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Re: Hierarchical URLs and Collections

From: Roy T. Fielding <fielding@kiwi.ics.uci.edu>
Date: Fri, 21 Aug 1998 15:52:48 -0700
To: Larry Masinter <masinter@parc.xerox.com>
cc: WebDAV working group <w3c-dist-auth@w3.org>
Message-ID: <9808211552.aa15450@paris.ics.uci.edu>
>The objection to the current WebDAV spec is that it requires the
>client to parse the URL in ways that are otherwise not required.

Ummm, no, the requirements are on the server.  WebDAV needs to specify
the consequences of an action upon a collection resource.  In order to
do that, it must specify the difference between resources that exist
independently of the collection and not independently of the collection,
meaning that if you move or delete the collection those resources also
get moved or deleted.  It does so by declaring the latter things to be
'internal members' and distinguising them as such by requiring their
reference to be relative within the collection namespace.

>For example, if put up a DAV server as
>
>     http://myserver.com/people/masinter/cgi-bin/DAVSERVER/root
>
>I might want to treat 'root' as a container, but not have the client
>assume that the parent of 'root' is
>    http://myserver.com/people/masinter/cgi-bin/DAVSERVER
>and that the parent of that resource is
>    http://myserver.com/people/masinter/cgi-bin/

The client is not given the right to assume anything about the namespace
above a collection.  If root is not contained within DAVSERVER, then
it must be an external member or alias of DAVSERVER, but that is controlled
by the server and not the client.  AFAIK, WebDAV just requires special
things to happen if it is an internal member -- this does not imply that
everything within a namespace is an internal member.

I agree that the WebDAV spec is incomplete in that it doesn't deal with
the very real issues of external members and aliases, but that is precisely
what the advanced collections spec is about.  I wouldn't be at all
surprised that a DMS can't take full advantage of its namespace abilities
without the advanced collections.  But that does not mean a DMS can't
implement WebDAV.

....Roy
Received on Friday, 21 August 1998 18:55:08 GMT

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