Now that GRDDL‘s a Recommendation, it’s about time we started using it. One particular bit of (potentially) low-hanging fruit is Atom (RFC 4287) – cleanly specified XML, well deployed for bloggish content syndication and increasingly having interesting extensions shoehorned in.

Anyhow, more on that some other time. I finally got around to trying a long-standing item on my to-do list: RDFize the wonderful Planet Venus aggregator. I reckon a persistent, queryable store of interesting subscriptions is a must-have part of any respectable personal knowledgebase. I haven’t time right now to go into detail on how it works (and in it’s current form you probably wouldn’t want to know), but basically these minimal Python scripts transform Venus’s Atom cache into RDF/XML and post the result of to a Talis Platform store (after first checking the entry isn’t already in the store). So far I’ve got it working enough to make some data available for SPARQling.
If you go to this SPARQL Query form, select the “twitcrit reviews” endpoint with the dropdown and enter a query like this:

PREFIX ar: <http://djpowell.net/schemas/atomrdf/0.3/>

SELECT DISTINCT ?entry ?tp ?title ?cp ?content
WHERE {
[
a ar:EntryInstance ;
ar:entry ?entry;
ar:title [ ?tp ?title ] ;
ar:content [ ?cp ?content ]
]
}
LIMIT 10

- you should see some results.


Next steps are to set up some local caching (thinking of just keeping a list of cache filenames) and turning it over to use the Changeset Protocol rather than the basic unversioned model posts it’s doing now. Once those are in place I’ll make a cron job for it.

There are quite a few different atom2rdf XSLT’s in circulation, the current best-bet frontrunner being one atom2rdf-18.xsl from David Powell, so I used that. Here’s the Venus install, I just pulled out a bunch of the semweb related feeds from my Bloglines subscriptions (note that I cleared the cache earlier today, there was way too much stuff in it for testing).