Ubuntu Wiki

Please check the status of this specification in Launchpad before editing it. If it is Approved, contact the Assignee or another knowledgeable person before making changes.

• Launchpad Entry: preferred-applications

• Packages affected: gnome-control-center, gnome-volume-manager

Summary

Selecting preferred applications is more difficult than it should be. One should be able to say you prefer Abiword and have all filetypes automatically changed. If I prefer F-Spot to G-Thumb, all filetypes *and* the camera importer should be changed. If I change my prefered webbrowser, the panel launcher should change automatically.

List of possible applications should include those in the archive as well, selecting one installs it and marks it preferred.

Release Note

TBD

Rationale

Switching the default application is currently not very discoverable. It involes right-click, Properties/Open with. Switching the for something like a camera is a problem too, its under "removalble devices" and it requires the user to change the commandline arguments (with no go back to default setting).

Use Cases

• Bob wants to change his default from gthumb to f-spot
• Alice wants to use epiphany instead of firefox by default

Design

We need:

• Launchers should support "prefered application" in addition to the current "Command". This way the user can have a web-browser launcher that automatically changes if the preference changes.
• The prefered apps dialog should list available applications as well as installed ones. It should install them if the user selects them (integrate add/remove and the mime-types, tags somehow)

• The "Removable Drives/Media" capplet should be merged into prefered applications (to the extend that makes sense). The prefered applications should have a methods (desktop file?) to tell if/what it supports for removable media (e.g. ImportFromCamera commandline). It should be possible to use some combobox instead of the current (scary) commandline options.

It should be possible to set the default application via right-click on a generic-app launcher.

The list of generic applications includes:

• web browser
• mail client
• instant messanger
• image viewer
• text editor
• music player
• video player
• terminal emulator

The prefered application is selected by looking into some gconf/dconf/file based configuration.

A possible implementation would use dbus activation to launch the application (e.g. org.gnome.Epiphany). Each application would implement a standard interface (eg. each browser provides a openURL() call etc). Mime-type and removalable media handling would be implemented the same way. A standard interface like "importFotos()" would be provided by the applications. The problem with this approach is that the applications would need to querried (started) to get information like name and icon (the icon should change when the default web-browser changes). There are some plan from upstream to go into this dbus direction.

A alternative approach would be to change:

• the default applications to store a desktop file name in e.g. /desktop/gnome/applications/browser instead of the current "exec" configuration
• the panel to have a new launcher type that says "prefered application" and that uses the gconf information to figure out what launcher to display

• the desktop file gets extended to provide information about things like "ImportFotos=gthumb-hal-import %s" etc so that switching can automatically switch the gnome-volume-manager specific commands.

The method to be used will be discussed with upstream.

Once this spec is implemented, the default application launchers in the ubuntu panel config should be switched over to this new method.

UI Changes

TBD

Test/Demo Plan

TBD

Outstanding Issues

• Any relevant existing fd.o specs?
• Should we submit this as an fd.o spec? If so plan to write it
• Merged Preferred Applications and Removable Media prefs

BoF agenda and discussion

Managing debian alternatives (update-alternatives and friends) was discussed and discarded because it would require root and is not portable.

CategorySpec