A cached source and its variants were served until eviction, so a
changed image at the same URL was never picked up.
Once a source was last checked 24 hours ago, the next request for one
of its images asks upstream with If-None-Match and If-Modified-Since,
from the ETag and Last-Modified it stored. A 304 renews the source and
its variant without a download or a conversion. New bytes replace the
source, and each variant made before them is converted again. A failed
check serves the cached image and puts the URL in the negative cache.
Sources and variants not checked successfully for 30 days are evicted.
A variant file's modification time is its source's check time, so a
hit still makes no database call.
Existing tests change only in call signatures. The test that asserted
two-day-old entries are served without asking upstream is replaced by
the new ones.
Model: opus-5-5
magic.DetectFormat returns an imagerequest.Format. ValidateMagicBytes
returns the format it checked against the upstream Content-Type. The
cache reads a cached source's format from its file's first bytes, as it
reads a variant's. The proxy hands the format to Process. Process
refuses a format that is not a source format, and input libvips would
load with another loader, such as an SVG passing as AVIF.
Format.MIMEType declares each MIME string once, and the fetcher, the
cache's variant read and the Accept matching use it. magic.MIMEType,
magic.ImageFormat, MIMEToImageFormat, magic's SVG detection,
detectFormat, formatFromString, FormatToMIME and Result.InputFormat are
gone.
Model: opus-5-5
The image request now holds only its source and its transform, exactly what
the variant key covers. The /v1/image/ handler checks the allowlist and
verifies the signature itself with Signer.Verify(req, sig, expires). Both
image handlers keep the URL's expiry as a local value for Cache-Control. The
image service holds no signer, allowlist or AllowHTTP, and ValidateRequest is
gone. The fetcher takes the source and builds its URL with Source.URL from its
own AllowHTTP, so no URL string is built and parsed again. chooseAutoFormat
returns the format it chooses instead of writing into the request. The signed
URL format and every route's answers are unchanged.
Model: opus-5-5
A JPEG XL source is accepted, and orig of one is JPEG XL. The format
jxl works in plain and encrypted URLs and on the generator page,
served as image/jxl; auto chooses it first when Accept names
image/jxl.
govips sends libvips a JPEG XL distance, which overrides the quality,
so q becomes a distance, keeping 100 lossy. Metadata is removed from
the image before the JPEG XL save, as govips cannot have libvips strip
it, and the image is given 72 dpi so that the EXIF block libvips 8.16
adds holds nothing from the source. The sRGB conversion moved ahead of
the format switch, and a CMYK image with no ICC profile is converted
to sRGB, as libvips cannot save CMYK as JPEG XL.
Model: opus-5-5
Accumulating milestone branch. One squashed commit per closed issue; `next` is kept green and mergeable to `main` at any time without notice.
Landed so far:
- `chore: update golangci-lint to v2.12.2 with canonical config` (#54) — canonical v2-schema `.golangci.yml`, pins bumped in `Dockerfile` and `script/bootstrap`, tree at `0 issues.`. Three behaviour deltas are recorded in that PR's body: `Cache.StoreVariant` takes a context, `MetadataStorage.Store` no longer leaks temp files on failure, and the `signing_key` too-short error text gained a `value too short:` prefix.
Sequencing for the milestone is tracked in #103.
Reviewed-on: #105
Co-authored-by: clawbot <clawbot@noreply.example.org>
Extracts the HTTP fetcher concern out of `internal/imgcache/` into its own `internal/httpfetcher/` package, per the plan in [issue #39](#39).
This is one of four planned extractions; only the fetcher is moved here so the diff stays reviewable. The remaining three (signature, magic, urlparser) will land in separate PRs.
## What moved
From `internal/imgcache/fetcher.go` and `internal/imgcache/mock_fetcher.go` into `internal/httpfetcher/`:
- `HTTPFetcher` type, its `New` constructor, and `Config` (formerly `FetcherConfig`) with `DefaultConfig`
- SSRF-safe dialer, `validateURL`, `isPrivateIP`, `isLocalhost`, `extractHost`
- Per-host connection semaphore (rate limiting) and `limitedReader`
- Content-type validation (`isAllowedContentType`, `detectContentTypeFromPath`)
- All related error values (`ErrSSRFBlocked`, `ErrUpstreamError`, `ErrUpstreamTimeout`, `ErrPayloadTooLarge`, `ErrDisallowedContentType`)
- All related constants (`DefaultFetchTimeout`, `DefaultMaxPayloadBytes`, `DefaultMaxConnectionsPerHost`, etc.)
- The `Fetcher` interface and `FetchResult` type (moved here to keep the import edge one-way: `imgcache` depends on `httpfetcher`, never the reverse)
- `MockFetcher` test helper
## Renames (no stuttering)
- `NewHTTPFetcher` → `httpfetcher.New`
- `FetcherConfig` → `httpfetcher.Config`
- `DefaultFetcherConfig` → `httpfetcher.DefaultConfig`
- `NewMockFetcher` → `httpfetcher.NewMock`
The `ServiceConfig.FetcherConfig` field name is retained — it describes what kind of config the field holds (not a stutter).
## Behavior
Pure refactor. No behavior changes. All existing tests pass; unit tests for the new package are included.
`docker build .` passes (fmt-check, lint, test, build).
refs #39
Co-authored-by: clawbot <clawbot@eeqj.de>
Co-authored-by: Jeffrey Paul <sneak@noreply.example.org>
Reviewed-on: #43
Co-authored-by: clawbot <clawbot@noreply.example.org>
Co-committed-by: clawbot <clawbot@noreply.example.org>
clawbot
