Subject: RE: etags in If: headers (was: 54th IETF Meeting Information, and RFC2518 open issues)

From: "Jason Crawford" <[email-masked]>
Date: Thu, 25 Apr 2002 15:46:12 -0400

<<
I think a key point is the one Greg made at the end of this message,
namely that this use case can be achieved without allowing etags in
the If header.  In particular, you just try the PUT with the LOCK
request, and if that fails because you no longer have the lock, you
retry the PUT with the appropriate etag in an If-Match header.  I
think it is very reasonable to require an extra round trip in an
exceptional case like this (i.e. losing your lock).
Or depending on your purpose, just skip directly to the second step
of using the If-Match header.  It depends on what you're trying to
achieve.

------------------------------------------
Phone: 914-784-7569,   [email-masked]

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From: "Jason Crawford" <[email-masked]>
Date: Fri, 26 Apr 2002 01:06:02 -0400

<<
Well, using also ETag verification allows consistency check. If you still
have your lock and the ETag has changed, then it's because something nasty
happened on the server side (as the ETag represents more or less a version
tag of the resource).
As it won't cost anything, I don't understand why you want to remove a
consistency check.
He wasn't suggesting giving up the consistancy check.  He was suggesting
you
can already do that consistancy check without IF:/etag.  You can use
HTTP's IF-MATCH:/etag instead in most cases.

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From: "Clemm, Geoff" <[email-masked]>
Date: Fri, 26 Apr 2002 07:33:46 -0400

You don't need to put the Etag in the If header to get the consistency
check;
you can just use both the If header with the lock token and an If-Match
header with the Etag.

I really don't care whether or not we keep the Etag semantics in
the If header.  The issue was that if it is not being used in practice by
clients, then it needs to be deleted when we go to proposed standard,
unless there were good arguments for keeping it in (and no such good
argument seems to have yet been fielded).

Cheers,
Geoff

-----Original Message-----
From: Yves Lafon [mailto:[email-masked]]
Sent: Thursday, April 25, 2002 10:23 PM
To: Clemm, Geoff
Cc: Webdav WG (E-mail)
Subject: RE: etags in If: headers (was: 54th IETF Meeting Information,
and RFC2518 open issues)

On Thu, 25 Apr 2002, Clemm, Geoff wrote:

> So until a use case is identified that cannot be easily handled by
> other machinery, I suggest we limit the If header to just lock tokens.

-- 
Yves Lafon - W3C