Define ContentHash, VariantKey, and PathHash types to replace
raw strings, providing compile-time type safety for storage
operations. Update storage layer to use typed parameters,
refactor cache to use variant storage keyed by VariantKey,
and implement source content reuse on cache misses.
Add trailing filename to encrypted URLs for better browser compatibility.
The filename is ignored by the server but helps browsers identify content type.
Since signing_key is now required at config load time, sessMgr, encGen,
and signer are always initialized. Remove unnecessary nil checks that
were runtime failure paths that can no longer be reached.
- handlers.go: Remove conditional init, always create sessMgr/encGen
- auth.go: Remove nil checks for sessMgr
- imageenc.go: Remove nil check for encGen
- service.go: Require signing_key in NewService, remove signer nil checks
- Update tests to provide signing_key
- Middleware now tracks and logs bytes written via response_bytes
- Handler logs cache_key for cache hit debugging
- Changed "served encrypted image" to "image served" (only URL is encrypted)
- Capture TLS version, cipher suite, HTTP version, and remote addr
- Add download bitrate using go-humanize SI formatting
- Use consistent WxH format for dimensions (not struct notation)
- Rename input/output to src/dst for consistency
- Add separate "upstream fetched" log with connection details
- Return ErrUnsupportedOutputFormat for WebP/AVIF encoding
- Return ErrInvalidFitMode for unknown fit mode values
- Add ValidateFitMode() for input validation
- Validate fit mode at handler level before processing
Silent fallbacks violate the principle of least surprise and mask bugs.
When a user explicitly specifies a value, we should either honor it or
return an error - never silently substitute a different value.
- Make ExpiresAt optional in CBOR (omitempty) for smaller tokens
- Treat ExpiresAt=0 as 'never expires' in parser
- URL-encode token with url.PathEscape() for safety
- Add 'Never' as default TTL option in generator form
TDD: Write tests first before implementation for:
- ETag generation and consistency in service layer
- HEAD request support (headers only, no body)
- Conditional requests with If-None-Match header (304 responses)
- StoreOutput now returns output hash for immediate retrieval
- Cache misses now serve from disk file after storing (same as hits)
- Log served_bytes from actual io.Copy result (avoids stat calls)
- Remove ContentLength field usage for cache hits (stream from file)
- Fix tests to properly check all return values
