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RE: Bindings and Redirect Ref. teleconf. Mar. 1, 2000

From: Greg Stein <gstein@lyra.org>
Date: Mon, 6 Mar 2000 13:32:37 -0800 (PST)
To: WebDAV WG <w3c-dist-auth@w3.org>
Message-ID: <Pine.LNX.4.10.10003061327390.17063-100000@nebula.lyra.org>
I read the section 9.6 in the spec about the Overwrite header itself. It
doesn't mention anything about DELETE. You guys are (IMO, incorrectly)
associating Overwrite with MOVE/COPY. I feel that the right way to look at
it is "what does MOVE/COPY do when Overwrite is present?" Another way to
say it is that you're creating too strong of a binding between the
semantics of the COPY/MOVE methods and the presence of that header.

By your logic, every method should have its own set of associated headers.
We should never share headers. We'll have Overwrite, MKREF-Overwrite, etc.

I wouldn't be upset with a "merge" definition, but I did have to respond
to the way you guys are approaching the problem :-)

Cheers,
-g

On Mon, 6 Mar 2000, Jim Whitehead wrote:
> I agree with Geoff -- the Overwrite header isn't ideal for this case, since
> it has "delete first" semantics, and is always associated with the
> Destination of a COPY/MOVE, not the Request-URI.
> 
> - Jim
> 
> > For both current uses of the Overwrite header (COPY and MOVE), the use
> > of Overwrite means to first delete the resource (if any) that exists at
> > that location.  I.e.:
> >
> >    8.9.3 MOVE and the Overwrite Header
> >
> >    If a resource exists at the destination and the Overwrite header is
> >    "T" then prior to performing the move the server MUST perform a
> >    DELETE with "Depth: infinity" on the destination resource.
> >
> >    8.8.4 COPY and the Overwrite Header
> >
> >    If a resource exists at the destination and the Overwrite header is
> >    "T" then prior to performing the copy the server MUST perform a
> >    DELETE with "Depth: infinity" on the destination resource.
> >
> > To define its semantics for MKREF to differ in this regard
> > seems likely to result in confusion and errors on the part of
> > implementors.
> >
> > In the past, I've proposed that we extend the Overwrite header to allow
> > a "Merge" value (i.e. Overwrite:Merge).  If we did so, then the use of
> > of "Overwrite:Merge" would allow us to consistently use MKREF and an
> > Overwrite header to update the value of the redirect reference.
> >
> > Cheers,
> > Geoff
> >
> >
> > -----Original Message-----
> > From: Greg Stein [mailto:gstein@lyra.org]
> > Sent: Friday, March 03, 2000 5:30 PM
> > To: Slein, Judith A
> > Cc: 'Joe Orton'; WebDAV WG
> > Subject: RE: Bindings and Redirect Ref. teleconf. Mar. 1, 2000
> >
> >
> > Why would it have to delete the properties?
> >
> > Overwrite is defined to "... overwrite the state of a non-null destination
> > resource ...". It is specified in terms of a COPY/MOVE, and we can state
> > that for a MKREF, it *only* overwrites the target.
> >
> > There is no other language that forces us to interpret Overwrite as
> > "DELETE the resource first [implying the props are deleted]".
> >
> > I really like Joe's idea.
> >
> > Cheers,
> > -g
> >
> > On Fri, 3 Mar 2000, Slein, Judith A wrote:
> > > It's certainly a possibility.
> > >
> > > The only problem I can see with relying on MKREF is that it
> > would not just
> > > update the target, but would replace the resource with a new resource.
> > > That's probably harmless if it's an HTTP resource with no
> > properties, but
> > if
> > > it is a WebDAV resource it might have properties that you would like to
> > > preserve while updating its target.
> > >
> > > --Judy
> > >
> > > -----Original Message-----
> > > From: Joe Orton [mailto:joe@orton.demon.co.uk]
> > > Sent: Wednesday, March 01, 2000 7:05 PM
> > > To: WebDAV WG
> > > Subject: Re: Bindings and Redirect Ref. teleconf. Mar. 1, 2000
> > >
> > >
> > > > Issue #6: Need to add rationale for why we use relative URLs.
> > Server is
> > > > required to store it as a relative URL.  Server MUST NOT change the
> > > relative
> > > > URL during a MOVE.
> > > >
> > > > Raises the issue of needing separate methods for getting the
> > value of a
> > > > reference, and modifying the value of a reference.  Tentatively agreed
> > on
> > > > REFGET, REFSET (but noone likes these too much).
> > >
> > > The original -00 spec allowed MKREF with Overwrite, could this be used
> > > instead of REFSET?
> > >
> > > joe
> > >
> >
> > --
> > Greg Stein, http://www.lyra.org/
> >
> 

-- 
Greg Stein, http://www.lyra.org/
Received on Monday, 6 March 2000 16:29:54 GMT

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