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Re: Bindings, Locks, and MOVE

From: Geoffrey M. Clemm <gclemm@tantalum.atria.com>
Date: Fri, 10 Sep 1999 00:42:47 -0400
Message-Id: <9909100442.AA01057@tantalum>
To: yarong@Exchange.Microsoft.com
Cc: w3c-dist-auth@w3.org
   From: "Yaron Goland (Exchange)" <yarong@Exchange.Microsoft.com>

   That the spec needs to address the issue of cross-server anything indicates
   that the specification is fundamentally broken and needs to be re-written.

Or it means that the section that talks about the cross-server as
a special case is irrelevant and should be deleted.

   The spec should not need to address these issues at all. Rather it should
   provide a well defined start and end state. It is up to the server to figure
   out what that means in application.

Yes, I heartily agree!  That reference to cross server moves in the spec
always bothered me, but it took this note from Yaron to clarify why it
was so bothersome.

 I suspect y'all have taken a serious wrong term somewhere.

Actually "a wrong term" in this context is quite a good pun,
albeit somewhat recursive and probably unintentional (;-).

I believe that it is sufficient to just delete the sentence that talks
about cross server moves.  If a server can implement it, then fine.
If it can't, it needs nothing in the protocol to indicate that it can
fail the request -- it simply must do so.

So please ignore all my burbling about SHOULD's and MAY's in this
regard (which I've quoted below as a form of self flagellation).
Also, I fully agree with Yaron's point in a different thread that a
MOVE is not a COPY followed by a DELETE (and yes, Yaron, I admit it, I
was laughing while reading that thread :-).  My point below was
intended to be that a COPY followed by a DELETE is *not* a MOVE, it is
a COPY followed by a DELETE.


   > From: Geoffrey M. Clemm [mailto:gclemm@tantalum.atria.com]
   >    From: jamsden@us.ibm.com
   >    DAV4J does do cross server COPY and MOVE. This is an important
   >    function required to support publishing web applications. 
   > DAV4J does
   >    it by reusing GET/PROPFIND and PUT/PROPPATCH (followed by DELETE if
   >    MOVE).
   > Let me modify Greg's question just a bit:
   > Is anybody going to be implementing cross-server MOVE as anything
   > more than a cross-server COPY followed by a DELETE?  The reason
   > I ask is that it is a MOVE that has all the tricky interactions
   > with multiple bindings and locks, while a COPY is relatively
   > straightforward (new resources are created, so bindings and locks
   > are not affected).
   > In particular, I'd advocate making cross-server COPY's a MUST
   > (or at least a SHOULD), while a cross-server MOVE's a MAY
   > (or at most a SHOULD).  My main argument against MOVE is that
   > unless the "fixup" step that comes between the logical
   > "COPY and the MOVE" is well defined (as it is in the
   > advanced collection spec), the MOVE semantics is so vague
   > as to be useless.
   > Then a client that wants the COPY/DELETE form of "MOVE" can just
   > issue a COPY followed by a DELETE.
   > Cheers,
   > Geoff
Received on Friday, 10 September 1999 00:42:55 UTC

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