3kbo

Recently, while developing on a Windows 2000 machine I got the following error when trying to commit some code into a subversion repository located on a Solaris server.

svn: Commit failed (details follow):
svn: MKACTIVITY of ‘/repos/xxxxx’: 403 Forbidden

Took awhile to find the cause of the problem. It turns out that I had accidentally signed in the with an upper case in my username, which was fine for checking out the code but when trying to check in there was no matching username on Solaris.

Trouble was there was no visible indication that this was the problem. The cause was only revealed by looking at the server log.

Even then the fix was not straight forward, since I was using Eclipse and the Subclipse plugin, with no obvious way to reset the username and password.

So I checked out the repository again via the svn command line, explicitly setting my username.

(See: http://www.tigris.org/nonav/scdocs/ddUsingSVN_command-line.html ).

I made a change in the new repository and committed the change, again using the command line. This time the commit worked.

When I refreshed the project within Eclipse I could now see that the change I had just made was registered against my correct username while there were other outstanding changes registered against my incorrect username.

Funny thing was that as I made changes within Eclipse the new changes were now recorded against my correct username and I could successfully commit from within Eclipse.

It seems that the explicit check out of the repository to a different location had magically fix my username problem.

Last week-end I installed ActiveRDF on my Mac OS X Powerbook, together with the Sparql, RDFLite and Redland adapters. Ideally I am working towards setting up an environment that allows me to build RESTful Semantic Web Applications that support reasoning over RDF data and implement a SPARQL query end point. Support for OpenID authentication, integrated with FOAF, is also at the top of the list.

On the Powerbook I could also install the ActiverRDF adapters for Sesame and Jena to give me the functionality that I am after but that only works in my development environment. Sesame and Jena are Java based. When it comes to deploying an application onto the web my options are currently more limited. 3kbo is deployed into hosted environment which supports PHP, Python, Ruby and Ruby On Rails and PERL, but no Java. (There is C/C++, limited to my local user account.)

Currently there are two PHP SPARQL implementations, ARC and RAP. RAP also provides a reasoning engine InfModel, with support for owl:sameAs and owl:inverseOf.

So at this stage the architecture that is emerging is an ActiveRDF RESTful Ruby On Rails application that uses RAP as the triple store, SPARQL query engine and reasoning engine. To integrate Rails with PHP I am planning to implement a RESTful PHP interface that acts as a facade to RAP.