fix(desktop): forward cache headers in media proxy#549
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Codex review (gpt-5.5)Ran Verdict: No findings.
(Codex inspected both proxy paths, the relay-side cache-control source in |
WKWebView fetches images via the localhost media proxy and the sprout-media:// protocol handler. Both paths only forwarded a hard-coded allowlist of headers (content-type, content-range, accept-ranges, content-length) and stripped everything else — including `Cache-Control`, which the relay already sets to `public, max-age=31536000, immutable` for content-addressed media. Without those headers WKWebView treats every response as uncacheable and re-fetches every image on each channel switch. Forward `cache-control`, `etag`, and `last-modified` in both proxy paths. Media URLs are sha256-addressed, so the upstream's immutable caching directive is safe to honor verbatim. `etag`/`last-modified` are forwarded too in case the relay ever starts sending them. Signed-off-by: tlongwell-block <109685178+tlongwell-block@users.noreply.github.com>
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This was referenced May 28, 2026
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Why
Images re-download on every channel switch. The relay already sends
Cache-Control: public, max-age=31536000, immutablefor content-addressedmedia (see
crates/sprout-relay/src/api/media.rs), but the desktop'slocalhost media proxy and
sprout-media://protocol handler both forwardonly a hard-coded allowlist:
content-type,content-range,accept-ranges,content-lengthEverything else — including
Cache-Control— is stripped, so WKWebViewtreats every response as uncacheable.
What
Forward
cache-control,etag, andlast-modifiedin both code pathsin
desktop/src-tauri/src/media_proxy.rs.Media URLs are sha256-addressed, so honoring the upstream's immutable
caching directive verbatim is safe — the content at a given URL cannot
change.
etagandlast-modifiedare forwarded for future-proofing.Verification
just desktop-tauri-checkpasses.just desktop-tauri-fmt-checkpasses.hooks before merge (
just ci).Risk
Low. The change is additive — three more header names in a forwarding
allowlist. No behaviour change for responses where the relay doesn't
send the headers.