[redland-dev] HTTP interfaces to RDF models

[Frank Smith]

Danny Ayers wrote:
> On 7/7/05, netmeld at netmeld.com <netmeld at netmeld.com> wrote:
> 
>>It's not clear to me if there is anything that's evolving
>>into a 'standard' protocol.
> 
> For read-only querying at least, the SPARQL protocol [1] (scroll past
> the XML Schema bits!) seems to be the point of convergence, for
> instance see comments re. Joseki [2].

That's good to hear.

> For updates/deletes etc...Dave..?

Yes, that's where I'm not seeing anything that looks like an
evolving standard.

> For what its worth, I've been using a simple bit of bridge code [3,4]
> on top of mod_python/Apache2/Debian to access a Redland store over

It sounds like we're working on something quite similar.

I have to say I really like the combination of mod_python/Apache2/Debian.

> HTTP. The querying side has been fairly straightforward using SPARQL.
> I've only been using SELECT but with XML results passed through XSLT
> it's very versatile.
> 
> I'm only now getting to the point where I need to be able to
> systematically modify the store over HTTP (I've got lots of grubby
> little one-off scripts...). I'm hoping a kind of two-phase approach
> will work, first do a SPARQL CONSTRUCT to build a graph, then remove
> all the statements in the generated graph from the main triplestore
> (bnodes may cause problems). Anything that needs to be added can be
> passed as RDF/XML in the body of a HTTP post, or by reference to its
> URI.
> (If anyone's tried this sort of thing already I'd love to hear about
> what works and what doesn't ;-)

I'm going to start implementing something for updating models
over HTTP in the next little while.  

My current work is to develop a good general-purpose HTTP-based 
interface to RDF models (using Redland under the hood).  I'll 
continue to do research for any evolving standards on the model
update/delete front.  

My more long-term goal is to develop a web-based RDF store/model 
provisioning system, with features such as
   * user, storage and model management
   * authentication and access control
   * Not too difficult to set up in a typical web hosting environment

Once I have something working reasonably well, I'll post the code on my
web server, and set up a running system in case anyone wants to
experiment with it.  

-Frank.

> Cheers,
> Danny.
> 
> [1] http://www.w3.org/TR/rdf-sparql-protocol/
> [2] http://groups.yahoo.com/group/jena-dev/message/16827
> [3] http://pragmatron.org/docs/pymplex.html
> [4] http://pragmatron.org/docs/sparqlsphere.html
>