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Re: Is 303 really necessary?

From: Pat Hayes <phayes@ihmc.us>
Date: Fri, 5 Nov 2010 12:29:38 -0500
Cc: Dave Reynolds <dave.e.reynolds@gmail.com>, Norman Gray <norman@astro.gla.ac.uk>, Linked Data community <public-lod@w3.org>, Ian Davis <me@iandavis.com>
Message-Id: <1FBA56B1-01BC-47FD-9135-16EB928D66D8@ihmc.us>
To: nathan@webr3.org

On Nov 5, 2010, at 7:52 AM, Nathan wrote:

> Dave Reynolds wrote:
>> On Fri, 2010-11-05 at 12:11 +0000, Norman Gray wrote: 
>>> Greetings,
>>> 
>>> On 2010 Nov 4, at 13:22, Ian Davis wrote:
>>> 
>>>> http://iand.posterous.com/is-303-really-necessary
>>> I haven't been aware of the following formulation of Ian's problem+solution in the thread so far.  Apologies if I've missed it, or if (as I guess) it's deducible from someone's longer post.
>>> 
>>> vvvv
>>> httpRange-14 requires that a URI with a 200 response MUST be an IR; a URI with a 303 MAY be a NIR.
>>> 
>>> Ian is (effectively) suggesting that a URI with a 200 response MAY be an IR, in the sense that it is defeasibly taken to be an IR, unless this is contradicted by a self-referring statement within the RDF obtained from the URI.
>>> ^^^^
>>> 
>>> Is that about right?  That fits in with Harry's remarks about IRW, and the general suspicion of deriving important semantics from the details of the HTTP transaction.  Here, the only semantics derivable from the transaction is defeasible.  In the absence of RDF, this is equivalent to the httpRange-14 finding, so might require only adjustment, rather than replacement, of httpRange-14.
>> Very nice. That seems like an accurate and very helpful way of looking
>> at Ian's proposal.
> 
> The other way of looking at it, is that the once clear message of:
> 
>  Don't use /slash URIs for things, use fragments, and if you flat out
>  refuse to do this then at least use the 303 to keep distinct names
> 
> has been totally lost.
> 
> The advice is not that /slash URIs are okay and use them if you like, it's that they're not ok and you should be using #fragments. Don't dress the TAG finding up in other words to make it seem more favourable than it actually is.

That isnt the way I read the TAG finding. I read it as simply saying that if you use a slash URI and you want it to denote something other than what it http-GETs, then use a 303 redirect. Because a slash URI which returns a 200 code is understood as being a name for the IR that it is connected to with HTTP; the 200 code amounts to a claim that HTTP has over its denotation. And the 303 cancels that claim, leaving it free to denote whatever y'all want it to denote, just like a hash name with a fragment. 

And thats all.

Pat

> 
> I think this needs to be made clear for all those who don't realise.
> 
> Best,
> 
> Nathan
> 
> 
> 
> 
> 
> 

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Received on Friday, 5 November 2010 17:31:21 UTC

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