Closes Scribe #614, #615, server half of #616 surfaced by the 2026-06-04 divergent-provider audit.
- streamURL helper now used everywhere /api/tracks/{id}/stream is built (was inline concat in playlists.go and cast_token.go); add streamURLWithExt for the .ext cast variant.
- audioContentType in media.go is the canonical file_format -> MIME lookup; mimeForFormat in cast_token.go is now a thin wrapper that overrides the unknown-format fallback to audio/mpeg (Sonos rejects octet-stream). Adds mpeg/vorbis/wave aliases. Subsonic's contentTypeForFormat stays frozen per docs.
- coverart.ResolveAlbumPath extracted; api and subsonic both delegate to it.
After the X-Forwarded-Proto fix Sonos now gets a clean https:// URL
but returns vendor error 1023 - empty CurrentURIMetaData. Sonos
requires DIDL-Lite metadata with at minimum <res protocolInfo>
carrying the audio MIME type so it can validate the source before
playback. The original spec said 'Sonos accepts empty DIDL; recoverable
if a device rejects' - that was wrong for Sonos.
Server (cast_token.go):
- Look up the track and return mime (from tracks.file_format) +
title in the cast-token response. mimeForFormat covers the common
formats - mp3, flac, m4a/aac, ogg, opus, wav - falling through to
audio/mpeg for unknowns.
- Missing track returns 404 (apierror.NotFound) instead of letting the
caller mint a token for nothing.
Client (CastApi.kt, AVTransportClient.kt, OutputPickerController.kt):
- StreamTokenResponse gains mime + title (defaulted so old contracts
stay parseable).
- AVTransportClient.setAVTransportURIWithMetadata builds minimal Sonos-
acceptable DIDL-Lite around the URL + MIME + title. xml-escaped.
- selectUpnp calls the new overload; Timber.i now logs the MIME so the
next on-device test shows it.
Generic UPnP renderers tolerate the DIDL shape too - no downside to
sending it everywhere.
On-device test against Sonos showed SetAVTransportURI returning UPnP
error 714 (IllegalMimeType). Logcat:
POST /api/cast/stream-token -> 200 (token minted)
SetAVTransportURI to http://minstrel.fabledsword.com/...
<-- 500 from Sonos: SoapFaultException SOAP fault 714
The server is behind a TLS-terminating reverse proxy, so r.TLS is
nil and the URL builder emitted http://. Sonos does a HEAD probe to
detect the audio MIME type; against an http:// URL that 301s to
https://, the probe finds no audio body and bails with 714.
The Task 2 code-quality reviewer flagged this exact scenario at the
time. Closing it now: honor X-Forwarded-Proto + X-Forwarded-Host
before falling back to r.TLS + r.Host. Public URL the speaker
fetches now matches the scheme/host the client used to reach the
endpoint.
Adds the client-facing endpoint that issues a signed stream URL for
the current track. Authenticated via the standard session cookie.
Returns {token, exp, url} where url is a fully-formed stream URL
the client passes verbatim to a UPnP / Sonos device's
AVTransport.SetAVTransportURI call.
expSeconds clamped to [60, 86400]; default 21600 (6h) - long enough
to play through any typical track without re-minting mid-playback.
MINSTREL_STREAM_SECRET is loaded from env var with a per-machine
fallback persisted at <Storage.DataDir>/stream_secret (auto-generated
on first boot via 64 random bytes, base64-url-encoded, 0600). The
file-based fallback is operator-machine-scoped runtime state, not a
user-facing setting - chosen over a DB column to avoid a migration
and keep the secret out of cross-instance restores. Operator can
override at any time via the env var; default path requires zero
config.
Tests cover happy-path token issuance + URL formatting, bad-UUID
rejection, unauthenticated rejection, the expSeconds clamp at all
boundaries, secret env override, auto-gen + file persistence at 0600,
second-boot reuse of the persisted file, and rejection of a malformed
env value.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
bvandeusen