered by
 	// New. They are kept in memory, so updating one waits for nothing.
 	upstreamFetches        prometheus.Counter
 	upstreamFetchBytes     prometheus.Counter
 	upstreamFetchDurations prometheus.Histogram
 	upstreamFetchErrors    prometheus.Counter
 	transforms             prometheus.Counter
 	transformDurations     prometheus.Histogram
 	transformsInProgress   prometheus.Gauge
 }
 // Config holds the proxy's configuration.
 type Config struct {
 	// Cache is the cache instance
 	Cache *imgcache.Cache
 	// Fetcher fetches source images from upstream hosts
 	Fetcher httpfetcher.Fetcher
 	// Processor converts and resizes the images
 	Processor *imageprocessor.ImageProcessor
 	// MaxResponseSize is the largest source accepted, in bytes; a cached
 	// source larger than this is fetched again
 	MaxResponseSize int64
 	// Logger for logging
 	Logger *slog.Logger
 }
 // errCacheRequired is returned when the proxy is built without a cache.
 var errCacheRequired = errors.New("cache is required")
 // New creates a new image proxy and registers its metrics on
 // metricsRegistry. pixad passes Prometheus' default registry, the one
 // /metrics serves. It fails when metricsRegistry already holds metrics of
 // the same names.
 func New(
 	cfg *Config, metricsRegistry prometheus.Registerer,
 ) (*Proxy, error) {
 	if cfg.Cache == nil {
 		return nil, errCacheRequired
 	}
 	log := cfg.Logger
 	if log == nil {
 		log = slog.Default()
 	}
 	// JPEG XL is the default output format, so pixad does not start
 	// without it.
 	err := imageprocessor.CheckJPEGXLSupport()
 	if err != nil {
 		return nil, err
 	}
 	p := &Proxy{
 		cache:           cfg.Cache,
 		fetcher:         cfg.Fetcher,
 		processor:       cfg.Processor,
 		log:             log,
 		maxResponseSize: cfg.MaxResponseSize,
 		upstreamFetches: prometheus.NewCounter(prometheus.CounterOpts{
 			Name: "pixa_upstream_fetches_total",
 			Help: "Fetches of a source image from upstream that read any bytes.",
 		}),
 		upstreamFetchBytes: prometheus.NewCounter(prometheus.CounterOpts{
 			Name: "pixa_upstream_fetch_bytes_total",
 			Help: "Bytes read from upstream by fetches of source images.",
 		}),
 		upstreamFetchDurations: prometheus.NewHistogram(prometheus.HistogramOpts{
 			Name: "pixa_upstream_fetch_duration_seconds",
 			Help: "Duration of the fetches pixa_upstream_fetches_total counts, " +
 				"until the response's last byte.",
 		}),
 		upstreamFetchErrors: prometheus.NewCounter(prometheus.CounterOpts{
 			Name: "pixa_upstream_fetch_errors_total",
 			Help: "Fetches of a source image from upstream that failed, " +
 				"before or while reading the response.",
 		}),
 		transforms: prometheus.NewCounter(prometheus.CounterOpts{
 			Name: "pixa_transforms_total",
 			Help: "Images the image processor transformed.",
 		}),
 		transformDurations: prometheus.NewHistogram(prometheus.HistogramOpts{
 			Name: "pixa_transform_duration_seconds",
 			Help: "Duration of the transforms pixa_transforms_total counts, " +
 				"waiting for a processing slot included.",
 		}),
 		transformsInProgress: prometheus.NewGauge(prometheus.GaugeOpts{
 			Name: "pixa_transforms_in_progress",
 			Help: "Images being transformed or waiting for a processing slot.",
 		}),
 	}
 	for _, metric := range []prometheus.Collector{
 		p.upstreamFetches, p.upstreamFetchBytes, p.upstreamFetchDurations,
 		p.upstreamFetchErrors, p.transforms, p.transformDurations,
 		p.transformsInProgress,
 	} {
 		err = metricsRegistry.Register(metric)
 		if err != nil {
 			return nil, fmt.Errorf("failed to register the proxy's metrics: %w", err)
 		}
 	}
 	return p, nil
 }
 // ErrNegativeCached is returned when a URL is in the negative cache (recently failed).
 var ErrNegativeCached = errors.New("request is in negative cache (recently failed)")
 // ErrProcessingTimedOut is returned when processing an image stopped because
 // the downstream_timeout of the request doing it ended, to that request and to
 // every request that waited for its image.
 var ErrProcessingTimedOut = errors.New(
 	"image processing stopped at the deadline of the request doing it")
 // ImageResponse represents a processed image ready to serve
 type ImageResponse struct {
 	// Content is the image data reader
 	Content io.ReadCloser
 	// ContentLength is the size in bytes (-1 if unknown)
 	ContentLength int64
 	// ContentType is the MIME type of the response
 	ContentType string
 	// ETag is the entity tag for caching
 	ETag string
 	// CacheStatus indicates HIT or MISS
 	CacheStatus CacheStatus
 	// FetchedBytes is the number of bytes fetched from upstream (0 if cache hit)
 	FetchedBytes int64
 }
 // CacheStatus indicates whether the response was served from cache.
 type CacheStatus string
 // Cache status values for response headers.
 const (
 	CacheHit  CacheStatus = "HIT"
 	CacheMiss CacheStatus = "MISS"
 )
 // Get retrieves a processed image, fetching and processing if necessary.
 // While its source URL is in the negative cache, a cached variant is still
 // served and a variant not in the cache is still made from a cached source;
 // only a request that needs the source fetched is refused.
 //
 // A cache hit opens the variant file and makes no database call: the cache
 // hands its access time to the goroutine that writes access times, without
 // waiting for it, and its hit is counted in memory. A variant whose source
 // was last checked with upstream CacheTTL or more ago is a miss, which checks
 // the source first (see processFromSourceOrFetch). A variant file that
 // cannot be served, such as one whose first bytes are not those of an output
 // format, is a miss, and the variant is made again.
 func (p *Proxy) Get(
 	ctx context.Context, req *imagerequest.Request,
 ) (*ImageResponse, error) {
 	cacheKey := imagerequest.CacheKey(req)
 	cached, err := p.cache.Variant(cacheKey)
 	if err == nil {
 		p.cache.IncrementStats(true)
 		return &ImageResponse{
 			Content:       cached.Content,
 			ContentLength: cached.Size,
 			ContentType:   cached.ContentType,
 			CacheStatus:   CacheHit,
 			ETag:          formatETag(cacheKey, cached.CheckedAt),
 		}, nil
 	}
 	if !errors.Is(err, imgcache.ErrNotFound) && !errors.Is(err, imgcache.ErrStale) {
 		p.log.Warn("cached variant not served, making it again",
 			"cache_key", cacheKey, "error", err)
 	}
 	// Cache miss - get the variant, processed once for all the requests that
 	// miss it at the same time, then count this request's miss, also when it
 	// failed or the request context has ended meanwhile
 	response, err := p.processOrWait(ctx, req)
 	p.cache.IncrementStats(false)
 	if err != nil {
 		return nil, err
 	}
 	response.CacheStatus = CacheMiss
 	return response, nil
 }
 // WaitForProcessing waits until no image is being processed, or until ctx
 // ends, and returns how many images were still being processed then.
 func (p *Proxy) WaitForProcessing(ctx context.Context) int {
 	return p.processor.WaitForProcessing(ctx)
 }
 // errPanicked is returned when processing a variant panicked.
 var errPanicked = errors.New("panic while processing image")
 // processOrWait returns the variant req asks for. The first of the requests
 // that miss a variant at the same time processes it, and singleflight hands
 // its result, or its error, to the others: they fetch nothing, read no source
 // and take no upstream connection or processing slot. The processing ignores
 // the first request's cancellation, so the others are still served if that
 // client goes away, but keeps its deadline.
 func (p *Proxy) processOrWait(
 	ctx context.Context, req *imagerequest.Request,
 ) (*ImageResponse, error) {
 	// A request that has already ended starts no processing
 	if ctx.Err() != nil {
 		return nil, ctx.Err()
 	}
 	cacheKey := imagerequest.CacheKey(req)
 	// Closed when this request's own function runs, which singleflight does
 	// only when no other request is processing the variant
 	processing := make(chan struct{})
 	results := p.variantsInProgress.DoChan(string(cacheKey),
 		func() (_ any, err error) {
 			close(processing)
 			// singleflight would raise a panic again in a goroutine of its
 			// own, where no handler recovers it, and stop pixad. It is
 			// reported through the Sentry hub that the Sentry middleware puts
 			// on the request's context when sentry_dsn is set.
