Add custom well-known

[Vetchu]

Fixes #8739

I think I did correct tests, but please recheck. I'm not sure if this is the way that is desired by the matrix maintainers - I'm open to feedback.

Signed-off-by: Jacek Kusnierz jacek.kusnierz@tum.de

[dklimpel]

Can you add some documentation to synapse/docs/usage/configuration/config_documentation.md?

[DMRobertson]

Thanks for this. I think my comments can broadly be summarised as "let's make sure users can't misconfigure things">

[DMRobertson]

Getting there!

[Vetchu]

One thing that I'm unsure of is, whether extra_well_known_content can be served without any other property in place. Should it work only if public_baseurl is declared or should it be treated independently?

[Vetchu]

I added two test cases to illustrate my point - only public_baseurl and serve_server_wellknown make the server return well_known. Should extra_well_known_content make the server return .well-known as well?

[DMRobertson]

One thing that I'm unsure of is, whether extra_well_known_content can be served without any other property in place. Should it work only if public_baseurl is declared or should it be treated independently?

Good question. The spec says that the well-known response must contain the base url (as m.homeserver). But the public_baseurl defaults to the server_name if it's not provided:

synapse/synapse/config/server.py

Lines 281 to 284 in 28989cb

	public_baseurl = config.get("public_baseurl")
	if public_baseurl is None:
	public_baseurl = f"https://{self.server_name}/"
	logger.info("Using default public_baseurl %s", public_baseurl)

Therefore we should be safe to include the custom content as-is.

[DMRobertson]

I'm surprised these tests pass as written.

• override_config makes additions to the default_config; fields that aren't mentioned don't get changed
• a public_baseurl will be set based on the server_name from default_config (see also - Add custom well-known #13035 (comment))

[DMRobertson]

Ahhh. We only actually serve well-known if a public_baseurl is explicitly set:

synapse/synapse/config/server.py

Lines 273 to 289 in e87b7b3

	# For the sake of backwards compatibility with existing installations, this is
	# True if public_baseurl is specified explicitly, and otherwise False. (The
	# reasoning here is that we have no way of knowing that the default
	# public_baseurl is actually correct for existing installations - many things
	# will not work correctly, but that's (probably?) better than sending clients
	# to a completely broken URL.
	self.serve_client_wellknown = False
	public_baseurl = config.get("public_baseurl")
	if public_baseurl is None:
	public_baseurl = f"https://{self.server_name}/"
	logger.info("Using default public_baseurl %s", public_baseurl)
	else:
	self.serve_client_wellknown = True
	if public_baseurl[-1] != "/":
	public_baseurl += "/"
	self.public_baseurl = public_baseurl

[DMRobertson]

I don't think these tests add much compared to test_client_well_known_no_public_baseurl (since that is the condition). Can you remove these please?

[DMRobertson]

Thanks, LGTM! I'm going to ask another Synapse team member to take a quick look to sanity check my thinking.

[DMRobertson]

Many thanks all!

[rwjack]

Okay, now we can remove the .well-known/matrix/client entries from our nginx servers, but what about .well-known/matrix/server?

[DMRobertson]

Okay, now we can remove the .well-known/matrix/client entries from our nginx servers, but what about .well-known/matrix/server?

If you want Synapse to serve the server well-known response, see the serve_server_wellknown config option.

If you want to add additional fields to the well-known server response: that isn't mentioned in the spec (unlike the well-known client) so we'd like to understand the use case---please open a new issue if so.

[rwjack]

For client, I use the following data:

m.homeserver
m.identity_server
im.vector.riot.jitsi

As for server, I use the following data:

m.server

Perhaps I didn't understand correctly, but just making sure, can all of the above fields be covered with serve_server_wellknown?

[DMRobertson]

can all of the above fields be covered with serve_server_wellknown?

No.

• serve_server_wellknown covers m.server (see the docs) only.
• If a public_baseurl is set in the config, then m.homeserver will be served.
• If a public_baseurl and default_identity_server are both set in config , then m.identity_server will be served.
• This PR adds a mechanism which allows you to serve im.vector.riot.jitsi in the client response.

[rwjack]

Awesome, so everything can be covered, not in a way I understood though, but you explained it perfectly. Thanks!