Gigabytes’ Blog

Hello again! It’s time for the last (maybe) blog post about my gsoc.

My work on the GSoC project in the last weeks has focused on the integration of the new authorization library with the rest of kde. You can find all the code in the subversion at branches/work/kdelibs-libkauth and kdebase-libkauth.

A brief explaination of what I’ve done follows.

First of all, two new classes has been added to KDEUI. They’re KAuthorizedButton and KAuthorizedAction. The first is a KPushButton subclass that automatically handles authorization. If you need to execute a privileged action when the user clicks on a button you can use this one. For example:

KAuthorizedButton *button = new KAuthorizedButton(KStandardGuiItem::apply());
button->setAuthAction("org.kde.auth.example.apply");
connect(button, SIGNAL(authorized(KAuth::Action)), this, SLOT(applyClicked()));

This way the slot will be executed when the user clicks the button but only if it’s authorized to execute the action. Additionally, if the action requires authorization, the user will see a different icon (a key, a lock, or something like that. currently it’s the “dialog-password” icon, what do you suggest?). The KAuthorizedAction class works exactly the same, but it’s a KAction subclass for use in toolbars and menus.

The next step is the integration of the authorization library with the kde configuration modules API. Specifically, I’ve added some trivial APIs to the KCModule class to allow a module to declare that its save() method requires authorization to be executed. This way, System Settings and kcmshell can now handle authorization of the module’s save action. As part of my work I’ve ported the date/time kcm module to the new library. Its code already followed the caller/helper pattern, but authorization used kdesu and data was passed using commandline arguments. The new code saves some lines of code and seems a bit cleaner.

The method I’ve added to KCModule are setNeedsAuthorization() and setAuthAction() (and getters). A module calls the first method to tell the world that its save() method requires authorization. The second allows it to tell which action has to be authorized. Actually, needsAuthorization() will return true if a valid action has been set using setAuthAction(). Alternatively, a default action name is set if you only call setNeedsAuthorization(true). The default name will be “org.kde.kcontrol.name.save” where “name” is the KAboutData::appName() return value, so if you rely on this, your module have to provide a suitable KAboutData object. Note that in this case, setNeedsAuthorization() will also set the default helper ID to “org.kde.kcontrol.name” using KAuth::Action::setHelperID().

Writing a kcmodule that uses the new library is not so different from a stand-alone application. The only other thing to do is to call setNeedsAuthorization() or setAuthAction() in the constructor. Note that this applies to the action performed when the user clicks on Apply/Ok. If your module does something else (like the KDM module that installs themes), you’ll have to handle it yourself.

Now you can see how the date/time module looks like in the new System Settings app, with the policykit authorization dialog already opened (you can notice the different icon on the Apply button):

KDE Date/Time configuration module ported to libkauth

The different icon also appears in the close dialog:

The Apply/Discard/Cancel dialog when the Apply action requires authorization

Of course the icon the the standard Apply icon if the action doesn’t need authorization…

That’s all by now. In the near future, after the gsoc end, the new library will be moved into kdelibs and will be available to be used by everyone. I’ll help in its integration with the rest of KDE including KIO and GHNS, other kcm modules and applications such as ksysguard, so this could not be my last blog post on this topic, after all…

Bye bye!!

Generale, Unix world Planet KDE