 			defer func() {
 				recovered := recover()
 				if recovered != nil {
 					p.log.Error("panic while processing image",
 						"host", req.Source.Host, "path", req.Source.Path,
 						"panic", recovered, "stack", string(debug.Stack()))
 					if hub := sentry.GetHubFromContext(ctx); hub != nil {
 						hub.RecoverWithContext(ctx, recovered)
 					}
 					err = fmt.Errorf("%w: %v", errPanicked, recovered)
 				}
 			}()
 			processingCtx, cancel := withoutCancelKeepingDeadline(ctx)
 			defer cancel()
 			return p.processFromSourceOrFetch(processingCtx, req, cacheKey)
 		})
 	var result singleflight.Result
 	select {
 	case result = <-results:
 	case <-ctx.Done():
 		select {
 		case <-processing:
 			// This request is processing the variant: it waits for the
 			// result, as every request did before misses were shared
 			result = <-results
 		default:
 			// Another request is processing the variant, or this request's
 			// function has not started yet; the processing goes on without it
 			return nil, ctx.Err()
 		}
 	}
 	if result.Err != nil {
 		return nil, result.Err
 	}
 	variant, _ := result.Val.(*processedVariant)
 	return &ImageResponse{
 		Content:       io.NopCloser(bytes.NewReader(variant.data)),
 		ContentLength: int64(len(variant.data)),
 		ContentType:   variant.contentType,
 		FetchedBytes:  variant.fetchedBytes,
 		ETag:          formatETag(cacheKey, variant.checkedAt),
 	}, nil
 }
 // withoutCancelKeepingDeadline returns ctx without its cancellation but with
 // its deadline, if it has one, and the func that releases the returned
 // context.
 func withoutCancelKeepingDeadline(
 	ctx context.Context,
 ) (context.Context, context.CancelFunc) {
 	deadline, hasDeadline := ctx.Deadline()
 	if !hasDeadline {
 		return context.WithoutCancel(ctx), func() {}
 	}
 	return context.WithDeadline(context.WithoutCancel(ctx), deadline)
 }
 // loadCachedSource opens src's cached source, reading only the first bytes,
 // which give its format, and returns it with its size and its format. It
 // returns nil if the source is not in the cache, cannot be read, is in no
 // source format or exceeds maxResponseSize.
 func (p *Proxy) loadCachedSource(
 	ctx context.Context, src imagerequest.Source,
 ) (io.ReadCloser, int64, imagerequest.Format) {
 	reader, size, format, err := p.cache.Source(ctx, src)
 	if errors.Is(err, imgcache.ErrNotFound) {
 		return nil, 0, ""
 	}
 	if err != nil {
 		p.log.Warn("failed to load cached source, fetching", "error", err)
 		return nil, 0, ""
 	}
 	p.log.Debug("using cached source", "source_key", src.Key())
 	if size > p.maxResponseSize {
 		_ = reader.Close()
 		p.log.Warn("cached source exceeds max response size, discarding",
 			"source_key", src.Key(),
 			"max_bytes", p.maxResponseSize,
 		)
 		return nil, 0, ""
 	}
 	return reader, size, format
 }
 // processFromSourceOrFetch makes the variant req asks for, from the cached
 // source when there is one and from a fetched source otherwise. It counts a
 // source cache miss when it fetches the source because the source has no row
 // in the cache or its cached file cannot be used, and a source cache hit
 // otherwise.
 //
 // A cached source last checked with upstream CacheTTL or more ago is checked
 // first: upstream is asked to send it only if it changed since. When it
 // changed, the new bytes replace the cached source and the variant is made
 // from them. When it did not change, or the check fails, the cached source
 // is used: the variant's cached file is served again if it was made from the
 // cached source's bytes, and otherwise the variant is made from them. When
 // the source is not cached but the variant is, the variant is checked with
 // upstream the same way (see fetchAndProcess).
 func (p *Proxy) processFromSourceOrFetch(
 	ctx context.Context,
 	req *imagerequest.Request,
 	cacheKey imagerequest.VariantKey,
 ) (*processedVariant, error) {
 	cached, err := p.cache.LookupSource(ctx, req.Source)
 	if err != nil {
 		if !errors.Is(err, imgcache.ErrNotFound) {
 			p.log.Warn("failed to look up cached source, fetching", "error", err)
 		}
 		p.cache.IncrementSourceStats(false)
 		return p.fetchAndProcess(ctx, req, cacheKey)
 	}
 	if p.cache.Stale(cached.CheckedAt) {
 		fetched, err := p.fetchSource(ctx, req, cached.ETag, cached.LastModified)
 		switch {
 		case errors.Is(err, errSourceNotModified):
 			cached.CheckedAt = time.Now().UTC()
 			p.renewSource(ctx, req.Source, cached.CheckedAt)
 		case err != nil:
 			p.recordFailedCheck(ctx, req, err)
 		default:
 			p.cache.IncrementSourceStats(true)
 			return p.processFetched(ctx, req, cacheKey, fetched)
 		}
 	}
 	variant := p.renewVariant(ctx, cacheKey, cached)
 	if variant != nil {
 		p.cache.IncrementSourceStats(true)
 		return variant, nil
 	}
 	source, sourceSize, sourceFormat := p.loadCachedSource(ctx, req.Source)
 	p.cache.IncrementSourceStats(source != nil)
 	// Fetch from upstream if we don't have source data or it's empty
 	if source == nil {
 		return p.fetchAndProcess(ctx, req, cacheKey)
 	}
 	defer func() { _ = source.Close() }()
 	// Process using cached source; nothing was fetched from upstream. The
 	// image processor reads the source only once it has a processing slot,
 	// so a request waiting for one holds none of it in memory.
 	return p.processAndStore(ctx, req, cacheKey, cached, source, sourceFormat,
 		sourceSize)
 }
 // recordFailedCheck logs a failed check of req's source with upstream, after
 // which the image is still served from the cache. It puts the source URL in
 // the negative cache, whatever the failure, a timeout included, so upstream
 // is asked at most once per NegativeTTL while it fails, however often the
 // image is served. A failure that was a negative cache hit records nothing.
 func (p *Proxy) recordFailedCheck(
 	ctx context.Context, req *imagerequest.Request, err error,
 ) {
 	if errors.Is(err, ErrNegativeCached) {
 		return
 	}
 	p.log.Warn("checking source with upstream failed, serving from the cache",
 		"request_id", middleware.GetReqID(ctx),
 		"host", req.Source.Host, "path", req.Source.Path, "error", err)
 	p.storeNegative(ctx, req)
 }
 // renewSource records that upstream answered at checkedAt that src's cached
 // source had not changed. A failure to record it is only logged: the source
 // is then checked again on its next use.
 func (p *Proxy) renewSource(
 	ctx context.Context, src imagerequest.Source, checkedAt time.Time,
 ) {
 	err := p.cache.RenewSource(ctx, src, checkedAt)
 	if err != nil {
 		p.log.Warn("failed to renew cached source", "source_key", src.Key(),
 			"error", err)
 	}
 }
 // renewVariant returns the cached variant of cacheKey when it was made from
 // the bytes of the cached source that source describes, and renews it to
 // source.CheckedAt (see imgcache.Cache.RenewVariant). It returns nil when
 // there is no such variant or it cannot be read.
 func (p *Proxy) renewVariant(
 	ctx context.Context, cacheKey imagerequest.VariantKey,
 	source imgcache.SourceInfo,
 ) *processedVariant {
 	cached, err := p.cache.RenewVariant(ctx, cacheKey, source)
 	if err != nil {
 		if !errors.Is(err, imgcache.ErrNotFound) {
 			p.log.Warn("cached variant not renewed, making it again",
 				"cache_key", cacheKey, "error", err)
 		}
 		return nil
 	}
 	return p.readCachedVariant(cacheKey, cached)
 }
 // cachedVariantIgnoringTTL returns the cached variant of cacheKey whatever
 // its age, with what its row keeps about the source bytes it was made from
 // (see imgcache.Cache.LookupVariant). It returns nil when the variant is not
 // cached or cannot be read. The SourceInfo is empty when the variant is not
 // returned, or its row is missing or cannot be read.
