When I’m not on forum duty or handling openSUSE-related contributions, I try to improve my code contributions to KDE, even though I’m by no means an experienced programmer (I program all day long in Python, but I’m still a biologist after all). For the upcoming 4.10 release I’ve been polishing up Python 3 support. As you may know, Python 3 isn’t the standard in many distributions (Arch Linux excluded), but despite the slow start, it is slowly gaining steam.

In one of my previous blog posts I dealt with [tagging files and resources with Nepomuk]({{ site.url }}/2010/10/pykde4-tag-and-annotate-files-using-nepomuk). But Nepomuk is not only about storing metadata, it is also about retrieving and _interrogating _data. Normally, this would mean querying the metadata database directly, using queries written in SPARQL. But this is not intuitive, can be inefficient (if you do things the wrong way) and error prone (oops, I messed up a parameter!

One of the greatest strengths of KDE is undoubtedly the asynchronous and network-transparent I/O access, employed by the so-called “I/O” slaves, part of the KIO class. If you are developing an application that requires file or network access, those classes make things incredibly simple to do, and they don’t freeze your GUI when you are in the middle of a process. In this post I’ll show how to use KIO to retrieve files from network resources using PyKDE4.

With my brand-new SVN account, I just committed some code to kdeexamples, KDE’s example code module. In particular, I committed a simple example which shows how to use KConfigXT via PyKDE4, a simplified version of [what I wrote about here]({{ site.url }}/2009/10/howto-kconfigxt-with-pykde4). As most of KDE is C++, and the Python API docs are translated directly from the C++ API docs, it is essential to have good examples to help newcomers learn faster.

A while ago I presented [“danbooru2nepomuk”]({{ site.url }}/2009/10/danbooru2nepomuk-a-nepomuk-tagger-for-danbooru-images), a small program to tag images coming from Danbooru-based image boards. Today I want to present the evolution of that program, that is a PyKDE4 client for those boards.

If you read around the KDE Techbase, or if you develop KDE applications, you may have heard about KDE’s KConfigXT. This is an extension of KDE’s KConfig, and can be used to generate nice configure dialogs with multiple pages with minimal effort, also taking care of saving and applying settings. In short, something really neat! But there are problems when using it with interpreted language bindings (such as PyKDE, which is the one I use):

• KConfigXT requires an XML file and an INI-like file to be compiled by kconfig_compiler in order to produce C++ files
• There is no such a tool (at least to my knowledge) that does the same job for bindings

So what to do? Either give up on the niceness of KConfigXT, or work around the issue. I chose the latter.