code-server runs authenticateOrigin on every websocket and resolves the
request host as Forwarded, then X-Forwarded-Host, then Host. The forward
core put the public host into additional_headers, but the websockets
client already writes its own Host for the real TCP target and Headers
appends, so the handshake carried two Host lines; Node keeps the first
(the internal gateway:port), the origin check failed, and code-server
answered 403. Because the browser socket was accepted before the upstream
was dialled, that surfaced as a 101 followed by 1011 and the editor died
on "the workbench failed to connect to the server". Dialling first and
carrying the public host in the connect URI fixes both planes.
The two header builders that had drifted apart are now one core, so a
websocket carries the same client and forwarded headers as an HTTP
request. Responses stream instead of buffering whole, which is what makes
a large tunnel download cost constant memory and lets SSE work; byte
accounting moved onto the completion callback. Subprotocols negotiate,
the upstream client is reused across requests, and the path and query are
forwarded byte-exactly.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
retoorandClaude Opus 5
c0742994cd