Re: [Tracker] tracker RDF data

[Jamie McCracken <jamiemcc blueyonder co uk>]

Eyal Oren wrote:
> Hi,
>
> I'm very interested in tracker. I saw it some months ago, and decided to 
> check back now since it seems more mature and I really like it! 
>
> I'm the developer of ActiveRDF [1], a Ruby library for easy access to 
> various RDF datasources (somewhat similar to ActiveRecord or LINQ for SQL).  
> I'm also working on a big European semantic desktop project called Nepomuk 
> [2].  Nepomuk uses its own crawler and data extractor [4], but I would be 
> very interested in using tracker instead.
>
> It would be great if I could support tracker as an ActiveRDF datasource.  
> Seeing that you use the W3C RDF query language [3], that could be quite 
> easy. What would be best way to programmatically query the tracker 
> database, I guess dbus? What do you return then? Is it possible for you to 
> return RDF (in some serialisation such as ntriples [5])?
>
> It would be great if we could use tracker as the crawled metadata in our 
> semantic desktop.

tracker is not designed for use as a web service but as a desktop 
service (hence dbus is used).

Its also not an RDF style application it merely uses RDFQ (xml based 
version) as a means to query stuff. We dont implement all of RDFQ but a 
subset with extensions. We also only uses the <rdfq:Condition> parts in 
the query so its not a full blown RDF thingy. (you can see rdf query 
examples in the tarball in the rdf-query-examples folder)

The dbus stuff will need Ruby bindings (if they exist?). Queries are 
returned via dbus as a native dict/Hashtable  with the URI as the key 
and an array/list of values as the contents. I expect if you were going 
to make use of it you could serialise this into ntriples yourself.

Im not sure if the above helps or not but it sounds like it would need 
some mods on your part to make use of it.

If there is anything else you need to know feel free to ask.


--
Mr Jamie McCracken
http://jamiemcc.livejournal.com/