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RE: DELETE in WebDAV Advanced Collections

From: Slein, Judith A <JSlein@crt.xerox.com>
Date: Fri, 23 Apr 1999 11:32:22 -0400
Message-ID: <201BB34B3A73D1118C1F00805F1582E801BA4DB1@x-wb-0128-nt8.wrc.xerox.com>
To: "'Roy T. Fielding'" <fielding@kiwi.ics.uci.edu>, "Slein, Judith A" <JSlein@crt.xerox.com>
Cc: "'WebDAV'" <w3c-dist-auth@w3.org>
Thanks for the great explanation of what a resource is.  This is certainly
the clearest explanation that I've seen, and the examples are especially
helpful.  It makes me feel much more comfortable about the direction we are
headed.

--Judy

Judith A. Slein
Xerox Corporation
jslein@crt.xerox.com
(716)422-5169
800 Phillips Road 105/50C
Webster, NY 14580


> -----Original Message-----
> From: Roy T. Fielding [mailto:fielding@kiwi.ics.uci.edu]
> Sent: Thursday, April 22, 1999 5:32 PM
> To: Slein, Judith A
> Cc: 'WebDAV'
> Subject: Re: DELETE in WebDAV Advanced Collections 
>  
> Keep in mind that the web's model upon which RFC 2068 was 
> based defines
> a resource as a semantic binding between a URI and a set of 
> representations.
> The server cannot "remove all URIs for the resource" unless it has the
> ability to determine the semantics of those URI.  In fact, 
> the only ones
> it does remove are those that cannot exist without the presence of the
> request-URI.
> 
> For example, in an Apache negotiation-capable directory, the 
> presence of
> 
>     one.txt
>     two.txt
>     two.htm
> 
> also implies the existence of the bindings
> 
>     one
>     two
> 
> If a client were to request a DELETE on "one.txt", then first 
> "one.txt" is
> removed (to obey the client request) and the binding for 
> "one" disappears.
> If a client were to request a DELETE on "two.txt", then only "two.txt"
> is removed.  If a client were to request a DELETE on "one", it should
> get a response saying "this is not the source, see one.txt".  
> Of course,
> this is the simplest case -- Apache knows the semantics of these URI
> because they share a single handler.
> 
> The other thing to keep in mind is that the fact that two URI are
> currently mapped to the same representation (file) on the server does
> not mean that they are necessarily the same resource.  If I have one
> resource for "today's weather in Irvine" and another for 
> "Irvine weather
> report for 22 Apr 1999", they will map to the same 
> representation today
> and different representations tomorrow.  The resource is the 
> concept being
> linked to via hypertext, not the representation of that 
> concept that is
> retrieved on a given request.  That is why, in order to 
> author any resource,
> the author must first find the specific source resource URI 
> (the URI that
> binds to the handler's underlying representation for the 
> target resource).
> 
Received on Friday, 23 April 1999 11:29:27 GMT

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