proposal for an 'appstart' protocol

[Bruno Haible]

Egmont Koblinger wrote:
> This (opening a text file at a particular line, maybe column as well)
> is the only feature missing from the hyperlink protocol that users are
> asking for.

José and I are asking for (C) and (D). (C) is a major feature for GNU
poke, and (D) will be a major feature for GNU gettext. (C) and (D)
cannot be retrofitted into a framework that allows only to open files
or browser windows.

> this xdg mailing list is the right place to address this. The desktop
> file should be extended to support a line offset

It's not always a line number:
  - In the case of an audio or video file, it's a time point.
  - In the case of a PO file, it's a hash sum of the English msgid.

> page number within a doc/pdf

Good point. Yes, In PDF files it should be the page numbers.

> > When the hostname is equal to the machine's gethostname(), the
> > application should be started on that machine, without using network
> > protocols.
> 
> And when the hostname is different... Trying to connect to that
> hostname is potentially highly problematic. ...

The case with the remote machine is a relatively infrequent case. I'm
not religious about this one.

If you don't like the idea of starting an app from a different machine,
we can specify that

  If the host name in the URL does not match the host name of the
  current machine, the consequences are undefined.

Then the implementation may always deny this case.

> Your proposal opens up the door for someone to inject a link into my
> terminal which, should I ctrl+click on it, would locally wipe out my
> files, or upload my potentially sensitive/confidential data to the
> attacker's site. Such design is unacceptable.

You're arguing against something different than what I proposed.
I proposed:

  It is recommended that starting such an application does not make
  (possibly undesired) side effects.

Bruno