Two unrelated wins as a single batch.
Flutter — lazy source building in setQueueFromTracks:
Today: Future.wait builds all N AudioSource objects (drift queries +
LockCaching ctor) before the player can call setAudioSources →
play(). Measured at 83ms for a 25-track playlist, on top of the
~285ms initial-source preload.
New flow: build only the initial source, hand it to setAudioSources
([initial], initialIndex: 0) so play() can start, then background-
fill the rest. Forward direction (skipNext targets) added via
addAudioSource. Backward direction (skipPrev) inserted at index 0..
initialIndex-1 with _suppressIndexUpdates true so the unavoidable
currentIndex shifts don't push the wrong MediaItem onto the stream.
Saves the up-front source-build wait — tap-to-audio for long queues
should drop by ~80-100ms even on cache hits.
Server — Cache-Control on the three byte-serving endpoints:
- /api/albums/{id}/cover: max-age=86400, must-revalidate. Covers
change rarely (re-scan, MBID enrichment); a day of cache is safe
and skips conditional GETs for the bulk of a session.
- /api/playlists/{id}/cover: max-age=300, must-revalidate. Collages
recompute when contents change; short enough for edits to feel
fresh, long enough to skip repeat fetches during a session.
- /api/tracks/{id}/stream: max-age=31536000, immutable. Track bytes
are immutable for a given id (scanner re-indexes by file_path; new
files get new ids). LockCachingAudioSource on the Flutter side
already disk-caches, but proper headers let it skip even the
conditional 304 on repeat plays.
bvandeusen