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RE: caching HTTP 303 responses

From: Jacek Kopecky <jacek.kopecky@deri.org>
Date: Thu, 12 Jul 2007 13:40:03 +0200
To: "Williams, Stuart (HP Labs, Bristol)" <skw@hp.com>
Cc: Jeremy Carroll <jjc@hpl.hp.com>, Giovanni Tummarello <g.tummarello@gmail.com>, semantic-web@w3.org
Message-Id: <1184240404.4254.134.camel@localhost>

Hi Stuart, I'm afraid there might be some misunderstanding between us,

On Thu, 2007-07-12 at 12:24 +0100, Williams, Stuart (HP Labs, Bristol)
wrote:
> > For instance the DC case - they have different URIs, and 
> > initially the agent doesn't know anything about them. It 
> > dereferences dc:description, let's say, and finds some 
> > information about that and other DC properties. It can 
> > probably assume now that it need never again (for small 
> > values of never) dereference that. But when it encounters 
> > dc:title, how can the client know that the stuff it got from 
> > the dc:description redirect is all the pertinent information 
> > that it can get from dc:title, which it doesn't yet know to 
> > redirect anywhere?
> 
> Well... does it know *enough* about dc:title not to have to ask the
> question? In an open-world semantic web, finding *all* of anything is
> presumably hard - and determining pertainancy. Maybe, one should take
> the view that if your going to say something about something you should
> say all that you consider pertainent about that thing in the one breath.

The client has never dereferenced dc:title, and that's its primary way
of getting to know about it unless it has some kind of "authoritative
ontology for the DC namespace". It has dereferenced dc:description and
learned something about dc:title, but it has not learned that it has
learned enough.

Perhaps an assertion like this:

<owl:Ontology about="">
  <ex:authoritativeForNamespace rdf:resource="&dc;"/>
</owl:Ontology>

The meaning of namespace here is "all URIs that begin with the given
URI", I guess, or something similar, based on the syntax of the URIs.
It feels a bit dirty to dig into the URIs, but we should take advantage
of the common case that URI hierarchy actually makes sense. 8-)

> FWIW, I sympathise and not being able to use a local cache to avoid the
> round trip it's hard. I think that you can certainly avoid the round
> trip wrt to repeated reference to the *same* thing.

Certainly, I wasn't even considering trying to dereference
dc:description twice here.

Jacek
Received on Thursday, 12 July 2007 11:40:16 GMT

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