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RE: New AFTF draft.

From: David Orchard <dorchard@bea.com>
Date: Wed, 11 Sep 2002 20:22:14 -0700
To: "'Henrik Frystyk Nielsen'" <henrikn@microsoft.com>, <noah_mendelsohn@us.ibm.com>
Cc: "'Carine Bournez'" <carine@w3.org>, "'Christopher B Ferris'" <chrisfer@us.ibm.com>, "'Jean-Jacques Moreau'" <moreau@crf.canon.fr>, "'Herve Ruellan'" <ruellan@crf.canon.fr>, <xml-dist-app@w3.org>, "'Yves Lafon'" <ylafon@w3.org>
Message-ID: <00f601c25a0d$c1cc6db0$0100007f@beasys.com>
Where do you figure there is no mention of a server?  The REST architecture,
particularly section 5 of Dr. Fielding's thesis, explicitly talks about
connectors and components, including caches/proxies/origin servers.  A cache
is only a cache of something from an origin server in the web architecture.

Another way of expressing this, is that just because there is another URI
(the mid: or somesuch for attachments) for a representation, does not mean
that the bytes in-flight suddenly became resources after being retrieved as
representations.  From my POV, and I guess henrik disagrees, is that
Resources are defined by origin servers and not intermediary
formats/representations.

However we express it, I do think we agree about the use of representation
for attachments, which is the real point of this.  

Cheers,
dave

> -----Original Message-----
> From: Henrik Frystyk Nielsen [mailto:henrikn@microsoft.com]
> Sent: Wednesday, September 11, 2002 8:20 AM
> To: noah_mendelsohn@us.ibm.com; David Orchard
> Cc: Carine Bournez; Christopher B Ferris; Jean-Jacques Moreau; Herve
> Ruellan; xml-dist-app@w3.org; Yves Lafon
> Subject: RE: New AFTF draft.
> 
> 
> 
> I would be happy to use the term "representation" but I think 
> it takes a
> bit more to explain than what Dave proposes.
> 
> The traditional Web model is that resolving a URI results in a
> representation of the resource identified by that URI. The "resolver"
> function is of course late bound and can depend on any number 
> of things.
> A "resolution" may involve going to DNS, contacting an HTTP 
> server, etc.
> but the only URI involved is that of the resource. The 
> interesting thing
> is that there really is no fixed, or even named, concept of a 
> "server". 
> 
> When resolution involves an HTTP server, an FTP server, or 
> even a local
> file system, we seem to have no problem mapping this model. 
> In the case
> of a local file system, the resource is the abstract concept 
> of a named
> entity identified by the URI, the actual file is the representation
> resulting from the default resolution process.
> 
> The reason for picking the local file system example is that it is in
> fact very close to what we see in attachments, rather than 
> being a file
> system, it is just some other container. However, applying 
> the same Web
> model, one has a set of URIs identifying resources for which 
> the actual
> bytes included as attachments constitute the representations of these
> resources.
> 
> That is, we never get in the situation where we have to 
> discuss whether
> bags of bytes are resources or representations, they are always
> representations.
> 
> Henrik 
> 
> >I do see both sides to this, but I also think there are some 
> >subtleties (I 
> >must say, I still think the web architecture is broken in 
> the area of 
> >representations.  As I've said before Web arch says:  "everything 
> >important is a resource identified by a URI, representations are 
> >important, representations are not in all cases resources, 
> >representations 
> >are not in all cases identified by and distinguished from other 
> >representations by distinct URIs."  QED.  Feels wrong.  I 
> >think we keep 
> >tripping over it, but I probably don't know what I'm talking about. 
> >Anyway, I'm not sure the answer on what to call the SOAP 
> attachment is 
> >quite so simple thank you!
> 


Received on Wednesday, 11 September 2002 23:41:01 GMT

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