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[httpRange-14] 303 Redirect Chaining

From: Williams, Stuart (HP Labs, Bristol) <skw@hp.com>
Date: Thu, 7 Jun 2007 11:28:21 +0100
Message-ID: <C4B3FB61F7970A4391A5C10BAA1C3F0DA41753@sdcexc04.emea.cpqcorp.net>
To: "Tim Berners-Lee" <timbl@w3.org>
Cc: <www-tag@w3.org>

Hello Tim,

At our F2F last week we discussed the possible significance of a chain
of 30x redirects arising from an intial attempt to access a
non-information resource, Resource(A)

ie.

	get <A> -> 303: Location <r.1>

	get <r.1> -> 303: Location <r.2>
	...
	get <r.n> -> 303: Location <r.n+1>

	...
	get <r.k> -> 200: Rep(r.k)

IIRC this discussion arose while exploring the suggestion that the first
303 response might be used to infer that target of the first
redirection, Resource(r.1) in the case above, is an information
resource. 

I think that your view was that Resource(r.1) should provide information
about Resource(A), 

	Resource(r.2) about Resource(r.1), 
	..., 
	Resource(r.n) about Resource(r.n-1) 

and so on such that the information provided in the representation
Rep(r.k) contains information about (possibly amongst other things)
Resource(r.k-1). 

Can you clarify whether you thing Resource(r.k) should provide
information about Resource(r.k-1) ONLY or about Resource(r.k-1)
AMONGST-OTHER-THINGS (which potentially includes Resource(A))?

FWIW, I agree that for pragmatic reasons it would be good for such
chains to be short, say just one redirection (though of course some
would prefer zero). However, I would prefer a relaxed understanding of
the signficance of the redirection such that it is regarded as no-more
than a suggestion of a place to look for information about a subject
(Resource(A)). Whether such information is actually available at the
redirection target (Resource(r.1)) cannot be determined without looking.
Looking may involve further redirections. 

I'd be interested in your thoughts. I'm trying to give some thoughts as
to how this (short chains) would be expressed as a good practice. 

BTW: I think that there may also be a principle that arises directly
from the httpRange-14 resolution [1] which could be expressed either as:

a) "Non-information resources cannot have webarch:representations."
(factual) or
b) "Do not deploy webarch:representations for non-information
resources." (imperative)

which is consistent with your response to John Cowan [2] 

Thanks

Stuart (expecting flak)
--
[1] http://lists.w3.org/Archives/Public/www-tag/2005Jun/0039.html
[2] http://lists.w3.org/Archives/Public/www-tag/2007Jun/0024.html
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Received on Thursday, 7 June 2007 10:29:34 UTC

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