 func (p *Proxy) cachedVariantIgnoringTTL(
 	ctx context.Context, cacheKey imagerequest.VariantKey,
 ) (*processedVariant, imgcache.SourceInfo) {
 	cached, err := p.cache.VariantIgnoringTTL(cacheKey)
 	if err != nil {
 		if !errors.Is(err, imgcache.ErrNotFound) {
 			p.log.Warn("cached variant not served", "cache_key", cacheKey,
 				"error", err)
 		}
 		return nil, imgcache.SourceInfo{}
 	}
 	variant := p.readCachedVariant(cacheKey, cached)
 	if variant == nil {
 		return nil, imgcache.SourceInfo{}
 	}
 	madeFrom, err := p.cache.LookupVariant(ctx, cacheKey)
 	if err != nil && !errors.Is(err, imgcache.ErrNotFound) {
 		p.log.Warn("failed to look up cached variant", "cache_key", cacheKey,
 			"error", err)
 	}
 	return variant, madeFrom
 }
 // readCachedVariant reads the cached variant of cacheKey from its opened file,
 // and closes the file. It returns nil when the variant cannot be read.
 func (p *Proxy) readCachedVariant(
 	cacheKey imagerequest.VariantKey, file imgcache.VariantFile,
 ) *processedVariant {
 	defer func() { _ = file.Content.Close() }()
 	data, err := io.ReadAll(file.Content)
 	if err != nil {
 		p.log.Warn("failed to read cached variant", "cache_key", cacheKey,
 			"error", err)
 		return nil
 	}
 	return &processedVariant{
 		data:        data,
 		contentType: file.ContentType,
 		checkedAt:   file.CheckedAt,
 	}
 }
 // fetchAndProcess fetches the source from upstream, stores it, and makes
 // and stores the variant from it.
 //
 // The variant can still be cached after eviction removed its source. The
 // fetch then sends the ETag and Last-Modified of the source bytes the variant
 // was made from, so upstream sends the source only if it changed since. When
 // it did not change, the cached variant is renewed and served, with no
 // download and no conversion. When the fetch fails, the cached variant is
 // served whatever its age, and the failure is recorded as a failed check (see
 // recordFailedCheck).
 func (p *Proxy) fetchAndProcess(
 	ctx context.Context,
 	req *imagerequest.Request,
 	cacheKey imagerequest.VariantKey,
 ) (*processedVariant, error) {
 	variant, madeFrom := p.cachedVariantIgnoringTTL(ctx, cacheKey)
 	fetched, err := p.fetchSource(ctx, req, madeFrom.ETag, madeFrom.LastModified)
 	switch {
 	case err == nil:
 		return p.processFetched(ctx, req, cacheKey, fetched)
 	case variant == nil:
 		return nil, err
 	case errors.Is(err, errSourceNotModified):
 		variant.checkedAt = time.Now().UTC()
 		err = p.cache.SetVariantCheckedAt(ctx, cacheKey, variant.checkedAt)
 		if err != nil {
 			p.log.Warn("failed to renew cached variant", "cache_key", cacheKey,
 				"error", err)
 		}
 	default:
 		p.recordFailedCheck(ctx, req, err)
 	}
 	return variant, nil
 }
 // processFetched makes and stores the variant from the source fetchSource
 // fetched, then closes the fetch's response.
 func (p *Proxy) processFetched(
 	ctx context.Context,
 	req *imagerequest.Request,
 	cacheKey imagerequest.VariantKey,
 	fetched *fetchedSource,
 ) (*processedVariant, error) {
 	// Closing the response frees the upstream connection. It is closed only
 	// after processing, so the fetcher's connection limit also bounds the
 	// fetched sources held in memory while their requests wait for a
 	// processing slot.
 	defer func() { _ = fetched.response.Close() }()
 	return p.processAndStore(ctx, req, cacheKey, fetched.info,
 		bytes.NewReader(fetched.data), fetched.format, int64(len(fetched.data)))
 }
 // errSourceNotModified is returned by fetchSource when upstream answers 304
 // Not Modified: the cached source has not changed.
 var errSourceNotModified = errors.New("upstream source not modified")
 // fetchedSource is a source fetchSource fetched and stored in the cache.
 type fetchedSource struct {
 	data   []byte
 	format imagerequest.Format
 	// info is what the cache keeps about the source
 	info imgcache.SourceInfo
 	// response is the fetch's response, still open; closing it frees the
 	// upstream connection
 	response io.Closer
 }
 // fetchSource fetches req's source from upstream and stores it in the cache.
 // A non-empty ifNoneMatch or ifModifiedSince asks upstream to send the source
 // only if it changed since; errSourceNotModified says it did not. It counts
 // the fetch with the bytes read from upstream and its duration, including
 // when reading the response or a later step fails, and counts a fetch that
 // fails or whose response cannot be read as an upstream fetch error. It
 // fetches nothing while the source URL is in the negative cache. The caller
 // closes the returned response.
 func (p *Proxy) fetchSource(
 	ctx context.Context,
 	req *imagerequest.Request,
 	ifNoneMatch, ifModifiedSince string,
 ) (*fetchedSource, error) {
 	err := p.refuseNegativeCached(ctx, req)
 	if err != nil {
 		return nil, err
 	}
 	// Fetch from upstream
 	p.log.Debug("fetching from upstream", "host", req.Source.Host,
 		"path", req.Source.Path, "query", req.Source.Query)
 	fetchStart := time.Now()
 	fetchResult, err := p.fetcher.Fetch(ctx, req.Source,
 		ifNoneMatch, ifModifiedSince)
 	if err != nil {
 		p.upstreamFetchErrors.Inc()
 		// Store negative cache for certain errors
 		if isNegativeCacheable(err) {
 			p.storeNegative(ctx, req)
 		}
 		return nil, fmt.Errorf("upstream fetch failed: %w", err)
 	}
 	if fetchResult.StatusCode == http.StatusNotModified {
 		_ = fetchResult.Content.Close()
 		p.log.Info("upstream source not modified",
 			"request_id", middleware.GetReqID(ctx), "host", req.Source.Host,
 			"path", req.Source.Path, "fetch_ms", fetchResult.FetchDurationMs)
 		return nil, errSourceNotModified
 	}
 	// Read and validate the source content
 	sourceData, err := io.ReadAll(fetchResult.Content)
 	fetchBytes := int64(len(sourceData))
 	// Counted also when the request context has ended meanwhile
 	p.incrementUpstreamFetch(fetchBytes, time.Since(fetchStart))
 	if err != nil {
 		p.upstreamFetchErrors.Inc()
 		_ = fetchResult.Content.Close()
 		return nil, fmt.Errorf("failed to read upstream response: %w", err)
 	}
 	p.logUpstreamFetch(ctx, req, fetchResult, fetchBytes)
 	// The source's format, detected from its first bytes, which must match
 	// its content type. A body that does not is the upstream's error, so it
 	// gets a negative cache entry, as an upstream error status does.
 	sourceFormat, err := magic.ValidateMagicBytes(sourceData,
 		fetchResult.ContentType)
 	if err != nil {
 		p.log.Warn("source refused", "request_id", middleware.GetReqID(ctx),
 			"host", req.Source.Host, "path", req.Source.Path,
 			"content_type", fetchResult.ContentType, "error", err)
 		p.storeNegative(ctx, req)
 		_ = fetchResult.Content.Close()
 		return nil, fmt.Errorf("content validation failed: %w", err)
 	}
 	info := fetchedSourceInfo(fetchResult)
 	// Store source content
 	_, err = p.cache.PutSource(ctx, req.Source, bytes.NewReader(sourceData), info)
 	if err != nil {
 		p.log.Warn("failed to store source content", "error", err)
 		// Continue even if caching fails
 	}
 	return &fetchedSource{
 		data:     sourceData,
 		format:   sourceFormat,
 		info:     info,
 		response: fetchResult.Content,
 	}, nil
 }
 // refuseNegativeCached returns an error wrapping ErrNegativeCached while
 // req's source URL is in the negative cache, and nil otherwise. A failure to
 // read the negative cache is only logged, and returns nil.
 func (p *Proxy) refuseNegativeCached(
 	ctx context.Context, req *imagerequest.Request,
 ) error {
 	negHit, err := p.cache.Failure(ctx, req.Source)
 	if err != nil {
 		p.log.Warn("negative cache check failed", "error", err)
 	}
 	if !negHit {
 		return nil
 	}
 	p.log.Debug("negative cache hit",
 		"host", req.Source.Host,
 		"path", req.Source.Path,
 	)
 	return fmt.Errorf("%w: %w", httpfetcher.ErrUpstreamError, ErrNegativeCached)
 }
 // fetchedSourceInfo returns what the cache keeps about a source upstream
 // just sent: fetched and checked now, with the ETag and Last-Modified
 // headers of fetchResult.
