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Re: Review of new HTTPbis text for 303 See Other

From: Xiaoshu Wang <xiao@renci.org>
Date: Tue, 14 Jul 2009 11:20:42 -0400
Message-ID: <4A5CA24A.9050604@renci.org>
To: Pat Hayes <phayes@ihmc.us>
CC: Richard Cyganiak <richard@cyganiak.de>, "Roy T. Fielding" <fielding@gbiv.com>, Jonathan Rees <jar@creativecommons.org>, Julian Reschke <julian.reschke@gmx.de>, HTTP Working Group <ietf-http-wg@w3.org>, www-tag@w3.org
Pat Hayes wrote:
>
> On Jul 14, 2009, at 9:01 AM, Xiaoshu Wang wrote:
>
>> Pat Hayes wrote:
>>
>> <snip>
>>>> on these two counts, you end up ranting against a POV that I do not 
>>>> hold.
>>>>
>>>> I especially continue to maintain that any talk about denotation is 
>>>> out of place on the HTTP protocol level. There is no such thing as 
>>>> denotation in the universe of the Hypertext Transfer Protocol. Yes, 
>>>> people obviously use HTTP URIs to denote all sorts of things, and a 
>>>> lot can be said about how one should model resources and 
>>>> representations based on the things one wants to denote, and what 
>>>> one can or cannot infer about the denotation of a URI based on HTTP 
>>>> interactions, but none of this matters one bit for the actual 
>>>> operations of the protocol.
>>>
>>> Seems to me that this may have been true before http-range-14, but 
>>> it is not a stance that can possibly be maintained in the face of 
>>> that decision. And your final sentence above is, surely you can 
>>> yourself see, tendentious. If the HTTP 'layer' really were 
>>> completely unconcerned with denotation, how could one *possibly* 
>>> infer anything about what a URI denotes from *anything* about HTTP 
>>> interactions?
>> The assumption here is that httpRange-14 is the right direction.  But 
>> that is a big *if*. If anything, this debate only shows how *bad* 
>> that this whole idea of httpRange-14 and information resource thing is.
>
> As I said in another post, I think http-range-14 is terrible, but all 
> the alternatives are worse.
Of course there is no better alternative because there is *not* a 
problem at the first place. The problem is created by pushing IR into 
the Web architecture.  But just like the web architecture should not 
deal with hamburgers, it should not deal with IR as well.

>>>> The protocol is just about pushing representations around.
>>>
>>> Well, I would be delighted if this were true. But then the HTTP 
>>> specs should not claim or even hint at the idea that URIs can 
>>> "identify" non-computational things, or that such things can have 
>>> "representations" in its specialized sense. (It would be very good 
>>> manners, in fact, to clarify just what that highly specialized sense 
>>> of "representation" is, and state explicitly that it is not intended 
>>> to cover any wider sense of representation, for example the sense in 
>>> which it it used in such phrases as "knowledge representation".) And 
>>> you should be quite open and clear about the fact that this view of 
>>> HTTP is not compatible with the http-range-14 decision.
>> The HTTP protocol should be about pushing representation around.  And 
>> it shouldn't careless about if its URI denotes or identifies 
>> anything.  The latter is up to the one who implements that particular 
>> URI.   Let's not ignore the existence of such entities because it is 
>> those who expressed their denotation semantics.
>>
>> Also, let's us not play linguistic tricks.  If the owner of 
>> "http://example.com/a.hamburger" makes it to denote a hamburger. Then 
>> HTTP-GET "http://example.com/a.hamburger" means "get me an 
>> awww:representation" of the hamburger. But it does NOT mean the "get" 
>> like in "get me that hamburger" as what we would say in front of a 
>> grill.
>
> Of course not. But it also does not mean, "get me an 
> awww:representation" of the hamburger. Or at least, it had better not 
> mean that, since hamburgers don't have awww:representations. Web pages 
> about hamburgers can represent (not awww:represent) a hamburger, and 
> they of course have awww:representations. But an awww:repreresentation 
> of a representation of X is not an awww:representation of X.
I mentioned that let us not ignore *the existence of an agent* -- the 
one who implements the URI.  I do not know if a hamburger *can or 
cannot* have an awww:representation because I am not a hamburger.  But I 
do know that *I can* give a hamburger an awww:representation.  You don't 
have to believe me, that is none of my business.  But to say that no one 
should believe me, you cross the line for being either ignorant (of 
being me) or arrogant (of being you).
>> To think otherwise is to hallucinate.
>
> Quite.
>
>>
>> httpRange-14 was at first designed to prevent people from episodes of 
>> this kind of hallucination.  But at the end, it ends up with its own 
>> one -- the hallucination of the information resource.
>
> I don't like the terminology (and I don't think we need it, and 
> especially do not need to be debating its exact meaning), but the 
> general idea is clear enough: its the thing that HTTP returns the 
> awww:representation of. That is certainly not a hallucination, because 
> you just made HTTP contact with it.
Then, it is fine with me.  You can call an HTTP server, FTP server, 
Mailto server or any kind of information server -- an "information 
resource".  That is denotation semantics of that word's use.  It is fine 
with me because we might just call it "xyz" -- for the sake of avoiding 
confusion.  But this denotation semantics should not affect how *I* 
implement *my* URI.  Most of all, it should not affect how *I* use the Web.

Xiaoshu
Received on Tuesday, 14 July 2009 15:21:31 GMT

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