Josef Spillner

Please introduce yourself and your role in KDE.

Hi, I'm Josef Spillner, a computer sciences student from Dresden in Germany. About 6 years ago I saw KDE for the first time, and some months afterwards the first application written by myself appeared on my desktop. It was a simple KTMainWindow which controlled a voxel-space flight simulation on top of kdesktop. Needless to say it was horribly slow. But I've been writing KDE games ever since.

What is Get Hot New Stuff and KNewStuff?

The GHNS concept describes a way to let users share their digital creations. For example, user A is using a spreadsheet application and modifies a template which comes with it. This template can then be uploaded to a server, and eventually be downloaded by user B by checking the contents of the "Get Hot New Stuff" download dialogue. In the context of companies, documents can be distributed to all employees, and in the context of the internet, a community sharing framework is built on top of all this.

The KNewStuff library is the KDE implementation for checking which file providers support the requested data type, and which files are available, including their version, popularity and preview information. Files can be up- and downloaded, digitally signed, uncompressed on the fly and more.

Where are they in use today?

Inside KDE CVS, we have Quanta+, KOrganizer, several Edutainment apps and the desktop configuration as our patient and proud users. Outside of KDE CVS, a bunch of games of the GGZ Gaming Zone project uses KNewStuff to keep levels and themes current, and the move of the library to kdelibs should encourage more projects to follow this example.

Can you give us a brief technical overview of how GHNS works?

Each application can decide for itself whether it wants upload or download or both of them, and which file providers should be used for these tasks. The providers can be configured on the server side so a move or scheduled outage won't harm any users.

A download task would check for all the available files for each provider, and compare their versions with the locally installed ones, which appears as green (already installed) or yellow (installed but can be updated) signs to the user.

After the installation, a post-install script might be run, which can of course include a DCOP call so the application can be notified. There are ready-to-run KNewStuff classes available as part of kdelibs (KNewStuffGeneric and KNewStuffSecure), but for more complex tasks it is possible to subclass KNewStuff.

Where did you come up with the idea for GHNS?

I didn't :-)

To be fair, I first implemented level sharing in 2001 or so, but the direct ancestors to the current library were the "Hot New Stuff" download in KOrganizer and the KDEShare library in kdenonbeta, both of which were inspired by Torsten Rahn of kde-artist fame, at LinuxTag 2002.

Most of the integration work was done at the KDE Kastle conference one year later.

Where would you like to see GHNS used?

One candidate would be KOffice. Another one suggested already is KDevelop with its templates, which can easily get out of date on the target systems. And games. All KDE games should be extensible and be flexible enough to handle data added at runtime.

Has there been any interest from other desktops to implement GHNS?

Sporadically yes, but I'm not yet aware of any actual implementation. It would really increase the acceptance and the usefulness - think about an artist whipping up a nice design in Gimp, uploading it, and voilą the users getting it onto the desktops.

There is however a (highly configurable) SDL implementation written in Python, and a custom in-game download dialogue patch written in C. Using a decent XML library makes it easy to add other GUI frontends, but this has yet to be done.

Have you considered hosting on freedesktop.org?

Yes I have. The legitimation of freedesktop.org standards always comes from previous usage, and with KNewStuff we have a well-working example. So I'd see this as one of the goals of the near future. The usage in GNOME/Gtk+ will likely depend on such a move.

Do you have any plans for KDE 4?

Sure, the README.knewstuff file is full of them, as is the patches/ directory in KStuff CVS. First, there are always small nitpicks, like the ability to configure this or configure that, without breaking the ABI. Second, there should be tighter integration with the KDE privacy framework. Finally, the management of installed data could be eased, without however converting KNewStuff into a full package installer. But there are also others hacking on the library, so more features are to be expected.

Nice name, how long did you spend thinking that up?

The name was also adopted by me, but at least I defended it rigorously :-) Seriously, there were discussions about how it could affect users negatively, but no one came up with a better idea, and we managed to hide the name from the users who do not want to see it.

A nice technical solution for a non-technical problem.

References

1. KNewStuff API documentation

2. KNewStuff and KNewStuffSecure tutorials

3. GHNS backend reference implementation ("Hotstuff")

4. "KDE: Conquer your networks", talk given at the 5th Fórum Internacional Software Livre 2004

5. "The Dynamic Desktop", talk given at the KDE Contributors Conference 2003 "Kastle"

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