 func fetchedSourceInfo(fetchResult *httpfetcher.FetchResult) imgcache.SourceInfo {
 	now := time.Now().UTC()
 	upstreamHeaders := http.Header(fetchResult.Headers)
 	return imgcache.SourceInfo{
 		FetchedAt:    now,
 		CheckedAt:    now,
 		ETag:         upstreamHeaders.Get("ETag"),
 		LastModified: upstreamHeaders.Get("Last-Modified"),
 	}
 }
 // logUpstreamFetch logs a fetch of req's source that read fetchBytes bytes,
 // with its download rate and connection details.
 func (p *Proxy) logUpstreamFetch(
 	ctx context.Context,
 	req *imagerequest.Request,
 	fetchResult *httpfetcher.FetchResult,
 	fetchBytes int64,
 ) {
 	var downloadRate string
 	if fetchResult.FetchDurationMs > 0 {
 		seconds := float64(fetchResult.FetchDurationMs) / 1000.0 //nolint:mnd // ms to seconds
 		bitsPerSecond := float64(fetchBytes*8) / seconds         //nolint:mnd // bytes to bits
 		downloadRate = humanize.SI(bitsPerSecond, "bps")
 	}
 	p.log.Info("upstream fetched",
 		"request_id", middleware.GetReqID(ctx),
 		"host", req.Source.Host,
 		"path", req.Source.Path,
 		"bytes", fetchBytes,
 		"fetch_ms", fetchResult.FetchDurationMs,
 		"rate", downloadRate,
 		"remote_addr", fetchResult.RemoteAddr,
 		"http", fetchResult.HTTPVersion,
 		"tls", fetchResult.TLSVersion,
 		"cipher", fetchResult.TLSCipherSuite,
 	)
 }
 // incrementUpstreamFetch counts one upstream fetch that read fetchBytes bytes
 // and took duration. A fetch that read no bytes is not counted.
 func (p *Proxy) incrementUpstreamFetch(fetchBytes int64, duration time.Duration) {
 	if fetchBytes <= 0 {
 		return
 	}
 	p.upstreamFetches.Inc()
 	p.upstreamFetchBytes.Add(float64(fetchBytes))
 	p.upstreamFetchDurations.Observe(duration.Seconds())
 }
 // storeNegative stores a negative cache entry for req's source, whose fetch
 // failed, so the source is not fetched again until the entry expires. A
 // failure to store the entry is only logged.
 func (p *Proxy) storeNegative(ctx context.Context, req *imagerequest.Request) {
 	err := p.cache.PutFailure(ctx, req.Source)
 	if err != nil {
 		p.log.Warn("failed to store negative cache entry",
 			"host", req.Source.Host, "path", req.Source.Path, "error", err)
 	}
 }
 // processedVariant is a variant as processAndStore made it. Each request that
 // shared its processing serves it through a reader of its own.
 type processedVariant struct {
 	data         []byte
 	contentType  string
 	fetchedBytes int64
 	// checkedAt is its source's check time when the variant was made or last
 	// renewed, which its cached file has as its modification time
 	checkedAt time.Time
 }
 // processAndStore processes the image read from source, which is in
 // sourceFormat, and stores the result. sourceInfo describes the source's
 // bytes, and is stored with the variant (see imgcache.Cache.PutVariant).
 func (p *Proxy) processAndStore(
 	ctx context.Context,
 	req *imagerequest.Request,
 	cacheKey imagerequest.VariantKey,
 	sourceInfo imgcache.SourceInfo,
 	source io.Reader,
 	sourceFormat imagerequest.Format,
 	fetchBytes int64,
 ) (*processedVariant, error) {
 	// Process the image
 	processStart := time.Now()
 	// ctx has the deadline of the request doing the processing, which can
 	// end while a request waiting for its image has time left
 	processResult, err := p.transform(ctx, source, sourceFormat, &req.Transform)
 	if errors.Is(err, context.DeadlineExceeded) {
 		return nil, fmt.Errorf("%w: %w", ErrProcessingTimedOut, err)
 	}
 	if err != nil {
 		return nil, fmt.Errorf("image processing failed: %w", err)
 	}
 	processDuration := time.Since(processStart)
 	// Counted also when the request context has ended meanwhile
 	p.transforms.Inc()
 	p.transformDurations.Observe(processDuration.Seconds())
 	// Read processed content
 	processedData, err := io.ReadAll(processResult.Content)
 	_ = processResult.Content.Close()
 	if err != nil {
 		return nil, fmt.Errorf("failed to read processed content: %w", err)
 	}
 	// Log conversion details
 	outputSize := int64(len(processedData))
 	var sizePercent float64
 	if fetchBytes > 0 {
 		//nolint:mnd // percentage calculation
 		sizePercent = float64(outputSize) / float64(fetchBytes) * 100.0
 	}
 	p.log.Info("image converted",
 		"request_id", middleware.GetReqID(ctx),
 		"host", req.Source.Host,
 		"path", req.Source.Path,
 		"src_format", sourceFormat,
 		"dst_format", req.Transform.Format,
 		"src_bytes", fetchBytes,
 		"dst_bytes", outputSize,
 		"src_dimensions", fmt.Sprintf("%dx%d",
 			processResult.InputWidth, processResult.InputHeight),
 		"dst_dimensions", fmt.Sprintf("%dx%d",
 			processResult.Width, processResult.Height),
 		"size_ratio", fmt.Sprintf("%.1f%%", sizePercent),
 		"convert_ms", processDuration.Milliseconds(),
 		"quality", req.Transform.Quality,
 		"fit", req.Transform.FitMode,
 	)
 	// Store variant to cache
 	err = p.cache.PutVariant(ctx, cacheKey, sourceInfo,
 		bytes.NewReader(processedData))
 	if err != nil {
 		p.log.Warn("failed to store variant", "error", err)
 		// Continue even if caching fails
 	}
 	return &processedVariant{
 		data:         processedData,
 		contentType:  processResult.ContentType,
 		fetchedBytes: fetchBytes,
 		checkedAt:    sourceInfo.CheckedAt,
 	}, nil
 }
 // transform has the image processor transform the image read from source
 // as requested says, and counts it in pixa_transforms_in_progress until the
 // processor returns or panics.
 func (p *Proxy) transform(
 	ctx context.Context,
 	source io.Reader,
 	sourceFormat imagerequest.Format,
 	requested *imagerequest.Transform,
 ) (*imageprocessor.Result, error) {
 	p.transformsInProgress.Inc()
 	defer p.transformsInProgress.Dec()
 	return p.processor.Process(ctx, source, sourceFormat, requested)
 }
 // isNegativeCacheable returns true if the error should be cached.
 func isNegativeCacheable(err error) bool {
 	return errors.Is(err, httpfetcher.ErrUpstreamError)
 }
 // etagHashLength is the number of hash characters to use for ETags.
 const etagHashLength = 16
 // formatETag returns the quoted ETag of the variant of key: the first
 // etagHashLength characters of key, then checkedAt in Unix nanoseconds.
