GNOME Shell Search Provider example app

"Search providers" are the officially supported integration point for third party applications in the GNOME search system.

A search provider can conceptually be seen as the way a third party application presents itself in the context of a GNOME Shell search.

Technically, it is implemented using DBus service activation, and it works like this:

• every search provider must implement the org.gnome.Shell.SearchProvider2 DBus interface, which is documented here [1], drop a keyfile in /usr/share/gnome-shell/search-providers/ specifying the bus name and object path it will use (see src/search-example-provider.ini for an example), and have a corresponding service file for activation like any other DBus service (see src/org.gnome.SearchExample.SearchProvider.service for an example). The provider must also be associated with the "manifest" of an application installed on the system, i.e. its desktop file.
• GNOME Shell will read all the keyfiles from the former directory and keep track of the installed providers. When the user starts a search, the GetInitialResultSet() method as above will be called on each provider; DBus activation will automatically start each process if it's not running already, and ensure only one process per-provider is in use at any given time.
• information about the results will be exchanged over the wire between the Shell and the provider processes, and finally when the user selects a result, ActivateResult() will be called on the corresponding provider, which can open a window, launch or another process, or do whatever is necessary for the result to be presented to the user.

The use of a standard DBus interface and separate processes makes it very easy to implement search providers in any language offering a DBus binding, avoids any licensing issues due to linking and gives the maximum freedom to the provider implementation on how to present activated results, while keeping the overall architecture easy to use.

Upgrading To Gnome 3.20

These changes are applied on top of official repository [2].

• make the example as minimal as possible
• remove support for translation (it causes many problem and getting away from the minimal concept)
• remove g_type_init (it is deprecated now)
• remove automatic desktop file generate
• make example more object oriented by creating header files
• remove -USE_GNOME2_MACROS=1 and PKG_NAME in autogen.sh (deprecated)
• change all call back to return gboolean instead of void this cause (gnome-search-example:29658): GLib-GObject-CRITICAL **: g_object_unref: assertion 'G_IS_OBJECT (object)' failed

Contribution

Both feedbacks and contributions are appreciated. Please put any comment in repository pull-requests and I will check it ASAP.

[1] https://developer.gnome.org/shell/unstable/gdbus-org.gnome.Shell.SearchProvider2.html
[2] https://github.com/cosimoc/gnome-example-search-provider