When users are searching for software in GNOME Software it is very important to answer the the question “Is this localized in my language?” If you can only speak Swedish then an application talking just in American English is not much use at all. The way we calculate this in the AppStream builder is to look at the compiled
.mo files, breaking them apart and then using statistics to work out what locales are included.
When we’re processing distro packages we usually extract them one at a time. We first try for a gettext domain (the
.mo file name) of the distro package name, and if that’s not found then we just try and find the first .mo file in any of the locale directories. This works about 70% of the time (which is good) but fails about 30% of the time (which is bad). For xdg-app we build the application in a special prefix, along with any dependent libraries. We don’t have a distro package name for the bundle (only the application ID) and so the “first .mo file we can find” heuristic fails more often that it works. We clearly need some more information about the gettext domain from the upstream project.
AppData to the rescue. By adding this in the AppData file informs the AppStream generation code in the xdg-app builder what gettext domain to use for an application. To use this you just need to add:
<component> tag. The gettext domain is normally set in the
configure.ac file with the
GETTEXT_PACKAGE define. If you don’t have this extra data in your application then
appstream-util validate is soon going to fail, and your application isn’t going to get the language metadata and so will be lower in the search results for users using GNOME Software in a non-C locale. If your GNOME application is available in jhbuild the good news is that I’ve automatically added the
<translation> tag to 104 projects semi-automatically today. For XFCE and KDE I’m going to be sending emails to the development mailing lists tomorrow. For all other applications I’m going to be using the
<update_contact> email address set in the AppData file for another mass-emailing.
Although it seems I’m asking people to do more things again and again I can assure you that slowly we’re putting the foundations in place for an awesome software installer experience. Just today I merged in the xdg-app branch into gnome-software and so I’m hoping to have a per-user xdg-app preview available in Fedora 24. Exciting times. :)