Fails to log in if optional .well-known/matrix/client is not present

[affenull2345]

https://spec.matrix.org/latest/client-server-api/#well-known-uri states:

3. Make a GET request to https://hostname/.well-known/matrix/client. 1. If the returned status code is 404, then IGNORE.

This means that chooj shouldn't rely on the fetch() for this file to be successful. Instead, it should fall back to the specified homeserver address as the base URL. I think this fall back should be done for all errors, not just 404.

The same goes for the well_known property of the login info: https://spec.matrix.org/latest/client-server-api/#post_matrixclientv3login states that it is optional:

Optional client configuration provided by the server. If present, clients SHOULD use the provided object to reconfigure themselves, optionally validating the URLs within. This object takes the same form as the one returned from .well-known autodiscovery.

[pinusc]

The well_known property of login info is particularly insidious. I had configured my server to serve a .well-known (which should be unnecessary), and chooj appeared to let me successfully log-in but couldn't load chats and had me wait indefinitely, because chooj internally sets the homeserver url from the well_known property of the first successful login. If that property is not returned, then chooj fails to login silently (well it prints a crypting exception to console)

It goes without saying that the homeserver url should be obtained differently. Ideally the flow should be:

• Obtain server name from user, say example.com
• Query https://example.com/.well-known/matrix/client
• If 404 (or anything other than 200), then set homeserver URL to https://example.com
• If 200 and non-empty, set it to whatever it returns

Regardless of the above, then:

• If client login response contains a well_known property, then use it and override the previously set homeserver URL

By the way, the "workaround" as a synapse server admin should be to have the following config:

serve_server_wellknown: true
public_baseurl: https://matrix.example.com

This ensures the server actually returns the well_known property upon login