Re: bug-reference.el: Allow custom handlers for opening URLs

[Yuri Khan <yuri.v.khan@gmail.com>]

On Sun, 3 May 2020 at 22:25, Tassilo Horn <tsdh@gnu.org> wrote:

> Yes, that's probably even better/more generic.  But again, I wouldn't
> want to hard-code that, so I guess we'd want some `browse-url-handlers'
> in browse-url.el doing basically the same as the
> `bug-reference-url-handlers' I proposed, right?
>
> Looking at it, there're already some special handlers for mailto: and
> man: page URLs.  Should I convert those to default entries of the new
> `browse-url-handlers' alist?  (IMHO, yes.)

This is very similar to what applications on mobile systems do (both
Android and iOS). The colloquial name is “deeplinking”. Looking from
one angle, it lets you exchange links to various screens inside an
application as if they were pages on the web. From another angle, it
lets application authors to provide a generic implementation on the
web (so that desktop users are served), and substitute a more capable
implementation via an app.

Basically, an application declares to the system that it is capable of
handling URLs with this or that scheme, and/or URLs referring to this
or that domain. After that, if any application (including the system
web browser) signals an intent to open a URL that matches these
conditions, the system offers the user a choice which handler to use,
with an option to remember this choice for later occasions.