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Re: Proposed AWWW erratum on "information resources" [was Re: Fwd: Splitting vs. Interpreting]

From: David Booth <david@dbooth.org>
Date: Mon, 13 Jul 2009 10:48:04 -0400
To: "Sean B. Palmer" <sean@miscoranda.com>
Cc: www-tag@w3.org
Message-Id: <1247496484.8210.971.camel@dbooth-laptop>
Hi Sean,

On Mon, 2009-07-13 at 10:55 +0100, Sean B. Palmer wrote:
> On Mon, Jul 13, 2009 at 3:24 AM, David Booth<david@dbooth.org> wrote:
> 
> > By design a URI identifies one resource.  The term "resource" is
> > used in a general sense for whatever might be identified by a URI.
> 
> What would these sentences look like if they were written with
> something more like the HTML 5 philosophy?

I don't think I know well enough what the HTML 5 philosophy is to
comment.

> 
> When you look at deployed usage, obviously you find that the http
> scheme is used far more widely than any other scheme. What's the
> second most commonly used scheme? mailto? file?
> 
> I'm sure TimBL now rues using mailto instead of mailbox or mbox or
> some such. If you were to ask someone how many things a file URI
> identifies, what would they say?
> 
> file:///tmp/example.txt
> 
> How many /tmp/example.txt files in the world? Okay, but it only refers
> to the file on the current system. So in that case, is that a product
> of behaviour or is it a reference system?

Yes, that's a good corner case, as that's one that is specifically
designed to be context dependent. So in theory it identifies a single
abstract resource -- the idea of *some* file with that name -- but in
practice context is used to map it to a more concrete, specific file.
In other words, in theory it can still be viewed as identifying a single
thing, but in practice the thing it identifies depends on context.  

> 
> When browser manufacturers come up with new schemes, what kind of
> things are they commonly making and why?
> 
> Safari redirects any http URI that returns application/atom+xml to the
> same URI string only with feed in place of the http scheme. What the
> heck is that all about? What is AWWW teaching us about this, or is
> this not within AWWW's remit?

Do you mean Safari makes up a new URI for it?  Something like
  feed://example/my-feed
instead of
  http://example/my-feed 
?  
That seems a little odd, since it already knows that it has an atom
feed.  Do you know what is the rationale for doing this?

> 
> The most common use of a URI is clicking a link in HTML or pasting it
> in your browser's address bar. And we're not talking most common by a
> slight majority, of course.
> 
> So if we add up all the other uses of URIs, your mailboxes and your
> file URIs and your XML namespaces and your URNs and tags and all kinds
> of things, do they amount to the same body of usage as HTTP URIs used
> in the browser?
> 
> And if we look at the commonalities amongst how these things are used
> and implemented, what do we want to derive from that? What can we
> learn, and what can we teach?

Not sure what you're getting at.  Are you suggesting a completely
different approach to the AWWW's treatment of URIs identifying
resources?

> 
> > An "information resource" is any resource that plays a role
> > in the hypertext Web by producing "representations"
> 
> What server actually works on a model of resources producing
> representations? What web framework works in this way? I've just been
> through the Django tutorial, and I don't see resource being used in
> there.

They all work in this way, though not necessarily using that
terminology.  That's just the terminology chosen by AWWW to describe, at
an abstract level, what happens.  I've simply tried to be as consistent
as possible with existing AWWW terminology while suggesting changes that
would correct the current, flawed definition of "information resource".
Trying to change the terminology beyond that might be useful, but it
would be a much bigger undertaking and is outside the scope of my
suggestion.

> 
> The simple use of current common servers is that files in directories
> are exposed on the web, and maybe you can leave the file extensions
> off. More complex use involves scripting. To someone coding the
> backend to the latest Web 2.0 startup, does "information resources
> produce representations" mean anything?
> 
> If not, where are the extents of the remit again?
> 
> If servers were commonly implemented in Analytica, Lusture, or Prolog,
> that might be one thing. Heck, when I wrote an HTTP client
> implementation in Python I tried to use all the right words from RFC
> 2616. What does your sentence tell me that RFC 2616 doesn't?

Not very much.  :)   It just states it in AWWW terms.

> 
> > Depending on one's perspective (or application) this may be
> > viewed as a case in which the URI unambiguously identifies
> > a resource that has multiple aspects or as a case of ambiguity,
> > in which the artistic work and the web page are each deserving
> > of their own distinct URIs.
> 
> Okay this, to me, is a very admirable attempt to resolve the current
> peculiarities of the situation that we're working on here.
> 
> But why are you saying this? You're only saying this because of RDF,
> not because of some common model of the web. And yet this is
> Architecture of the World Wide Web.
> 
> So don't say that here. It's the wrong place!

In some ways I agree, that it would be more appropriate to put the
material on ambiguity in a separate document on semantic web
architecture (which builds on web architecture, of course).  The reason
I included it here is that that is the only way I can see to explain
what's going on when someone uses the same URI for both a person and a
web page, and someone else complains that that creates an ambiguity.
IMO a critical flaw in the current definition of "information resource"
is the suggestion that it is a class of things that is disjoint from the
class of people or cars or dogs.  I guess the erratum could just remove
the disjointness constraint without further explaining it, but it seemed
to me that people would likely want more of an explanation.

On the other hand, the AWWW *is* already laying the groundwork for RDF
and the semantic web, by talking about URIs identifying things other
than web pages.  And as soon as you talk about a URI identifying one
resource, the issue of ambiguity starts to appear, so it seems difficult
to know how to separate it.


-- 
David Booth, Ph.D.
Cleveland Clinic (contractor)

Opinions expressed herein are those of the author and do not necessarily
reflect those of Cleveland Clinic.
Received on Monday, 13 July 2009 14:48:42 GMT

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