To cut to the chase, if you want to save your current sessions in KDE4 run the following command from a command line ( or put it in a script that you can call from a desktop shortcut ):
dbus-send --dest=org.kde.ksmserver /KSMServer org.kde.KSMServerInterface.saveCurrentSession
Now for how I got here in the first place:
I’ve just upgraded to Kubuntu Hardy Heron and decided to give KDE4 a go. I’ll be posting about the upgrade process and KDE4 in general over the coming days but one thing that has kept me “amused” today is the lack of a “Save Current Session” button in KDE4
Rather than have the desktop returned to how it was when I last logged out ( “Restore Previous Session” under KControl ) I like to return to a standard set of applications so I use the “Restore Manually Saved Session” option under KDE 3.5.
In KDE4 KControl there are the same options for the session manager. The snag is that there is no button anywhere to actually save the session when you want to. Thus choosing this option effectively logs you back in to a blank session. This has been reported as a bug in KDE but does not seem to be making any progress.
Flushed with my success with dcop recently I was hoping I could use it with the ksmserver object ( the session manager ) but in KDE4 dcop is not used and the dbus interface is used instead which is a bit more complicated to use.
There is a tool you can install called kdbus that does a similar job to kdcop but I found a much better tool called qdbusviewer along with a useful overview of KDE and dbus here.
To use qdbusviewer you need to install the package qt4-dev-tools then run qdbusviewer from a command line:-
sudo apt-get install qt4-dev-tools
You can use qdbusviewer to browser what objects are available and execute methods on them just like kdcop and kdbus ( but kdbus is rather slower )