 // checkedAt is its source's check time when the variant was made or last
 // renewed, so a variant made again from new source bytes gets another ETag.
 func formatETag(key imagerequest.VariantKey, checkedAt time.Time) string {
 	hash := string(key)
 	// Use first 16 characters of hash for a shorter but still unique ETag
 	if len(hash) > etagHashLength {
 		hash = hash[:etagHashLength]
 	}
 	return fmt.Sprintf(`"%s-%d"`, hash, checkedAt.UnixNano())
 }
@@ -1,482 +0,0 @@
 package imageproxy
 import (
 	"context"
 	"io"
 	"testing"
 	"sneak.berlin/go/pixa/internal/imagerequest"
 	"sneak.berlin/go/pixa/internal/magic"
 )
 // Test data literals used repeatedly in this file (goconst).
 const (
 	testPathPhoto  = "/images/photo.jpg"
 	testPathUpload = "/uploads/image.jpg"
 )
 func TestProxy_Get_GoodHost(t *testing.T) {
 	t.Parallel()
 	svc, fixtures := setupTestProxy(t)
 	ctx := context.Background()
 	req := &imagerequest.Request{
 		Source: imagerequest.Source{
 			Host: fixtures.GoodHost,
 			Path: testPathPhoto,
 		},
 		Transform: imagerequest.Transform{
 			Size:    imagerequest.Size{Width: 50, Height: 50},
 			Format:  imagerequest.FormatJPEG,
 			Quality: 85,
 			FitMode: imagerequest.FitCover,
 		},
 	}
 	resp, err := svc.Get(ctx, req)
 	if err != nil {
 		t.Fatalf("Get() error = %v", err)
 	}
 	defer func() { _ = resp.Content.Close() }()
 	// Verify we got content
 	data, err := io.ReadAll(resp.Content)
 	if err != nil {
 		t.Fatalf("failed to read response: %v", err)
 	}
 	if len(data) == 0 {
 		t.Error("expected non-empty response")
 	}
 	if resp.ContentType != testContentTypeJPEG {
 		t.Errorf("ContentType = %q, want %q", resp.ContentType, testContentTypeJPEG)
 	}
 }
 // TestProxy_Get_OtherHost checks that the proxy serves a second host as it
 // serves GoodHost.
 func TestProxy_Get_OtherHost(t *testing.T) {
 	t.Parallel()
 	svc, fixtures := setupTestProxy(t)
 	ctx := context.Background()
 	req := &imagerequest.Request{
 		Source: imagerequest.Source{
 			Host: fixtures.OtherHost,
 			Path: testPathUpload,
 		},
 		Transform: imagerequest.Transform{
 			Size:    imagerequest.Size{Width: 50, Height: 50},
 			Format:  imagerequest.FormatJPEG,
 			Quality: 85,
 			FitMode: imagerequest.FitCover,
 		},
 	}
 	// Should fetch successfully
 	resp, err := svc.Get(ctx, req)
 	if err != nil {
 		t.Fatalf("Get() error = %v", err)
 	}
 	defer func() { _ = resp.Content.Close() }()
 	data, err := io.ReadAll(resp.Content)
 	if err != nil {
 		t.Fatalf("failed to read response: %v", err)
 	}
 	if len(data) == 0 {
 		t.Error("expected non-empty response")
 	}
 }
 func TestProxy_Get_InvalidFile(t *testing.T) {
 	t.Parallel()
 	svc, fixtures := setupTestProxy(t)
 	ctx := context.Background()
 	req := photoVariant(fixtures, 85, imagerequest.FitCover)
 	req.Source.Path = "/images/fake.jpg"
 	req.Transform.Size = imagerequest.Size{Width: 50, Height: 50}
 	// Should fail because magic bytes don't match
 	_, err := svc.Get(ctx, req)
 	if err == nil {
 		t.Error("Get() expected error for invalid file")
 	}
 }
 func TestProxy_Get_NotFound(t *testing.T) {
 	t.Parallel()
 	svc, fixtures := setupTestProxy(t)
 	ctx := context.Background()
 	req := photoVariant(fixtures, 85, imagerequest.FitCover)
 	req.Source.Path = "/images/nonexistent.jpg"
 	req.Transform.Size = imagerequest.Size{Width: 50, Height: 50}
 	_, err := svc.Get(ctx, req)
 	if err == nil {
 		t.Error("Get() expected error for nonexistent file")
 	}
 }
 func TestProxy_Get_FormatConversion(t *testing.T) {
 	t.Parallel()
 	svc, fixtures := setupTestProxy(t)
 	ctx := context.Background()
 	tests := []struct {
 		name       string
 		sourcePath string
 		outFormat  imagerequest.Format
 		wantMIME   string
 	}{
 		{
 			name:       "JPEG to PNG",
 			sourcePath: testPathPhoto,
 			outFormat:  imagerequest.FormatPNG,
 			wantMIME:   "image/png",
 		},
 		{
 			name:       "PNG to JPEG",
 			sourcePath: "/images/logo.png",
 			outFormat:  imagerequest.FormatJPEG,
 			wantMIME:   testContentTypeJPEG,
 		},
 		{
 			name:       "GIF to PNG",
 			sourcePath: "/images/animation.gif",
 			outFormat:  imagerequest.FormatPNG,
 			wantMIME:   "image/png",
 		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			req := &imagerequest.Request{
 				Source: imagerequest.Source{Host: fixtures.GoodHost, Path: tt.sourcePath},
 				Transform: imagerequest.Transform{
 					Size:   imagerequest.Size{Width: 50, Height: 50},
 					Format: tt.outFormat, Quality: 85, FitMode: imagerequest.FitCover,
 				},
 			}
 			resp, err := svc.Get(ctx, req)
 			if err != nil {
 				t.Fatalf("Get() error = %v", err)
 			}
 			defer func() { _ = resp.Content.Close() }()
 			if resp.ContentType != tt.wantMIME {
 				t.Errorf("ContentType = %q, want %q", resp.ContentType, tt.wantMIME)
 			}
 			// Verify magic bytes match the expected format
 			data, err := io.ReadAll(resp.Content)
 			if err != nil {
 				t.Fatalf("failed to read response: %v", err)
 			}
 			detectedFormat, err := magic.DetectFormat(data)
 			if err != nil {
 				t.Fatalf("failed to detect format: %v", err)
 			}
 			if detectedFormat.MIMEType() != tt.wantMIME {
 				t.Errorf("detected format = %q, want the format of %s",
 					detectedFormat, tt.wantMIME)
 			}
 		})
 	}
 }
 func TestProxy_Get_Caching(t *testing.T) {
 	t.Parallel()
 	svc, fixtures := setupTestProxy(t)
 	ctx := context.Background()
 	req := &imagerequest.Request{
 		Source: imagerequest.Source{
 			Host: fixtures.GoodHost,
 			Path: testPathPhoto,
 		},
 		Transform: imagerequest.Transform{
 			Size:    imagerequest.Size{Width: 50, Height: 50},
 			Format:  imagerequest.FormatJPEG,
 			Quality: 85,
 			FitMode: imagerequest.FitCover,
 		},
 	}
 	// First request - should be a cache miss
 	resp1, err := svc.Get(ctx, req)
 	if err != nil {
 		t.Fatalf("Get() first request error = %v", err)
 	}
 	if resp1.CacheStatus != CacheMiss {
 		t.Errorf("first request CacheStatus = %q, want %q", resp1.CacheStatus, CacheMiss)
 	}
 	data1, err := io.ReadAll(resp1.Content)
 	if err != nil {
 		t.Fatalf("failed to read first response: %v", err)
 	}
 	_ = resp1.Content.Close()
 	// Second request - should be a cache hit
 	resp2, err := svc.Get(ctx, req)
 	if err != nil {
 		t.Fatalf("Get() second request error = %v", err)
 	}
 	if resp2.CacheStatus != CacheHit {
 		t.Errorf("second request CacheStatus = %q, want %q", resp2.CacheStatus, CacheHit)
 	}
 	data2, err := io.ReadAll(resp2.Content)
 	if err != nil {
 		t.Fatalf("failed to read second response: %v", err)
 	}
 	_ = resp2.Content.Close()
 	// Content should be identical
 	if len(data1) != len(data2) {
 		t.Errorf("response sizes differ: %d vs %d", len(data1), len(data2))
 	}
 }
 func TestProxy_Get_DifferentSizes(t *testing.T) {
 	t.Parallel()
 	svc, fixtures := setupTestProxy(t)
 	ctx := context.Background()
 	// Request same image at different sizes
 	sizes := []imagerequest.Size{
 		{Width: 25, Height: 25},
 		{Width: 50, Height: 50},
 		{Width: 75, Height: 75},
