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Re: Alternative dereference behavior

From: Martin J. Dürst <duerst@it.aoyama.ac.jp>
Date: Tue, 29 Sep 2009 18:22:14 +0900
Message-ID: <4AC1D1C6.3090500@it.aoyama.ac.jp>
To: Larry Masinter <masinter@adobe.com>
CC: Jonathan Rees <jar@creativecommons.org>, Dan Connolly <connolly@w3.org>, "www-tag@w3.org" <www-tag@w3.org>
Just a very small comment: I think one other kind of "out-of-band" 
information may be the protocol/format context in which the URI is used. 
The example I'm thinking about is that there are different resolution 
(or non-resolution) expectations for an XML namespace URI, an RDF 
namespace URI, an a@href URI, an img@src URI, and so on. (The later two, 
even if identical, might in some (admittedly very rare and special) 
setups lead to different stuff returned based on different Content-Types 
used.)

Regards,    Martin.

On 2009/09/29 7:03, Larry Masinter wrote:
> A URI (or URL or IRI or whatever) is a communication from a
> URI producer to a URI consumer, which identifies a resource
> the URI producer wants the URI consumer to identifier.
>
> If the URI consumer wants to understand the communication,
> the URI consumer needs to understand what the URI producer
> intended.
>
> " does it leave open the possibility of conforming agents
>    using mechanisms that give answers at variance with what
>    the Web would give?"
>
> Consumers of URIs that use mechanisms other than the
> one indicated by the URI itself must somehow be using
> additional information that isn't contained within
> the URI itself.  I don't think it should be part of
> the "Web canon" to forbid the use of additional
> out-of-band information, but certainly such use is
> "non-conforming" within the domain of applicability.
>
> One additional piece of information which is often
> necessary but not part of the URI is the timeframe
> in which access is expected. So 100 years from now,
> if an interpreter of a 100-year-old document comes
> across "http://www.netscape.com", the interpreter
> (a URI consumer) may well use some out of band
> information to understand and interpret what was
> likely meant by the producer of that URI.
>
> Other examples of out-of-band information come from
> local configuration information (intranet users
> allowing WINS resolution of domain names) and
> "transparent proxies", where organizations intercept
> HTTP traffic and try to redirect requests to local
> caches as a way of reducing net bandwidth use
> and improving latency.
>
> There is no simple way to normatively ALLOW or
> DISALLOW a URI consumer from using out-of-band
> information to pick a different resolution method,
> but this doesn't change the fact that the URI
> producer's *meaning* is the one indicated by the
> URI scheme itself, even if the producer is aware
> of and takes into consideration the consumer's
> likely additional behavior.
>
> I think the discussion of "meaning" without
> being clear about "to whom" and "when" is
> very difficult and leads to incorrect
> conclusions and contradictions; be
> careful to use "meaning" as verb (someone
> means something at some point in time)
> rather than an attribute (X has meaning
> Y).
>
> Sometimes within a given document you don't
> need to qualify all those things, if the
> document itself is clear (alas, not the
> case for most of the documents we're discussing.)
>
> Larry
> --
> http://larry.masinter.net
>
>
> -----Original Message-----
> From: www-tag-request@w3.org [mailto:www-tag-request@w3.org] On Behalf Of Jonathan Rees
> Sent: Monday, September 28, 2009 2:29 PM
> To: Dan Connolly
> Cc: www-tag@w3.org
> Subject: Re: Alternative dereference behavior
>
> On Mon, Sep 28, 2009 at 4:04 PM, Dan Connolly<connolly@w3.org>  wrote:
>> On Mon, 2009-09-28 at 13:00 -0400, Jonathan Rees wrote:
>>> This message is pursuant to ACTION-312 which I took on at the F2F.
>>>
>>> Roughly speaking, the question is: Does the canon say that the Web is
>>> the authority for http: URI "dereference" (GET), or does it leave open the
>>> possibility of conforming agents using mechanisms that give answers
>>> at variance with what the Web would give?
>> [...]
>>> Summary:
>> [...]
>>>    . General advice (AWWW, IAB TC) is that if you "split the web" by making URIs
>>>      non-global you are doing something really tragic.  A change
>>>      in the rules for dereference would theoretically be OK, as long as everyone
>>>      made the change in step (ha!).
>> Exactly. That seems like a "yes" answer to the question above,
>> inasmuch as an authority is something that helps you avoid something
>> really tragic.
>>
>> I don't see any contradiction with my reading of webarch;
>> maybe the description of the action should change or something?
>>
>> "Find a path thru the specs that I think contradicts Dan's reading of
>> webarch"
>>   -- http://www.w3.org/2001/tag/group/track/users/38732
>
> I will not be able to complete this action, because you were right and
> I was wrong.
> So I think the action does need to be changed or dismissed.
>
> Jonathan
>

-- 
#-# Martin J. Dürst, Professor, Aoyama Gakuin University
#-# http://www.sw.it.aoyama.ac.jp   mailto:duerst@it.aoyama.ac.jp
Received on Tuesday, 29 September 2009 09:23:24 GMT

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