Root cause of a downloaded/streaming video buffering repeatedly: every /files Range request
(a playing video fires dozens) re-ran the full attachment authorization, which scans the
messages table by attachment_id (un-indexed) — a per-chunk table scan = stutter. Now the
auth decision is cached per user+attachment for 60s (module-level, bounded), so range
requests after the first are ~free.
Also: preload='none' (nothing about a video downloads until the user taps play — only the
small poster loads), per 'no auto-download'. And the buffering spinner no longer hides on
canplay/loadeddata (they fire mid-buffer), so it reliably spins whenever it's buffering.
build batch159.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
SravanandClaude Opus 4.8
2127397408