webfinger shenanigans

It turns out that creating a webfinger response at the .well-known path is really easy!

What is webfinger? Well, it’s one of several open source technologies that underly the fediverse.

WebFinger is a protocol specified by the Internet Engineering Task Force IETF that allows for discovery of information about people and things identified by a URI. Information about a person might be discovered via an acct: URI, for example, which is a URI that looks like an email address. –Wikipedia

Just like its predecessor, finger, it lets you poke at an endpoint and get back some basic info.

finger tomasino@gopher.black

alexlehm suggested that we implement this on cosmic.voyage so that we can use our accounts there conveniently around the fediverse. Normally users can find me at @tomasino@tilde.zone, but they may not know that. Some may know me from my authorship on cosmic.voyage, or maybe my time on tilde.team. Wouldn’t it be nice if anyone can insert my addresses at those places and just end up with the correct account?

Well, alexlehm recommended this page to get started. It had lots of great info about how to structure a webfinger response, but it all boils down to this:

A request will come in to the path /.well-known/webfinger?resource=acct:<username>@<domain>. It needs to respond with a json file with a mime type of application/jrd+json. That json file has a bunch of info in it, but the easiest thing to do is just copy it from your fediverse account!

curl https://<domain>/.well-known/webfinger?resource=acct:<username>@<domain>

So that’s what I’m doing. Cosmic’s web server is an express app running a thin layer of HTML and styling on top of the core gopher site that powers everything. That’s not really important, though. It just needs something to handle that well-known URL and point it to the json files for each user if they exist.

If you want to do that yourself, I recommend the solution that ben did. Toss a PHP file at that location, strip any of your server-specific lingo, and check if the user has the webfinger json file at some convenient location.

We’ve settled on using ~/.webfinger.json, but maybe you have other opinions.

I even wrote a quick shell script that asks for a user’s fedi account and does the fetching for them. Feel free to grab it and modify for your own needs.

In summary

You can now find me on fedi by using @tomasino@cosmic.voyage or @tomasino@tilde.team or @tomasino@fuckup.club. It’ll all redirect to my tilde.zone account nicely. :)

EDIT

For private systems that you don’t share with others, you may want to just serve a single webfinger file no matter what the query is. Everything at the tomasino.org domain should point to me, right? Well, that site is a static one, so php solutions are out. Instead I just made a quick nginx rule like so:

  location /.well-known/webfinger {
    add_header Content-Type application/jrd+json;
    alias /var/www/www.tomasino.org/.well-known/webfinger.json;
  }