Would XFCE consider adopting AppData?

Richard Hughes hughsient at gmail.com
Wed May 21 11:43:03 CEST 2014

On 21 May 2014 09:57, Simon Steinbeiß <simon at xfce.org> wrote:
> I've just pushed a branch for Parole[1] which adds basic AppData for it.

Great, thanks! I'll cc in Matthias who's the main guy behind AppStream.

>whether you could review it

Some initial points:

* http://http:// in the first screenshot
* You want to use <_p> and </_p> if you're going to use intltool to
translate those files. The underscore just marks the tags for
translation and means they end up in the .po files.
* Are those screenshots both 16:9 aspect ratio?
* <release version="0.6.1" timestamp="20140330"> -- the timestamp is
supposed to be a UNIX epoch
* The descriptions of the releases are supposed to be translated prose
the users can understand, so less of "<p>Latest stable release, see:
http://some-obscure-URL</p>" more of "<_p>This release brings
improvements to the MPRIS plugin, fixes a few crashers when running on
ARM12 hardware and adds the ability to transcode FLV files.</_p>"

If you use appdata-validate --strict from the appdata-tools project
you can catch some of these problems.

> How do you guys handle that? Or shall we just point to a git-commit instead?

This is for mere-mortal users, things like git URLs are black magic :)
-- Aim for the non-technical user -- I always write this kind of stuff
with my dad in mind, i.e. he's not an idiot and knows how to use an
application, but he doesn't care about sonames being bumped and what
internal interfaces are doing.

> Also, I presume the screenshots should be on a server that is not going away anytime soon, right? Or are they pulled into some centralized server anyway?

Right. In gnome we just point that at the gitweb server we have. What
distros are supposed to do (and what Fedora does) is download the
images *once* to a cache and then only re-download them if the URL
changes. Then in the case of Fedora we convert all the screenshots to
PNG, pad with alpha to the 16:9 aspect then upload to
http://alt.fedoraproject.org/pub/alt/screenshots/ -- it wouldn't be
fair to hit the upstream project with thousands of new requests for
large images, and could also be a privacy issue.

> Last but not least (and you'll notice that when reviewing anyway), there are some differences between these two specifications
>  * http://www.freedesktop.org/software/appstream/docs/sect-Metadata-Application.html
>  * http://people.freedesktop.org/~hughsient/appdata/
> Which one is accurate (and why are they different in the first place)?

The second is the "old" specification, which is what I've been pushing
for a couple of years now. Slowly the former is superseding the old
format, but any applications that don't understand the new schema only
support the old one. I've worked with Matthias on the new spec, so
that's why it's mostly a super-set of what I did originally. When
applications like GNOME Software 3.10.x are EOL then I'll retire my
page and point everyone to the new spec. The old spec I'll basically
have to support forever, which is fine. Given that XFCE doesn't have
any legacy apps to support, I'd say go for the new format rather than
the old one. From GNOME 3.12 onwards we support either format when
parsing and generating distro metadata.


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