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Re: Is "GET" or "query" the operation?

From: Dan Connolly <connolly@w3.org>
Date: Fri, 24 Jun 2005 14:18:40 -0500
To: Mark Baker <distobj@acm.org>
Cc: public-rdf-dawg-comments@w3.org
Message-Id: <1119640720.5150.25.camel@localhost>

> >Can you sketch a test case
> > that
> > we could use to tell the difference?
> Actually, after much deliberation, no, because "query" doesn't have any
> defined operational semantics in the specification, so I can't test for
> them.

Oh? We have...

"1. query operation
SparqlQuery is the only interface of SPARQL Protocol. It contains one
operation, query, which is used to convey a SPARQL query -- including a
SPARQL query string and an RDF dataset -- and a query result between
clients (requesters) and services (responders)."
 -- http://www.w3.org/TR/rdf-sparql-protocol/

but I don't see anything that says that the results should match
what the SPARQL query language space says they should be.
I guess we should add that.

>  Besides, I fully expect that any test I devise will tell us that
> GET is the operation being used because it comes along for the ride
> whenever you turn URIs into data.  That's my point, really.

If the difference isn't observable on the wire, then this is
a matter of specification style. I leave that for you to discuss
with the editor (though he's bound to meet our requirement
to have a WSDL description of the protocol
http://www.w3.org/TR/rdf-dawg-uc/#r3.14 ).

> > > FWIW, my preference would be that the answer be "GET" and that "query"
> > > be described as purely informative, i.e. not part of any contract.
> > 
> > What would that look like in the spec?
> It would mean a pretty significant rewrite of section 2, since the
> current assumption made there seems to be that the SPARQL spec defines
> the operations (rather than any underlying application protocols), and
> those operations have to be somehow bound to the protocol.  I believe
> that the SPARQL spec should avoid defining operations, or at least avoid
> using them when binding to application protocols.
> Also, it would mean rewriting the WSDL to use http:GET as the operation
> rather than "query".  Here's some WSDL 2.0 written by Dave Orchard to
> describe the Yahoo News services, as an example of this kind of WSDL;
> http://www.pacificspirit.com/Authoring/wsdl/YahooV1Search.wsdl

When I look there, I find, among other things:

 <wsdl:operation ref="yahoowns:Search"

so I don't see what you mean by 'use http:GET as the operation'.

> Note though, that I'm not endorsing the use of WSDL at all - I
> personally think it's underspecified and ambiguous, and only introduces
> confusion, especially in the context of Web based services (i.e. not
> "Web services").  I also don't think it helps describe even SOAP/HTTP
> based services, which you mentioned you were planning to incorporate
> into the spec at a later date.

I think the WG considered concerns like that, though they didn't
carry the day when we decided to adopt the WDSL requirement.

Dan Connolly, W3C http://www.w3.org/People/Connolly/
D3C2 887B 0F92 6005 C541  0875 0F91 96DE 6E52 C29E
Received on Friday, 24 June 2005 19:18:47 UTC

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