[packagekit] [Ubuntu-appstore-developers] D-Bus API for Click Packages (PackageKit/AptDaemon)

[Sebastian Heinlein]

Am Mittwoch, den 03.07.2013, 15:53 +0200 schrieb Matthias Klumpp:

> P.S: @Sebastian: OT question: Why does Ubuntu need sessioninstaller,
> if they could simply use gnome-packagekit-session instead? (just out
> of curiousity)

Again a little bit of history:
Sessioninstaller was created before aptdaemon gained PackageKit system
interface support. The initial assumption (before GObject introspection
was introduced) was that third party clients would use the session
interface only. So sessioninstaller was an effort to get PackageKit used
in Ubuntu at all. The system interface was in the first run made for
"advanced" software management tools, which we already had in place for
Ubuntu (software-center and update-manager).

But next to the historical reason there is also a technical one:
Sessioninstaller provides some unique features compared to
gnome-packagekit-session. It takes more information into account by
querying the APT and xapian cache directly. E.g. it can report to the
user which of the requested codecs will be handled by which package. If
there is a package which could handle all requested codecs. Which
package provides the best support for the searched codec. So the best
codec packages are already pre-selected by sessioninstaller. It contains
an information about potential patent encumbered code. It makes use of
the APT xapian index with the added application data of software-center
to show applications instead of packages.

P.S. I will reply to the rest of your message later.