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Re: Qualities of URLs and resources

From: Roy T. Fielding <fielding@kiwi.ICS.UCI.EDU>
Date: Thu, 24 Feb 2000 21:17:09 -0800
To: "Clemm, Geoff" <gclemm@rational.com>
cc: "Slein, Judith A" <JSlein@crt.xerox.com>, w3c-dist-auth@w3.org
Message-ID: <200002242117.aa08003@gremlin-relay.ics.uci.edu>
>There are some concepts that explicitly are not resources,
>e.g. the concept of a "URI" or the concept of a "property".

Nope.  If the concept is referenceable, it is a resource.  If you ask
me for the URL that I was using to represent my home page in 1994,
you are referring to a URI as a resource in itself.  All properties
are resources -- DAV just defines a different way of accessing them
than the old HTTP interface.  The only reason it did so is because
some people felt that adding direct access to properties was better
than paying for one round trip.

>Like URI's and properties, a binding is not
>something that is identified by a URI, and is not something
>to which you can apply requests.  Instead, a binding
>is just a term we use to talk about how a collection 
>resource behaves, e.g. if at time T, a collection resource has a
>binding named "foo" to a resource with DAV:resourceid "xxx", then
>this is just a shorthand for saying that a
>depth:1 PROPFIND at time T on any URL that is mapped to that collection
>will return a DAV:response with a DAV:href whose value is 
>"<that URL>/foo" and with a DAV:resourceid whose value is "xxx".
>
>In other words, all URI's that are mapped to that collection at time
>T will have a member named foo, and the DAV:resourceid of that member
>will be "xxx".

For any concept X, it is possible to create an identifier namespace
obeying the requirements of RFC 2396 such that concept X is unambiguously
identified within the scope of the namespace's usage.  It is therefore
possible to identify any concept with a URI, which makes it a resource.

BTW, DAV:resourceid is an abomination.  It breaks the implementation
abstraction that is at the core of the Web interface.  Telling server
implementors to reveal that information is wrong and is completely
unnecessary to define the protocol.

....Roy
Received on Friday, 25 February 2000 00:17:28 GMT

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