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Re: GULP vs RFC251bis, was: [Bug 54] Locks vs multiple bindings

From: Cullen Jennings <fluffy@cisco.com>
Date: Mon, 19 Dec 2005 21:30:12 -0800
To: Julian Reschke <julian.reschke@gmx.de>
CC: Geoffrey M Clemm <geoffrey.clemm@us.ibm.com>, Lisa Dusseault <lisa@osafoundation.org>, WebDav <w3c-dist-auth@w3.org>
Message-ID: <BFCCD6E4.661D5%fluffy@cisco.com>

On 12/15/05 1:04 AM, "Julian Reschke" <julian.reschke@gmx.de> wrote:

> Cullen Jennings wrote:
>> Perhaps you could explain how one gets multiple bindings when not using
>> an XML database?
> As Geoff, I really don't see what this would have to do with an XML
> database.
> You can get multiple bindings if
> - you support BIND and/or
> - if your underlying store supports something similar, such as a
> filesystem supporting hard links
> Best regards, Julian

Right, no big deal but it seems like a XML database that say had a regular
expression for mapping one URI to another could easily get multiple bindings
to one resource. 

The questions was could you use the DB lock mechanism (or for that matter a
files system lock) to implement DAV locks. Julian said this would not be
compliant with 2516 which I believe but I don't yet understand why it would
not be. 

Now Lisa proposed a model for locking slightly different than GULP which
would, by my understanding, would allow an implementation like GULP but
would also allow implementation like the one I just described to also be
compliant. For a server that supported BIND, it would probably have to be a
GULP like implementation.

Now I have no idea what is best, but I am poking at the form of the
argument. You are arguing the 4 servers tested are compliant with GULP
therefore do GULP. However the 4 servers, by my understanding (happy to be
corrected if I am wrong here), also are compliant with what Lisa proposed
given GULP is a subset of it.

I strongly suspect that there are some DAV like servers out there that try
to use file and data base locking mechanism to do locks - I don't know if
they are 2516 compliant or not. I also suspect there are some servers that
do run regular expression on URL to create multiple bindings to files on a
file system and DELETE will remove both all at the same time. Again, don't
know if this should be legal for a server or not but practically it does not
make much difference for the client so servers will continue to do it.

I like the idea of looking at what is running code today to determine how to
move forward. (I won't ask about if those 4 servers you tested can store gif
files or not :-) 

I'd like to see this discussion have more on what the model should and and
why. So far I can summarize it as:
1) gulp would probably work
2) an alternative model might work
3) some people prefer 1 some 2
4) I've learned a bunch about weak and strong tags and PUT in HTTP - this is
5) I'm not seeing the insights that help people understand why one model or
another would be better or worse.

I really like the posts Dan and Jim where having on the meaning and
implications of etags on PUT. I could read it and understand why one might
want or not want various options.
Received on Tuesday, 20 December 2005 05:30:22 UTC

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