 	}
 	responses := make([][]byte, 0, len(sizes))
 	for _, size := range sizes {
 		req := &imagerequest.Request{
 			Source: imagerequest.Source{
 				Host: fixtures.GoodHost,
 				Path: testPathPhoto,
 			},
 			Transform: imagerequest.Transform{
 				Size:    size,
 				Format:  imagerequest.FormatJPEG,
 				Quality: 85,
 				FitMode: imagerequest.FitCover,
 			},
 		}
 		resp, err := svc.Get(ctx, req)
 		if err != nil {
 			t.Fatalf("Get() error for size %v = %v", size, err)
 		}
 		data, err := io.ReadAll(resp.Content)
 		if err != nil {
 			t.Fatalf("failed to read response: %v", err)
 		}
 		_ = resp.Content.Close()
 		responses = append(responses, data)
 	}
 	// All responses should be different sizes (different cache entries)
 	for i := range len(responses) - 1 {
 		if len(responses[i]) == len(responses[i+1]) {
 			// Not necessarily an error, but worth noting
 			t.Logf("responses %d and %d have same size: %d bytes",
 				i, i+1, len(responses[i]))
 		}
 	}
 }
 func TestProxy_Get_ContextCancellation(t *testing.T) {
 	t.Parallel()
 	svc, fixtures := setupTestProxy(t)
 	ctx, cancel := context.WithCancel(context.Background())
 	cancel() // Cancel immediately
 	req := &imagerequest.Request{
 		Source: imagerequest.Source{
 			Host: fixtures.GoodHost,
 			Path: testPathPhoto,
 		},
 		Transform: imagerequest.Transform{
 			Size:    imagerequest.Size{Width: 50, Height: 50},
 			Format:  imagerequest.FormatJPEG,
 			Quality: 85,
 			FitMode: imagerequest.FitCover,
 		},
 	}
 	_, err := svc.Get(ctx, req)
 	if err == nil {
 		t.Error("Get() expected error for cancelled context")
 	}
 }
 func TestProxy_Get_ReturnsETag(t *testing.T) {
 	t.Parallel()
 	svc, fixtures := setupTestProxy(t)
 	ctx := context.Background()
 	req := &imagerequest.Request{
 		Source: imagerequest.Source{
 			Host: fixtures.GoodHost,
 			Path: testPathPhoto,
 		},
 		Transform: imagerequest.Transform{
 			Size:    imagerequest.Size{Width: 50, Height: 50},
 			Format:  imagerequest.FormatJPEG,
 			Quality: 85,
 			FitMode: imagerequest.FitCover,
 		},
 	}
 	resp, err := svc.Get(ctx, req)
 	if err != nil {
 		t.Fatalf("Get() error = %v", err)
 	}
 	defer func() { _ = resp.Content.Close() }()
 	// ETag should be set
 	if resp.ETag == "" {
 		t.Error("ETag should be set in response")
 	}
 	// ETag should be properly quoted
 	if len(resp.ETag) < 2 || resp.ETag[0] != '"' || resp.ETag[len(resp.ETag)-1] != '"' {
 		t.Errorf("ETag should be quoted, got %q", resp.ETag)
 	}
 }
 func TestProxy_Get_ETagConsistency(t *testing.T) {
 	t.Parallel()
 	svc, fixtures := setupTestProxy(t)
 	ctx := context.Background()
 	req := &imagerequest.Request{
 		Source: imagerequest.Source{
 			Host: fixtures.GoodHost,
 			Path: testPathPhoto,
 		},
 		Transform: imagerequest.Transform{
 			Size:    imagerequest.Size{Width: 50, Height: 50},
 			Format:  imagerequest.FormatJPEG,
 			Quality: 85,
 			FitMode: imagerequest.FitCover,
 		},
 	}
 	// First request
 	resp1, err := svc.Get(ctx, req)
 	if err != nil {
 		t.Fatalf("Get() first request error = %v", err)
 	}
 	etag1 := resp1.ETag
 	_ = resp1.Content.Close()
 	// Second request (from cache)
 	resp2, err := svc.Get(ctx, req)
 	if err != nil {
 		t.Fatalf("Get() second request error = %v", err)
 	}
 	etag2 := resp2.ETag
 	_ = resp2.Content.Close()
 	// ETags should be identical for the same content
 	if etag1 != etag2 {
 		t.Errorf("ETags should match: %q != %q", etag1, etag2)
 	}
 }
 func TestProxy_Get_DifferentETagsForDifferentContent(t *testing.T) {
 	t.Parallel()
 	svc, fixtures := setupTestProxy(t)
 	ctx := context.Background()
 	// Request same image at different sizes - should get different ETags
 	req1 := &imagerequest.Request{
 		Source: imagerequest.Source{
 			Host: fixtures.GoodHost,
 			Path: testPathPhoto,
 		},
 		Transform: imagerequest.Transform{
 			Size:    imagerequest.Size{Width: 25, Height: 25},
 			Format:  imagerequest.FormatJPEG,
 			Quality: 85,
 			FitMode: imagerequest.FitCover,
 		},
 	}
 	req2 := &imagerequest.Request{
 		Source: imagerequest.Source{
 			Host: fixtures.GoodHost,
 			Path: testPathPhoto,
 		},
 		Transform: imagerequest.Transform{
 			Size:    imagerequest.Size{Width: 50, Height: 50},
 			Format:  imagerequest.FormatJPEG,
 			Quality: 85,
 			FitMode: imagerequest.FitCover,
 		},
 	}
 	resp1, err := svc.Get(ctx, req1)
 	if err != nil {
 		t.Fatalf("Get() first request error = %v", err)
 	}
 	etag1 := resp1.ETag
 	_ = resp1.Content.Close()
 	resp2, err := svc.Get(ctx, req2)
 	if err != nil {
 		t.Fatalf("Get() second request error = %v", err)
 	}
 	etag2 := resp2.ETag
 	_ = resp2.Content.Close()
 	// ETags should be different for different content
 	if etag1 == etag2 {
 		t.Error("ETags should differ for different sizes")
 	}
 }
@@ -1,213 +0,0 @@
 package imageproxy
 import (
 	"os"
 	"testing"
 	"time"
 	"sneak.berlin/go/pixa/internal/imageprocessor"
 	"sneak.berlin/go/pixa/internal/imagerequest"
 )
 // metricValues holds the source cache, upstream fetch and transform metrics
 // of a proxy and its cache. A histogram is given by its count of
 // observations.
 type metricValues struct {
 	sourceCacheHits   uint64
 	sourceCacheMisses uint64
 	fetchDurations    uint64
 	fetchErrors       uint64
 	transformDuration uint64
 	inProgress        float64
 }
 // readMetricValues reads the metrics of svc and its cache that
 // metricValues holds from their metrics registry.
 func readMetricValues(t *testing.T, svc *testProxy) metricValues {
 	t.Helper()
 	families, err := svc.registry.Gather()
 	if err != nil {
 		t.Fatalf("failed to gather the metrics: %v", err)
 	}
 	var values metricValues
 	for _, family := range families {
 		metric := family.GetMetric()[0]
 		switch family.GetName() {
 		case "pixa_source_cache_hits_total":
 			values.sourceCacheHits = uint64(metric.GetCounter().GetValue())
 		case "pixa_source_cache_misses_total":
 			values.sourceCacheMisses = uint64(metric.GetCounter().GetValue())
 		case "pixa_upstream_fetch_duration_seconds":
 			values.fetchDurations = metric.GetHistogram().GetSampleCount()
 		case "pixa_upstream_fetch_errors_total":
 			values.fetchErrors = uint64(metric.GetCounter().GetValue())
 		case "pixa_transform_duration_seconds":
 			values.transformDuration = metric.GetHistogram().GetSampleCount()
 		case "pixa_transforms_in_progress":
 			values.inProgress = metric.GetGauge().GetValue()
 		}
 	}
 	return values
 }
 // TestProxy_Get_CountsSourceCacheFetchesAndTransforms walks Get through a
 // miss that fetches the source, a hit, a miss that uses the cached source
 // and a miss whose source is not found upstream, checking the source cache,
 // upstream fetch and transform metrics after each.
 func TestProxy_Get_CountsSourceCacheFetchesAndTransforms(t *testing.T) {
 	t.Parallel()
 	svc, fixtures := setupTestProxy(t)
 	// want is source cache hits, source cache misses, fetch durations
 	// observed, fetch errors, transform durations observed, transforms in
 	// progress.
