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Re: resources, stuffs and individuation

From: Graham Klyne <GK@ninebynine.org>
Date: Wed, 23 Apr 2003 11:00:37 +0100
Message-Id: <>
To: "Roy T. Fielding" <fielding@apache.org>, pat hayes <phayes@ai.uwf.edu>
Cc: uri@w3c.org

At 19:33 21/04/2003 -0700, Roy T. Fielding wrote:
>If you have suggested wording to change, then please suggest it.

OK, I'll take a shot, using the words in [1] as a starting point:

[1] http://www.apache.org/~fielding/uri/rev-2002/rfc2396bis.html#rfc.section.1


     A resource is anything that has identity, to which some kind of 
reference can be made.  Anything can be a resource.  Familiar examples 
include an electronic document, an image, a service (e.g., "today's weather 
report for Los Angeles"), and a collection of other resources. Not all 
resources are network "retrievable"; e.g., human beings, corporations, and 
bound books in a library can also be considered resources.

     A resource may be accessed through a conceptual mapping from a URI to 
an entity or set of entities, and is not necessarily any specific entity 
that corresponds to that mapping at any particular instance in time. Thus, 
a resource can remain constant even when its content---the entities to 
which it currently corresponds---changes over time, provided that the 
conceptual mapping is not changed in the process.

I note that Pat was unimpressed by the term "conceptual mapping", though 
this is something I have found helpful in coming to an understanding of 
resources, even if it is an ill-defined idea.  I expect some further 
improvement in this area is possible.

Maybe there's scope to appeal more directly to some ideas of REST?  e.g.
     On the Web, a URI may be used to access a representation or set of 
representations of a resource.   Such representations are not necessarily 
the resource itself, and an unchanging resource may have representations 
that vary.  Thus, a resource can remain constant even when its 
representations---the entities to which it currently corresponds---change 
over time, provided that the conceptual relationship between the resource 
and its representations is not changed in the process.


Graham Klyne
PGP: 0FAA 69FF C083 000B A2E9  A131 01B9 1C7A DBCA CB5E
Received on Wednesday, 23 April 2003 06:07:59 UTC

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