Second specialized renderer pair landing under RFC #2991. Stacks on
PR-1 (#2997) — extends the AttachmentPreview dispatcher with video/
audio cases.
Why HTML5-native (not custom JS player)
---------------------------------------
- Browser vendors ship hardware-accelerated decoders, captions,
pinch + scrub UX, and fullscreen UI. We get all of it for free.
- Native fullscreen via the <video> control bar — no
AttachmentLightbox needed for video (the browser's built-in
fullscreen handles it).
- Mobile-friendly without us writing the touch handlers.
Auth model
----------
Identical to AttachmentImage (PR-1): platform-auth URIs need our
cookie/token, so we fetch the bytes, wrap in a Blob, hand the
browser an ObjectURL via <video src=> / <audio src=>. External
http(s) URIs skip the fetch.
Memory caveat: a Blob holds the entire media in JS memory until the
bubble unmounts. The server's 25MB single-file cap (chat_files.go)
bounds this; v2 can switch to MediaSource + streaming if larger
files become a real shape.
Failure modes
-------------
- Fetch failure (404, 403, network) → AttachmentChip fallback.
- Bytes that aren't valid media (corrupt, wrong Content-Type) →
<video onError> / <audio onError> swap to chip.
Tests
-----
5 new component tests in AttachmentPreview.test.tsx (now 14 total):
- kind=video → <video controls> with blob URL src
- kind=video fetch fails → falls back to chip
- kind=video extension fallback (no mime) → routes to video path
- kind=audio → <audio controls> + filename label visible
- kind=audio fetch fails → falls back to chip
The preview-kind unit tests from PR-1 (49 cases) already cover the
MIME → video / audio dispatch logic; this PR's component tests pin
the rendered DOM shape (controls attribute, blob URL src, fallback
behavior).
Hostile self-review
-------------------
1. Memory bound: 25MB cap protects us today; documented future
migration path (MediaSource).
2. iOS Safari autoplay: playsInline pinned on <video> so mobile
doesn't auto-fullscreen on play.
3. Captions accessibility: <track kind="captions" /> placeholder so
the element is tagged correctly even though we don't have caption
files yet (forward-compatible).
Verified
- tsc --noEmit clean
- 173 chat tests green (49 unit + 14 component + 110 pre-existing)
Stacks on PR-1 (#2997). PR-3 (PDF + text/code) is the final piece.
Refs RFC #2991, PR #2997 (PR-1).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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