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Re: Indicating query type

From: Leigh Dodds <leigh@ldodds.com>
Date: Tue, 30 May 2006 11:45:09 +0100
Message-ID: <447C2235.9010509@ldodds.com>
To: Danny Ayers <danny.ayers@gmail.com>
CC: public-sparql-dev@w3.org

Danny Ayers wrote:

> But a puzzle I've got is how best to indicate up front whether the
> query is a SELECT, CONSTRUCT, ASK or DESCRIBE. At least I'm assuming
> this is the right way to go - the different query types are quite
> different, from the agent viewpoint presumably they'd correspond to
> different performatives, from the HTTP point of view they're only a
> teeny bit below GET, PUT etc. So I reckon it would make sense to lift
> the query type out of the content somehow (and it should be helpful to
> be able to dispatch at HTTPrequest time, prior to parsing).

Mark Baker made some similar comments:

http://lists.w3.org/Archives/Public/public-rdf-dawg-comments/2005Jul/0066
http://lists.w3.org/Archives/Public/public-rdf-dawg-comments/2005Sep/0013

However I don't see any reason why one couldn't implement a specific
endpoint for each query form (e.g. /ask, /construct) and have that
endpoint reject any "inappropriate" queries.

I don't believe there's anything in the protocol spec which stops a
processor rejecting queries based on type.

This would address your requirement without having to use a custom
header.

You could even implement an "ordinary" SPARQL endpoint which simply
sniffs the incoming query and redirects to the more specific endpoint
as appropriate. Again, from my reading, the protocol spec licenses
this kind of usage as the HTTP binding allows for relatively free
use of HTTP response codes.

Cheers,

L.

-- 
Home: http://www.ldodds.com      | "Simplicity is the ultimate
Blog: http://www.ldodds.com/blog | sophistication" -- Leonardo da Vinci
Received on Tuesday, 30 May 2006 10:45:34 GMT

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