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
Service.Warm, the ImageCache interface, both GenerateSignedURL methods,
signature.ParseParams, imagerequest.ParseImagePath, four symbols of
internal/magic, the image processor's lists of supported formats,
IsEmpty and Count of the allowlist, ssrfSafeDialer, CacheStale,
ErrCacheMiss, ErrNegativeCache, ImageResponse.LastModified and the Load
methods of ContentStorage and VariantStorage had no caller outside
tests. They are gone, with the tests that tested only them.
The handlers tests sign their image URLs with generateSignedURL, a test
helper that builds the URL as the removed generator did. The SSRF dialer
tests call dialSSRFSafe with no operator blocklist, which is all
ssrfSafeDialer did. The tests of ParseImagePath and ContentStorage.Load
call ParseImageURL and LoadWithSize instead. MIMEToImageFormat,
ContentStorage.Store and CleanExpired stay, as pixa calls them.
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>
## Summary
Extract magic byte detection and MIME type handling from `internal/imgcache/` into a new focused `internal/magic/` package.
Part of [issue #39](#39)
## Changes
### New package: `internal/magic/`
Moved the following from `internal/imgcache/magic.go`:
- `MIMEType` type and constants (`MIMETypeJPEG`, `MIMETypePNG`, etc.)
- `DetectFormat()` — detects image format from magic bytes
- `ValidateMagicBytes()` — validates content matches declared MIME type
- `PeekAndValidate()` — reads minimum bytes, validates, returns combined reader
- `IsSupportedMIMEType()` — checks if a MIME type is supported
- `MIMEToImageFormat()` — converts MIME type to ImageFormat
- `ImageFormatToMIME()` — converts ImageFormat to MIME string
- All error sentinels (`ErrUnknownFormat`, `ErrMagicByteMismatch`, `ErrNotEnoughData`)
- All helper functions (`detectSVG`, `skipBOM`, `normalizeMIMEType`)
The magic package defines its own `ImageFormat` type and constants to avoid circular imports (`imgcache` → `magic` for validation; `magic` cannot import `imgcache`).
### Updated imports
- `internal/imgcache/service.go`: uses `magic.ValidateMagicBytes()`
- `internal/imgcache/service_test.go`: uses `magic.DetectFormat()` and `magic.MIMEToImageFormat()`
### Naming
- Clean package-qualified names: `magic.DetectFormat()`, `magic.ValidateMagicBytes()`, etc.
- No stuttering names
### Tests
- Full test suite moved to `internal/magic/magic_test.go` (all 15 test functions preserved)
- All existing tests pass unchanged
- `docker build .` passes (includes `make check`: fmt, lint, tests)
Co-authored-by: user <user@Mac.lan guest wan>
Reviewed-on: #42
Co-authored-by: clawbot <clawbot@noreply.example.org>
Co-committed-by: clawbot <clawbot@noreply.example.org>
clawbot
