DNS SRV entries for endpoint discovery

[azmeuk]

The discovery chapter suggests that The client first performs discovery on the user's profile URL to find the Microsub endpoint and authorization endpoint. Then endpoints should be discovered from the profile page.

Some feed aggregators (I am thinking of nextcloud-news or newspipe) would benefit from implementing microsub, but implementing a profile page just for the sake of the discoverability might feel out-of-scope (although nextcloud itself might be a good candidate to do this).

Other protocols define DNS SRV entries that can be used for discovery. For instance:

• RFC6186 for SMTP, POP and IMAP,
• RFC6764 for CalDAV and CardDAV,
• The matrix protocol defines its SRV entries.

I suggest that the microsub-spec defines DNS SRV entries as an alternative endpoint discovery method, so clients might discover the microsub endpoints just by the domain.

What do you think?

[aaronpk]

I think I'm understanding what you're asking, but I think you're coming at it from a different angle.

There's really two parts to Microsub, the discovery aspect and the actual client-to-server protocol aspect. I think you're really only interested in the client-to-server part.

The discovery part is explicitly so that a user can define which Microsub server they want to use. So it doesn't make sense for an aggregator to host profile pages because that's not a user's home page. The premise is that a user has a profile somewhere and points to an aggregator service elsewhere.

[azmeuk]

Maybe I can tell about the usecase I am thinking of to be clearer.

Say there is a website mycloud.com with a OIDC server hosted at auth.mycloud.com and a mail server hosted at mail.mycloud.com, and a microsub server hosted at feeds.mycloud.com.

In the mails world, users are only required to know their email address [email protected] and clients like thunderbird do all the dark magic so users do not need to configure anything.

Similarly, I wish users could use a microsub client by only filling the mycloud.com domain, so they would not have to know subdomains nor the full endpoint URIs like feeds.mycloud.com/microsub.

The premise is that a user has a profile somewhere and points to an aggregator service elsewhere.

Do you mean that the profile URI is expected to be given to a microsub client so it magically finds on which microsub server to connect, or do you mean that microsub cannot be used

[jalcine]

The first part! Also, it's important to note that Microsub implies a use of IndieAuth (via https://indieweb.org/Microsub-spec#Authentication_and_Authorization), which sets the idea of a profile URL being present as a normal behavior. The DNS lookup / peeking would be a bit out of the range of this.

(Originally published at: https://jacky.wtf/2022/6/Br51)