Also I want to highlight this excellent comment by Yumechi about fingerprinting and de-anonymization risks.

https://socialhub.activitypub.rocks/t/fep-07d7-a-custom-url-scheme-and-web-based-protocol-handlers-for-linking-to-activitypub-resources/3588/53

@SoniEx2@chaos.social @silverpill@mitra.social @julian@community.nodebb.org @rimu@piefed.social

Glad to see more people having this idea! The problems we ran into were in helping the browser understand the address and know where to forward. Each server implements lookup routes differently, so there's not necessarily a generic path that you can trust is available on https on the person's home server, even if you know their home server origin. So in some ways the feature should be offered by your home server software, maybe offering a website that does the handler registration to its known lookup/redirect address.

But that is limiting in a few ways. It's a lot of extra steps for each person to do (browsers' default UI for registering protocols is not obvious or easy). It doesn't carry over to different devices, and if you have more than one home server in some way, you are back dealing with that not-great browser UI to pick which handler you want.

In general people are more accustomed to registering protocols to apps they have installed, especially phone apps. It's much easier to register them there and you don't have to have approval flow UI, but taking that approach moves this whole served handler route out of the backend again, so we have to start thinking more along the lines of web+ap-compatible servers that handler clients know how to call or bounce to.

@julian@community.nodebb.org @silverpill@mitra.social @SoniEx2@chaos.social @rimu@piefed.social