 	steps := []struct {
 		name    string
 		path    string
 		size    int
 		wantErr bool
 		want    metricValues
 	}{
 		{"miss that fetches the source", testPathPhoto, 50, false,
 			metricValues{0, 1, 1, 0, 1, 0}},
 		{"hit", testPathPhoto, 50, false,
 			metricValues{0, 1, 1, 0, 1, 0}},
 		{"miss that uses the cached source", testPathPhoto, 25, false,
 			metricValues{1, 1, 1, 0, 2, 0}},
 		{"miss whose source is not found", "/images/absent.jpg", 50, true,
 			metricValues{1, 2, 1, 1, 2, 0}},
 	}
 	for _, step := range steps {
 		resp, err := svc.Get(t.Context(), &imagerequest.Request{
 			Source: imagerequest.Source{
 				Host: fixtures.GoodHost,
 				Path: step.path,
 			},
 			Transform: imagerequest.Transform{
 				Size:    imagerequest.Size{Width: step.size, Height: step.size},
 				Format:  imagerequest.FormatJPEG,
 				Quality: 85,
 				FitMode: imagerequest.FitCover,
 			},
 		})
 		if (err != nil) != step.wantErr {
 			t.Fatalf("%s: Get() error = %v, want error %t", step.name, err, step.wantErr)
 		}
 		if err == nil {
 			_ = resp.Content.Close()
 		}
 		got := readMetricValues(t, svc)
 		t.Logf("after the %s: metrics = %+v", step.name, got)
 		if got != step.want {
 			t.Fatalf("after the %s: metrics = %+v, want %+v", step.name, got, step.want)
 		}
 	}
 }
 // TestProxy_Get_CountsMissingSourceFileAsSourceCacheMiss deletes the file of
 // a cached source but keeps its row. A request for a second variant of that
 // source must fetch the source again, and count a source cache miss, not a
 // hit.
 func TestProxy_Get_CountsMissingSourceFileAsSourceCacheMiss(t *testing.T) {
 	t.Parallel()
 	svc, fixtures := setupTestProxy(t)
 	// A first request caches the photo as a source.
 	resp, err := svc.Get(t.Context(), widthOnlyRequest(fixtures, 50))
 	if err != nil {
 		t.Fatalf("first Get() error = %v", err)
 	}
 	_ = resp.Content.Close()
 	source := widthOnlyRequest(fixtures, 50).Source
 	err = os.Remove(sourceFilePath(svc, source.Key()))
 	if err != nil {
 		t.Fatalf("failed to delete the cached source file: %v", err)
 	}
 	before := readMetricValues(t, svc)
 	resp, err = svc.Get(t.Context(), widthOnlyRequest(fixtures, 25))
 	if err != nil {
 		t.Fatalf("Get() of a second variant error = %v", err)
 	}
 	_ = resp.Content.Close()
 	after := readMetricValues(t, svc)
 	t.Logf("before the second variant: metrics = %+v; after: %+v", before, after)
 	if after.sourceCacheHits != before.sourceCacheHits ||
 		after.sourceCacheMisses != before.sourceCacheMisses+1 {
 		t.Errorf("source cache hits went from %d to %d and misses from %d to %d, "+
 			"want no new hit and one more miss", before.sourceCacheHits,
 			after.sourceCacheHits, before.sourceCacheMisses, after.sourceCacheMisses)
 	}
 }
 // TestProxy_Get_CountsTransformWaitingForSlotAsInProgress holds the only
 // processing slot and starts a request that must transform the photo. While
 // the request waits for the slot, pixa_transforms_in_progress must be 1; once
 // the request returns, 0.
 func TestProxy_Get_CountsTransformWaitingForSlotAsInProgress(t *testing.T) {
 	t.Parallel()
 	svc, fixtures := setupTestProxy(t)
 	svc.processor = imageprocessor.New(
 		imageprocessor.Params{MaxInputBytes: 50 << 20, MaxConcurrentProcessing: 1},
 	)
 	release := holdProcessingSlot(t, svc.processor)
 	result := startGet(t.Context(), svc, widthOnlyRequest(fixtures, 50))
 	// The request fetches the photo first, then waits for the slot.
 	deadline := time.Now().Add(5 * time.Second)
 	for readMetricValues(t, svc).inProgress != 1 && time.Now().Before(deadline) {
 		time.Sleep(10 * time.Millisecond)
 	}
 	waiting := readMetricValues(t, svc).inProgress
 	t.Logf("while the request waits for the slot: transforms in progress = %v",
 		waiting)
 	select {
 	case got := <-result:
 		t.Fatalf("Get() returned while the only processing slot was held, "+
 			"error = %v", got.err)
 	default:
 	}
 	if waiting != 1 {
 		t.Fatalf("transforms in progress = %v while the request waits for the "+
 			"slot, want 1", waiting)
 	}
 	release()
 	got := <-result
 	if got.err != nil {
 		t.Fatalf("Get() error = %v", got.err)
 	}
 	returned := readMetricValues(t, svc).inProgress
 	t.Logf("once the request returned: transforms in progress = %v", returned)
 	if returned != 0 {
 		t.Errorf("transforms in progress = %v once the request returned, want 0",
 			returned)
 	}
 }
@@ -1,84 +0,0 @@
 package imageproxy
 import (
 	"errors"
 	"os"
 	"testing"
 	"sneak.berlin/go/pixa/internal/imagerequest"
 )
 // TestProxy_Get_ServesCachedVariantOfNegativeCachedURL caches a variant of
 // the test photo, then keeps a failed fetch of the photo's URL in the negative
 // cache, as a failed fetch for another variant does once the source has been
 // evicted. The cached variant is still served, and a variant not in the cache
 // is made from the cached source. Once the source is evicted, a variant not in
 // the cache needs a fetch and is refused.
 func TestProxy_Get_ServesCachedVariantOfNegativeCachedURL(t *testing.T) {
 	t.Parallel()
 	svc, fixtures := setupTestProxy(t)
 	resp, err := svc.Get(t.Context(), photoVariant(fixtures, 85, imagerequest.FitCover))
 	if err != nil {
 		t.Fatalf("Get() first request error = %v", err)
 	}
 	_ = resp.Content.Close()
 	err = svc.cache.PutFailure(t.Context(),
 		photoVariant(fixtures, 85, imagerequest.FitCover).Source)
 	if err != nil {
 		t.Fatalf("PutFailure() error = %v", err)
 	}
 	resp, err = svc.Get(t.Context(), photoVariant(fixtures, 85, imagerequest.FitCover))
 	if err != nil {
 		t.Fatalf("Get() of the cached variant error = %v", err)
 	}
 	_ = resp.Content.Close()
 	if resp.CacheStatus != CacheHit {
 		t.Errorf("cached variant CacheStatus = %q, want %q",
 			resp.CacheStatus, CacheHit)
 	}
 	resp, err = svc.Get(t.Context(), photoVariant(fixtures, 40, imagerequest.FitCover))
 	t.Logf("Get() of a variant made from the cached source: error = %v", err)
 	if err != nil {
 		t.Fatalf("Get() of a variant made from the cached source error = %v", err)
 	}
 	_ = resp.Content.Close()
 	source := photoVariant(fixtures, 85, imagerequest.FitCover).Source
 	reader, _, _, err := svc.cache.Source(t.Context(), source)
 	if err != nil {
 		t.Fatalf("Source() error = %v, want the cached source", err)
 	}
 	_ = reader.Close()
 	// Evicts the source as the cache's eviction does: its row, then its file
 	_, err = svc.db.ExecContext(t.Context(),
 		`DELETE FROM source_content WHERE source_key = ?`, string(source.Key()))
 	if err != nil {
 		t.Fatalf("deleting the source's row: %v", err)
 	}
 	err = os.Remove(sourceFilePath(svc, source.Key()))
 	if err != nil {
 		t.Fatalf("removing the source's file: %v", err)
 	}
 	_, err = svc.Get(t.Context(), photoVariant(fixtures, 60, imagerequest.FitCover))
 	t.Logf("Get() of a variant whose source was evicted: error = %v", err)
 	if !errors.Is(err, ErrNegativeCached) {
 		t.Errorf("Get() of a variant whose source was evicted error = %v, want %v",
 			err, ErrNegativeCached)
 	}
 }
@@ -1,184 +0,0 @@
 package imageproxy
 import (
 	"bytes"
 	"io"
 	"os"
 	"testing"
 	"sneak.berlin/go/pixa/internal/imagerequest"
 	"sneak.berlin/go/pixa/internal/imgcache"
 )
 // getImage calls Get for req and returns the image it answered with and
 // its cache status.
 func getImage(
 	t *testing.T, svc *testProxy, req *imagerequest.Request,
 ) ([]byte, CacheStatus) {
 	t.Helper()
 	resp, err := svc.Get(t.Context(), req)
 	if err != nil {
 		t.Fatalf("Get() of quality %d error = %v", req.Transform.Quality, err)
 	}
 	defer func() { _ = resp.Content.Close() }()
 	body, err := io.ReadAll(resp.Content)
 	if err != nil {
 		t.Fatalf("reading the image of quality %d: %v", req.Transform.Quality, err)
 	}
 	return body, resp.CacheStatus
 }
 // fileSize returns the size of the file at path.
