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RE: Interest in standardizing Batch methods?

From: Stefan Eissing <stefan.eissing@greenbytes.de>
Date: Wed, 9 Jan 2002 16:46:48 +0100
To: "Clemm, Geoff" <gclemm@rational.com>, "WebDAV" <w3c-dist-auth@w3.org>
Message-ID: <NDBBKJABLJNMLJELONBKMENBDCAA.stefan.eissing@greenbytes.de>
> From: w3c-dist-auth-request@w3.org
> [mailto:w3c-dist-auth-request@w3.org]On Behalf Of Clemm, Geoff
> Sent: Wednesday, January 09, 2002 4:17 PM
> To: WebDAV
> Subject: RE: Interest in standardizing Batch methods?
>
>
> A single MOVE, DELETE, or PROPPATCH request is idempotent
> (repeating the same request multiple times produces the
> same result as just doing it once).

Not quite: A second MOVE/DELETE/PROPPATCH will return a
different result to the client. So a second DELETE will
answer 404 instead of 204.

The server "state" will stay the same. I think that's
what you had in mind.

> A sequence of DELETE's is always idempotent.  A sequence of PROPPATCH's
> is always idempotent if the same property isn't updated by different
> PROPPATCH requests in that sequence.  A sequence of MOVE's is always
> idempotent if none of the Destination URLs overlap with any of the
> request URL's.
>
> Cheers,
> Geoff
>
>
> -----Original Message-----
> From: Julian Reschke [mailto:julian.reschke@gmx.de]
> Sent: Wednesday, January 09, 2002 3:34 AM
> To: Lisa Dusseault; Greg Stein; Jim Whitehead
> Cc: WebDAV
> Subject: RE: Interest in standardizing Batch methods?
>
>
> Looking at RFC2616:
>
> "8.1.2.2 Pipelining
> Clients SHOULD NOT pipeline requests using non-idempotent methods or
> non-idempotent sequences of methods
> (see section 9.1.2).
>
> So it seems that pipelining wouldn't be allowed for anything
> except PROPFIND
> (MOVE/DELETE/PROPPATCH aren't idempotent), right?
>
> > -----Original Message-----
> > From: w3c-dist-auth-request@w3.org
> > [mailto:w3c-dist-auth-request@w3.org]On Behalf Of Lisa Dusseault
> > Sent: Wednesday, January 09, 2002 6:30 AM
> > To: Greg Stein; Jim Whitehead
> > Cc: WebDAV
> > Subject: RE: Interest in standardizing Batch methods?
> >
> >
> >
> > > Personally, I'm going to guess they didn't pipeline requests,
> so a batch
> > > mechanism was a must to get around deficiencies in their
> protocol stack.
> >
> > There's potentially a little more to it than that.
> > (1) Imagine a client selects a bunch of resources and drags to
> > move them all
> > to a different folder.  A batch MOVE operation can do those in one
> > transaction, so that the whole request fails if not all can be
> > moved.  This
> > becomes rather more important if the client is actually using an API
> > (MSDAIPP??) that offers large-scope operations, yet how can it guarantee
> > that operation will work or won't work if it can only send it
> piecemeal to
> > the server?
> >
> > (2) See Yaron's email
> > (http://lists.w3.org/Archives/Public/w3c-dist-auth/1998OctDec/0303.html)
> > about why pipelining doesn't always work (can't always be used even when
> > available).  I don't know to what extent pipelining is realistically
> > unavailable/unworkable.
> >
> > That said, it's still not clear batch methods are so necessary they'd
> > preempt other work we've got to do.
> >
> > Lisa
> >
>
>
>
Received on Wednesday, 9 January 2002 10:47:41 GMT

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