Hydration stamped the album's hash and blurhash onto an embedded-eligible
track that had no state row yet. Serving takes provisionalEmbedded for
exactly that case and returns the track's own embedded image, so the id
carried a content-version belonging to a different picture: every such
request fell back to no-cache instead of immutable, and a client keying
its cover cache on the blurhash paired the album's with the track's art.
AlbumCoverArtID had the mirror-image problem, building the album id from
the track's own ItemImage. It happened to work only because hydration
overwrote ImageHash in precisely the fallback cases; a track with its own
resolved art would have stamped that hash onto the album's id.
loadTracks and the playlist-track cursor were the only entity-page
paths that never hydrated artwork state, so a song reached through a
playlist behaved differently from the same song in the songs list:
Subsonic emitted a hashless coverArt id, which imghttp downgrades to
no-cache, and advertised art even for known-absent albums; Jellyfin
emitted AlbumPrimaryImageTag as the bare album id — a tag that never
changes when the cover does — and no blurhash at all.
The media-file hydration moves next to the other hydration helpers so
both paths share one implementation rather than growing a third.
Entity-level artwork queries now take a typed model.Kind instead of a bare
prefix string. GetItemArtwork, DeleteForItem(s), GetInfoForItems,
EnqueueStaleAbsent, hydrateItemImages, enqueueBackfillKind and artwork.Refresh
convert to the prefix string only at the two real boundaries: the SQL
item_kind column (kind.Prefix() inside each repo) and external string inputs
(a new model.ParseKind for the nativeapi URL param, which also validates it).
The Backfill/stale-absent kind slices, the resolve.go dispatch switch, and the
kind→resource / kind→table lookup maps now use the Kind vars directly. The
queue lifecycle methods (MarkFailed/Delete*) keep string kinds — they operate
on a dequeued item's raw ItemKind column, which stays a string field, always
populated via kind.Prefix().
Removes every bare "al"/"ar"/… prefix literal from non-test code (27 -> 0);
behavior is unchanged.
Cleanups surfaced by /simplify: the song mapper's own-art branch reimplemented
primaryImageTag's tag+blurhash-map construction (and its one-entry invariant) — route
it through the helper so that invariant lives in one place. Tie artworkChunkSize to a
whole multiple of artworkBatchSize so a cursor page re-chunks into even hydration
batches. Hoist a duplicated imageLoading && blurHash boolean in the album grid.
The album, artist and playlist GetCursor built their own select and never
called hydrateArtwork, so every Jellyfin list endpoint (all six stream via
GetCursor) emitted entity-id image tags and no blurhash. Only GetAll
hydrated, which is why Subsonic and the native API were unaffected.
Each cursor now resolves its ordered/filtered/paginated id set with the
cheap id-only GetAllIDs query, then streams those ids in chunks through the
repo's existing GetAll, which already hydrates and applies the full select.
Max/Offset are consumed by the pre-pass alone; the chunk query carries only
the caller's filters, Sort and Order.
This also removes a pre-existing deep-pagination cost: keeping OFFSET out of
the joined query makes the pre-pass a covering index scan instead of paying
the library and annotation joins for every skipped row. Benchmarked on a
synthetic 100k-album DB with the real schema, page=500 at offset 90,000:
3.9ms via the id pre-pass, 52.5ms for the current shape, 192.7ms for a naive
join. An unpaginated full stream costs ~24% more, which is the trade.
GetAllIDs gains the annotation join whenever the caller's filters or sort
reference an annotation column (same gate CountAll uses), otherwise
Filters=IsFavorite and SortBy=PlayCount would fail in the pre-pass. The
playlist pre-pass repeats GetAll's columns so ORDER BY keeps resolving to
playlist.name rather than the joined user.name.