 func fileSize(t *testing.T, path string) int64 {
 	t.Helper()
 	info, err := os.Stat(path)
 	if err != nil {
 		t.Fatalf("stat %s: %v", path, err)
 	}
 	return info.Size()
 }
 // cachedSourcePath returns the path of the cached source file req uses.
 func cachedSourcePath(
 	t *testing.T, svc *testProxy, req *imagerequest.Request,
 ) string {
 	t.Helper()
 	reader, _, _, err := svc.cache.Source(t.Context(), req.Source)
 	if err != nil {
 		t.Fatalf("Source() error = %v; want the cached source", err)
 	}
 	_ = reader.Close()
 	return sourceFilePath(svc, req.Source.Key())
 }
 // TestProxy_Get_FetchesAgainForRemovedCachedSource removes the cached
 // source's row and file, as the reconciliation pass does when the file is
 // empty or cut short. internal/imgcache tests that the pass does so. The
 // test then asks for two new sizes of the source. The first must fetch it
 // again and cache it whole, so the second is made from the cache without a
 // third fetch.
 func TestProxy_Get_FetchesAgainForRemovedCachedSource(t *testing.T) {
 	t.Parallel()
 	svc, fixtures := setupTestProxy(t)
 	getImage(t, svc, photoVariant(fixtures, 85, imagerequest.FitCover))
 	source := photoVariant(fixtures, 85, imagerequest.FitCover).Source
 	path := cachedSourcePath(t, svc, photoVariant(fixtures, 85, imagerequest.FitCover))
 	wholeSize := fileSize(t, path)
 	// Removes the source as the reconciliation pass does: its row, then its file
 	_, err := svc.db.ExecContext(t.Context(),
 		`DELETE FROM source_content WHERE source_key = ?`, string(source.Key()))
 	if err != nil {
 		t.Fatalf("deleting the source's row: %v", err)
 	}
 	err = os.Remove(path)
 	if err != nil {
 		t.Fatalf("removing the source's file: %v", err)
 	}
 	getImage(t, svc, photoVariant(fixtures, 40, imagerequest.FitCover))
 	getImage(t, svc, photoVariant(fixtures, 30, imagerequest.FitCover))
 	fetches := readCounters(t, svc).upstreamFetchCount
 	t.Logf("upstream fetches = %d", fetches)
 	if fetches != 2 {
 		t.Errorf("upstream fetches = %d, want 2", fetches)
 	}
 	size := fileSize(t, path)
 	if size != wholeSize {
 		t.Errorf("cached source is %d bytes, want %d", size, wholeSize)
 	}
 }
 // TestProxy_Get_FetchesAgainSourceOfNoSourceFormat replaces the cached
 // source's file with text. The next request for a new size of the source
 // must fetch it again and cache it whole.
 func TestProxy_Get_FetchesAgainSourceOfNoSourceFormat(t *testing.T) {
 	t.Parallel()
 	svc, fixtures := setupTestProxy(t)
 	getImage(t, svc, photoVariant(fixtures, 85, imagerequest.FitCover))
 	path := cachedSourcePath(t, svc, photoVariant(fixtures, 85, imagerequest.FitCover))
 	wholeSize := fileSize(t, path)
 	err := os.WriteFile(path, []byte("this is text, not an image"),
 		imgcache.StorageFilePerm)
 	if err != nil {
 		t.Fatalf("replacing the source's file: %v", err)
 	}
 	getImage(t, svc, photoVariant(fixtures, 40, imagerequest.FitCover))
 	fetches := readCounters(t, svc).upstreamFetchCount
 	t.Logf("upstream fetches = %d", fetches)
 	if fetches != 2 {
 		t.Errorf("upstream fetches = %d, want 2", fetches)
 	}
 	size := fileSize(t, path)
 	if size != wholeSize {
 		t.Errorf("cached source is %d bytes, want %d", size, wholeSize)
 	}
 }
 // TestProxy_Get_ConvertsAgainForRemovedCachedVariant caches a variant of
 // the photo and removes its row and file, as the reconciliation pass does
 // when the file is empty or cut short. internal/imgcache tests that the
 // pass does so. The test then checks that Get converts the image again, and
 // that the next Get serves the whole variant from the cache.
 func TestProxy_Get_ConvertsAgainForRemovedCachedVariant(t *testing.T) {
 	t.Parallel()
 	svc, fixtures := setupTestProxy(t)
 	req := photoVariant(fixtures, 85, imagerequest.FitCover)
 	want, _ := getImage(t, svc, req)
 	key := imagerequest.CacheKey(req)
 	// Removes the variant as the reconciliation pass does: its row, then its file
 	_, err := svc.db.ExecContext(t.Context(),
 		`DELETE FROM variant_content WHERE cache_key = ?`, string(key))
 	if err != nil {
 		t.Fatalf("deleting the variant's row: %v", err)
 	}
 	err = os.Remove(variantFilePath(svc, key))
 	if err != nil {
 		t.Fatalf("removing the variant's file: %v", err)
 	}
 	got, status := getImage(t, svc, req)
 	t.Logf("after the removal: %d bytes, %s", len(got), status)
 	if status != CacheMiss || !bytes.Equal(got, want) {
 		t.Errorf("after the removal: Get() = %d bytes, %s; want the %d bytes "+
 			"converted again, %s", len(got), status, len(want), CacheMiss)
 	}
 	got, status = getImage(t, svc, req)
 	t.Logf("next request: %d bytes, %s", len(got), status)
 	if status != CacheHit || !bytes.Equal(got, want) {
 		t.Errorf("next request: Get() = %d bytes, %s; want the %d bytes, %s",
 			len(got), status, len(want), CacheHit)
 	}
 }
@@ -1,78 +0,0 @@
 package imageproxy
 import (
 	"context"
 	"database/sql"
 	"errors"
 	"testing"
 	"time"
 	"sneak.berlin/go/pixa/internal/imagerequest"
 )
 // pendingAccessTimesWait is how long a test waits for the database's
 // connection, for a cache hit to be answered, for an access time to reach
 // the database, or for a request to return past its deadline.
 const pendingAccessTimesWait = 5 * time.Second
 // holdDatabase takes the one connection of db, so that every other query
 // waits for it, and returns the func that frees it.
 func holdDatabase(t *testing.T, db *sql.DB) func() {
 	t.Helper()
 	ctx, cancel := context.WithTimeout(t.Context(), pendingAccessTimesWait)
 	defer cancel()
 	conn, err := db.Conn(ctx)
 	if err != nil {
 		t.Fatalf("failed to take the database connection: %v", err)
 	}
 	return func() { _ = conn.Close() }
 }
 // TestProxy_Get_ReturnsByItsDeadlineWhileTheDatabaseIsBusy holds the
 // database's one connection while a request whose fetch is held reaches its
 // deadline. The request must return with the deadline's error while the
 // connection is still held, as it waits for no database write past its
 // deadline.
 func TestProxy_Get_ReturnsByItsDeadlineWhileTheDatabaseIsBusy(t *testing.T) {
 	t.Parallel()
 	svc, fixtures, fetcher := setupHeldFetchProxy(t)
 	svc.cache.StartPendingAccessTimeWrites()
 	defer func() { _ = svc.cache.StopPendingAccessTimeWrites(t.Context()) }()
 	// Room for the request to reach its fetch on a busy host
 	const timeout = 2 * time.Second
 	ctx, cancel := context.WithTimeout(t.Context(), timeout)
 	defer cancel()
 	deadline, _ := ctx.Deadline()
 	results := startGet(ctx, svc, photoVariant(fixtures, 85, imagerequest.FitCover))
 	// The request has made its database reads by the time it fetches.
 	select {
 	case <-fetcher.started:
 	case <-time.After(timeout):
 		t.Fatal("request did not reach its fetch by its deadline")
 	}
 	releaseDatabase := holdDatabase(t, svc.db)
 	defer releaseDatabase()
 	select {
 	case got := <-results:
 		t.Logf("Get() returned %v after its deadline, error = %v",
 			time.Since(deadline), got.err)
 		if !errors.Is(got.err, context.DeadlineExceeded) {
 			t.Errorf("Get() error = %v, want %v", got.err, context.DeadlineExceeded)
 		}
 	case <-time.After(time.Until(deadline) + pendingAccessTimesWait):
 		t.Fatal("request did not return while the database was busy")
 	}
 }