Renaming `at:alternate` metadata to align semantics with `rel=`

[essentialrandom.bsky.social]

Continuing the discussion from Connecting records, web pages and apps.

As I mentioned:

@essentialrandom.bsky.social

rel="alternate" is about alternate representation of a specific document, not “alternative records the page is associated with”. If Bluesky app is adopting this, we may want to fix that part of the spec up before that becomes a point of confusion we carry forever.

Thread reactions

There seemed broad support in the original thread for fixing this, so I collected what people said:

@fabricatedtechnobabble.com

Caution on at:alternate—pointing at:alternate at a parent publication or comment thread breaks HTML alternate semantics (and risks clients redirecting an article URL to the blog homepage or a comment thread).

@esb.lol

This is a good shout. I think @fabricatedtechnobabble.com is saying something similar. Perhaps something more like at:associated is a better name for this?

There is also this comment by @snarfed.org…

@snarfed.org

The web and the fediverse already have good, structured ways to do this. You all have already discussed the web side, rel=alternate and rel=canonical links, and the fediverse reuses those with its FEP-fffd proxy links, both of which we use in Bridgy Fed. As an example, here’s the proxy link in the bridged ActivityPub AS2 object for this Bluesky post:

"url": [
  ...,
  {
    "href": "at://did:plc:xgvzy7ni6ig6ievcbls5jaxe/app.bsky.feed.post/3mxhjydoiwk2i",
    "rel": "canonical",
    "type": "Link"
  }
]

(There’s also an optional mediaType property, which we don’t use, for the MIME type.)

…which confirms our misuse of alternate and adds:

Each Link in url with "rel": "alternate" or "rel": "canonical" is called a proxy link. Any Object with one or more proxy links is called a proxy object. The referent of a proxy link is called a proxied object, and SHOULD be considered semantically identical to the parent proxy object, modulo the limitations described in section 4.

Our choice

So! Given the resounding chorus of “pls don’t”, we should look into an…alternat(iv)e.

1. @esb.lol proposed at:associated
2. Personally I like at:related ⇒ “yes, this has a relationship to the at:canonical record; no, we don’t have a specific name that tells you what that is”

We should also discuss domain-specific relationships (comments, author), but those should IMO be their own thread and specification. Maybe they could even be namespaced or taken from another pre-existing spec!

[lemmaeof.gay]

I’m in favor of at:related!