W3C home > Mailing lists > Public > w3c-dist-auth@w3.org > January to March 2003

RE: Using If and not failing

From: Lisa Dusseault <lisa@xythos.com>
Date: Sat, 1 Feb 2003 11:27:17 -0800
To: "'Clemm, Geoff'" <gclemm@rational.com>, "'Webdav WG'" <w3c-dist-auth@w3c.org>
Message-ID: <009d01c2ca27$ef254e50$f876fea9@xythoslap>


To be clear, I did not object to the proposal per se.  I've been echoing
the recommendation that it's at least a good interim solution, and I
only tweaked the solution you call the "final form" in my recent emails.

However, I felt the proposal wasn't sufficient to completely solve the
interoperability problems.  I still worry on that point, and I'm *not*
the only one.  

 - Jim W has expressed concern that any proposal that allows the If
header to succeed regardless of server state is weakening the ability of
the If header to correct the client's incorrect state. That objection
applied both to a "here are all my locktokens" approach and to the
proposals showing how to work around the current syntax.

 - Dan Brotsky saw these proposals and still felt strongly that a much
more simple approach was necessary for long-term interoperability.

In other words, we're not done yet.  We are still refining our
understanding of various issues and proposals surrounding the If header.
The If header still has other problems:

 - the "ignored clauses" that the list decided shouldn't be ignored
 - Uncertainty or at least implementation differences in what locks are
required to do various operations
 - Confusion on whether multiple lists are ANDed together (tagged list)
or ORed together (no-tag)
 - You(geoff) suggested dropping the no-tag-list production (Oct 7 2002)
 - Jason suggested that no-tag-list production always apply to
Request-URI only (Oct 12 2002)

We still need more input from more WG members. 

Lisa

> -----Original Message-----
> From: w3c-dist-auth-request@w3.org 
> [mailto:w3c-dist-auth-request@w3.org] On Behalf Of Clemm, Geoff
> Sent: Saturday, February 01, 2003 7:15 AM
> To: 'Webdav WG'
> Subject: RE: Using If and not failing
> 
> 
> 
> Yes, this proposal appears in the thread 
> "Submitting tokens without a validity check"
> http://lists.w3.org/Archives/Public/w3c-dist-auth/2002OctDec/0284.html
> based on a suggestion from Stefan:
> http://lists.w3.org/Archives/Public/w3c-dist-auth/2002JulSep/0
> 390.html 
> The final form of this proposal (with constant
> tokens) appears in a message from Julian:
> http://lists.w3.org/Archives/Public/w3c-dist-auth/2002OctDec/0286.html
> 
> Since at the time, Lisa was the only one who
> objected to this proposal, it sounds like we
> now all agree that this is the right approach?
> 
> Cheers,
> Geoff
> 
> 
> -----Original Message-----
> From: Julian Reschke [mailto:julian.reschke@gmx.de]
> Sent: Saturday, February 01, 2003 4:58 AM
> To: Lisa Dusseault; 'Webdav WG'
> Subject: RE: Using If and not failing
> 
> 
> 
> Lisa,
> 
> you are aware that this exactly the proposal that Geoff and 
> myself have been
> making for some months now?
> 
> Julian
> 
> --
> <green/>bytes GmbH -- http://www.greenbytes.de -- tel:+492512807760
> 
> > -----Original Message-----
> > From: w3c-dist-auth-request@w3.org
> > [mailto:w3c-dist-auth-request@w3.org]On Behalf Of Lisa Dusseault
> > Sent: Saturday, February 01, 2003 7:15 AM
> > To: 'Lisa Dusseault'; 'Webdav WG'
> > Subject: RE: Using If and not failing
> >
> >
> >
> >
> > I've been looking into this some more. This trick should 
> also work with
> > tagged lists.  However, since multiple tagged lists are 
> ANDed together
> > (" If the state of the resource to which the header is 
> applied does not
> > match any of the specified state lists then the request 
> MUST fail") it
> > has to be done a little differently.
> >
> > <no-lock> here represents a lock token that the client made 
> up, which is
> > intended to Fail.
> > If: <href1> (<locktoken1> Not <no-lock>) <href2> (<locktoken2> Not
> > <no-lock>)
> >
> > This evaluates as
> > 	((href1 matches locktoken1) OR NOT (href1 matches no-lock))
> > 	AND  ((href2 matches locktoken2) OR NOT (href2 matches no-lock))
> >
> > I tested this against Xythos WFS, and clients can use this syntax to
> > make sure that the request does not fail even if locktoken1 or
> > locktoken2 are no longer there.  Of course this should 
> always be used
> > with ETag checks.
> >
> > lisa
> >
> >
> > > -----Original Message-----
> > > From: Lisa Dusseault [mailto:lisa@xythos.com]
> > > Sent: Thursday, January 23, 2003 12:20 PM
> > > To: Webdav WG
> > > Subject: Using If and not failing
> > >
> > >
> > >
> > >
> > > Did anybody point out that there's an interesting way for the
> > > client to
> > > ensure that the If header never fails the request, by always
> > > providing a
> > > "true" statement?
> > >
> > > -          One or more tokens can be put in parentheses to
> > > form a group
> > > or list
> > > -          Multiple lists can be included and they are 
> ORed together
> > >
> > > So if the client wants to put a bunch of locktokens in the If
> > > header it
> > > can put any number of them in there, all separated by 
> virtual "OR"s:
> > >
> > > DOSTUFF /resourceurl.html HTTP/1.1
> > > If: (<locktoken1>) (<locktoken2>) (<locktoken3)
> > >
> > > This request will succeed if the any of the clauses match.
> > >
> > >
> > >
> > >
> >
> >
> 
> 
Received on Saturday, 1 February 2003 14:27:20 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Tuesday, 2 June 2009 18:44:02 GMT