Vazaar Project Blog

After months of improving my skills with Python and PyGTK and reading documents about semantic web and its integration with Desktops Interfaces (like GNOME or KDE) a lot of improvements have been made in Vazaar. This is an overview of the current state of development.

The presentation layer, the GUI, is more difficult to develop than I’ve ever thought. Althought the concept is simple: given any kind of data, transform them into triples (subject, predicate, object) and operate with them, the time consumed to create an infrastructure around the program has been very high.

As resources can be added at any time, I had to develop a system of queues (qIn and qOut). Furthermore, I had to deal with very high responsiveness times. It’s very annoying when the GUI gets frozen because the kernel is working in other stuff. So I had to implement threads (one thread for the kernel and another thread for the GUI). Along the way, I’ve found a lot of code (see source code in Launchpad) which has helped me to carry on.

In some way, I would like to forget these kind of glitches when I’m developing a Desktop application (not a kernel module). Maybe I’ve learnt something about gtk threads but nothing interesting for this project. Never mind…

I’m still reading some documents and asking about how to create a data model around NEPOMUK. By using the semantic web paradigm things change a lot. There are no database records or tables. Instead there are thousands (or hundreds of thousands) of triples.

But it looks easiest than I thought, at the moment.

Everything is a resource (even collections). A resource has a unique identifier (UUID objects according to RFC 4122). Every resource belong to a unique Nepomuk class. They are a small subset of classes with their properties. Examples of Nepomuk classes are:

• nfo:Feed
• nfo:Website
• nfo:RemoteDataObject
• nfo:Image
• nfo:Audio
• nfo:Clipboard (this class doesn’t belong to NFO but I need it until I find a smart solution for copypaste operations).

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Nine months after my last post, I’ve got a new home for Vazaar.

It lives now at https://launchpad.net/vazaar

I want to use the infrastructure provided by Ubuntu to accelerate the development and subsequent integration into
Ubuntu or Debian repositories.

Hope it be useful for everybody.

I don’t know what is going on but my svn repository hosted in Dreamhost is gone  :-(

patience

Edit Saturday, September 06 2008:

Well, finally, I know what happend. My hosting company deciced to upgrade their 32bits Debian OS to 64bits and it failed. A lot. I haven’t lost anything but the svn is misconfigurated. So I’ve changed my repository to google code.

Please, update your bookmarks. You can access to the repository here:
svn checkout http://vazaar.googlecode.com/svn/trunk/ vazaar-read-only

or check this page:

http://code.google.com/p/vazaar/

Sorry about that

Voy camino de ser el blogger más improductivo de toda la red. Creo que leo más que escribo. Intentaré remediarlo. De momento, os dejo esta perla que me he encontrado:

Dublin Core Metadata Glossary

Final Draft

The Dublin Core Metadata Glossary is a collaborative effort of the User Guide Committee with special thanks to Gail Clement & Pete Winn, whose original glossary was a basis for this version. Terms included in this glossary are based on Dublin Core documents, presentations at DC conferences, and discussions on the DC General listserv. We welcome comments and feedback regarding additions, deletions or changes to the terms and/or definitions found below.For related links, including the guide itself, see this site’s home page.

The glossary was last updated on 02/24/2001

Aunque data del 2001 no me consta que las definiciones cambién de lustro en lustro. Todo un manjar para comprender los conceptos de la web semántica.

Editado (jueves, 28 de febrero de 2008 02:16)

He encontrado el glosario actualizado (23 April 2004) en la propia página de Dublin Core

Bueno, después de casi dos meses, puedo decir que he avanzado un poco más. Para no quemarme, aburrirme o morir en el intento voy alternando entre la programación de la interfaz gráfica y el motor de la aplicación.

La parte gráfica de momento es un laboratorio. Me limito a saber leer correctamente los recursos de la base de datos semántica, interpretar lo que me duvuelven las consultas y presentarlo chapuceramente al usuario. Voy a tener que buscar o hacerme bastantes widgets a medida. De momento me he creado una nube basada en una Gtk.Table donde represento los datos y sus frecuencias. Bastante útil, por cierto.

En relación al motor de la aplicación hay tres grandes cambios:

- Para no bloquear la parte gráfica estoy implementando hilos. Deberían llamarse líos.
- He adoptado el uso de colas para todas las peticiones de trabajo.
- Vazaar dispone de un sistema de plugins.
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