Improve follow flow with custom web protocols (web+follow:username@host.tld)

[pfefferle]

Pitch

In 2010 Mozilla wrote an article "RegisterProtocolHandler Enhancing the Federated Web".

The idea is to register a protocol handler when logged into a mastodon account:

if (typeof navigator.registerProtocolHandler === "function") {
    navigator.registerProtocolHandler("web+follow", "https://mastodon.social/authorize_interaction?uri=%s", "Follow");
}

On the profile pages, the follow button could look like:

<!-- check if browser support registerProtocolHandler -->
<a href="web+follow:username@host.tld">Follow</a>

RegisterProtocolHandler is supported by most modern browsers (except Safari but maybe Mastodon could change this). If there is a check, it should not break anything.

Motivation

Improve the "decentralized follow" flow, to feel more like a classic silo (twitter, facebook) follow.

[ClearlyClaire]

We used to register protocol handlers but stopped doing that because of a combination of it not being actually used much, and browser's UI being off-putting: #8127

[pfefferle]

Oh, so sad. I think it is Hen/Egg problem. If there is no service using it, I think it will not improve.

[SuperSandro2000]

This should be re-added but not after 5 minutes but with a button at a good place.

[SoniEx2]

👍 to having a button in a good place. I'd put it under preferences.

however, a bigger issue is that websites can't just provide a fallback handler like they can provide base URLs for anchors. see also whatwg/html#4584

[pfefferle]

@SoniEx2 you are right... the implementation is far from perfect, but I think a platform like mastodon (or the complete fediverse) would (hopefully) give some importance to the custom protocol handler and would help to improve the spec and the current browser implementations.

...but I would recommend to not use web+mastodon: ...it would be awesome to have a generic "follow" button for the fediverse! 😍

[SoniEx2]

yeah. web+activitypub: would be nice, I think.

[DarkArc]

I've added a suggestion on the Mozilla side for first party activitypub://foo@bar.com URL protocol handler support:

https://connect.mozilla.org/t5/ideas/add-user-friendly-first-party-activitypub-handle-support/idi-p/19622

[SoniEx2]

see also #19613