Desktop Entry Standard: Path key

[Vincent Untz]

Le jeudi 26 juin 2008, à 10:53 -0700, Brian J. Tarricone a écrit :
> David Faure wrote:
> > http://bugs.kde.org/show_bug.cgi?id=164068 brings me to posting this mail here.
> > 
> > As far as I can see there is no support for expanding environment variables in the desktop entry standard?
> > This is a problem for the "roaming user" feature: a user should be able to use software that creates
> > config files and desktop files, and then move his home somewhere else and the software should keep working.
> > Is there a solution for this problem (especially for desktop files) in other environments at the moment?
> > 
> > In KDE we support Key[$e]=$HOME/Documents  where the $e modifier means "expand env vars".
> > This works fine in kconfig files, but for the Path key of desktop files, this is a violation of the desktop
> > entry standard; more precisely it doesn't work in other environments.
> > 
> > Assuming a more complete specification of this [$e] thing (I'd have to ask our KConfig guys),
> > is this a solution that would seem acceptable for the Desktop Entry Standard?
> > 
> > In KDE 3 we would simply use env vars and expand env vars in the Path key, without requiring [$e],
> > but that was even more broken and non-interoperable, and we decided to be more strict about
> > this stuff in KDE 4, so nowadays [$e] is required for this behavior.
> 
> I'd definitely be interested in adding something like this to Xfce's 
> menu implementation, among other things.  It seems people (well, non-KDE 
> people) around here have been pretty resistant to the Key[x] modifier 
> type thing for some reason, though.

Don't know if it was ever proposed for inclusion, but I can see why
there's some resistance: it looks like a hack because it's done in a way
that extends the format while staying compatible with it.

> Personally I'd be happy with just saying that we should expand all env 
> vars always in keys where it makes sense, but obviously there are 
> backwards-compat issues with this (even though most people probably 
> won't have '$' symbols in their filenames).

I'm not opposed to expanding env vars, although it needs some thoughts.
Is it always secure to do so, for example? What should be done when the
environment variable is not set? etc.

Backwards compatibility is also an issue, indeed. That's one of the good
things with [$e], I guess. Another approach would be to define a new
group [XDG env vars] where keys can overload keys from [Desktop Entry]
and use env vars -- although if we start adding groups for specific
features, it might become a big mess at some point...

Vincent

-- 
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