Re: [Semediawiki-user] SMW and SPARQL endpoint (RAP) - part 2

[Laurent A. <la...@al...>]

For what is worth, I figured out both issues. I am stuck a little further 
down the line it seems :)

Mapping /id to the Special:URIResolver was trivial. 

My other issue turned out to be a symptom of a request time out PHP error, 
incorrectly parsed by the XML parser.

I will assume for now that I am getting time out errors because I am 
sending invalid SPARQL queries which, in return, try to bring back ALL 
triples in the store.

I will focus on finding out a simple query to test that assumption.

- Laurent

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From: "Laurent Alquier" <la...@al...>
Sent: Wednesday, July 29, 2009 3:42 AM
To: sem...@li...
Subject: Re: [Semediawiki-user] SMW and SPARQL endpoint (RAP) - part 2 

Could someone familiar with the server configuration of 
'semantic-mediawiki.org' take a look at this ?

Making progress since yesterday. I found out 'Allow Override' was turned 
off in my Apache configuration - no wonder the URL Rewrite did not work as 
intended :)

I installed a local SPARQL client (Twinkle) and tested it on queries 
against DBpedia to make sure it is working correctly.

Last step - building a SPARQL query against my triple store.

Two issues remain at the moment :

1- If I try opening the URL of the model as defined by RAP - 
http://servername/rdfapi-php/netapi/model' - I get an error about invalid 
XML (related to a font 'color=#ff0000' parameter).

It looks like it is trying to retrieve triples from the model but the error 
is telling me something is still wrong.

2- RAP defined two URLs. 

http://servername/model - for the model as stored in RAP
http://servername/id - for objects.

The idea being, the URL : 'http://servername/id/Property-3AHas_location' 
should be translated into: 'http://servername/wiki/Property:Has_location'.

For example, this is working on the SMW site with URLs on this page: 
http://semantic-mediawiki.org/wiki/SPARQL

What I am missing is how to map the object URL to enable the translation. 

In my configuration,  'http://servername/id/Property-3AHas_location'  
returns 'Page not found'.

Almost there....

- Laurent

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From: "Laurent Alquier" <la...@al...>
Sent: Tuesday, July 28, 2009 2:38 PM
To: sem...@li...
Subject: [Semediawiki-user] SMW and SPARQL endpoint (RAP) - part 2 

Hi again

I thought I would give another shot at setting up a SPARQL endpoint for my 
SMW. 

First I looked at SMW+ Jena connector. The video tutorial on the SMW+ forum 
is very appealing - very simple - but as far as I can tell, it still 
requires a running installation of SMW+ and I am not ready to make the 
switch yet for several reasons.

So I took another look at my failed attempt at using RAP.

The good news is that I was able to set up RAP and populate it with triples 
without errors (using a full refresh). I checked with MySQL query browser 
and the triples are there. So far so good,

I even figured out what values to give RAP's netapi module as far as 
'model' and 'URI' go (the documentation on SMW page is very light on 
details on that point).

The problem is that I am still missing some configuration regarding setting 
up the actual SPARQL endpoint. 

The server keeps giving me 'Not found' error when I try to access resources 
directly. SPARQL queries are not going anywhere. 

Does anybody know someone who got 'PHP netapi' correctly configured to run 
with Apache and SMW ?

I am willing to write a tutorial or a tip on Referata with the results of 
my experience if anyone is interested.

- Laurent