The display controller and the viewer routes each described the
heartbeat their own way and disagreed about one thing: the display sent
null for "nothing to report", and the route accepted only a missing
field. Every heartbeat from a screen showing a native image was refused
with a 400. The roster therefore marked working screens Offline 90 s
after they opened, and never recorded offlineReady or cachedAssetCount.
src/shared/display-protocol.ts now defines every message between a
display and the server:
- viewer session request and response;
- heartbeat request and response;
- channel state;
- the realtime display payload.
Both halves import it. Its rules: a nullable field accepts null
explicitly, an absent field means "not reported", and an unknown field
is ignored, so a newer display is never refused by an older server.
- The routes parse with the shared parsers, and a refusal names the
field with Signage's sanitized code.
- The server's channel state extends the wire type, so a field the
display relies on cannot drift without a compile error.
- The display builds its heartbeat as the shared type, and reads its
registration with the shared parser instead of casting it.
- Test stubs that described server responses more loosely than the
server sends them (no viewerName, no stale, partial media) now match
the real responses and are typed as the protocol.
Co-Authored-By: Claude Opus 5.5 <[email protected]>
Every display test answered the controller with a hand-written stub, and
every viewer test called the service with a hand-written object, so
neither side was ever tested against the other. In production every
heartbeat was refused with a 400.
This suite answers the real controller's requests with the real viewer
route handlers over the in-memory store. The routes gain an optional
store factory for that; production still uses the module database.
Fails today: POST /viewers/:viewerId/heartbeat -> 400
SIGNAGE_INVALID_REQUEST, because the display sends
reportedContributionId: null and the route accepts only a missing field.
Co-Authored-By: Claude Opus 5.5 <[email protected]>
