_matrix/client/unstable/org.matrix.msc2432/rooms/:room_id/aliases CORS issue

[matrixbot]

This issue was originally created by @thepra at matrix-org/dendrite#2570.

Background information

• Dendrite version or git SHA: 0.8.9
• Monolith or Polylith?: Monolith
• SQLite3 or Postgres?: Postgres
• Running in Docker?: No
• go version: 1.18.1
• Client used (if applicable): Cinny

Description

• What is the problem:
  This endpoint /_matrix/client/unstable/org.matrix.msc2432/rooms/:room_id/aliases?access_token=<redacted> is being called from a subdomain where the client lives(chat.<DOMAIN>, meanwhile the server at <DOMAIN>) and it's the only call that have CORS issues about Access-Control-Allow-Origin missing despite it is already set as a proxy_set_header Access-Control-Allow-Origin '*'; in nginx.

Is this a bug?

[matrixbot]

This comment was originally posted by @neilalexander at matrix-org/dendrite#2570 (comment).

In this instance, you are seeing a CORS error because the endpoint does not exist in Dendrite.

Seeing as MSC2432 was merged into the spec back in 2020, Dendrite instead implements the stable endpoint at /_matrix/client/r0/rooms/{roomId}/aliases and /_matrix/client/v3/rooms/{roomId}/aliases.

You should raise a bug with Cinny about incorrectly using an unstable endpoint for a stable feature.

[matrixbot]

This comment was originally posted by @thepra at matrix-org/dendrite#2570 (comment).

@neilalexander thanks for the answer :)
I did open an issue at cinny