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Re: Office 2000 read-only

From: Greg Stein <gstein@lyra.org>
Date: Tue, 9 Jan 2001 23:39:54 -0800
To: Jeremy Bach <jeremy@io.mds.rmit.edu.au>, w3c-dist-auth@w3.org
Message-ID: <20010109233954.O4640@lyra.org>
On Tue, Jan 09, 2001 at 05:44:38PM -0800, Jim Whitehead wrote:
> Hi Jeremy,
> 
> Well, I took a quick look at your protocol trace, and nothing obvious
> immediately jumps out at me.  Your lock timout value seems a little high,
> but is less than 2^32-1, which is around 4 billion, if memory serves me
> well.  It's possible Office doesn't like the timeout value to be too far off
> the 120 seconds it requests (although I doubt it, since I have heard of
> other people changing this timeout value without any trouble).

mod_dav has a feature to create a minimum value for the timeout. We've
generally recommended about 10 minutes for the value (and it works fine).
That is nowhere near the 2^32-1, though.

BIG NOTE: Office waits until almost exactly the time specified in the
timeout before refreshing the lock. If Office loses the lock due to a
timeout, then it will *completely* break. The next PUT will pass an If:
header asserting the lock (which is gone), and the PUT will fail with a 412.
Office doesn't know how to recover (e.g. take out a lock again, verify the
etag, etc). The only solution is to have the server say "you time out in N
minutes" but give the app N+M minutes before the real timeout occurs.
mod_dav gives a two minute "fudge factor" for the client to refresh within
the timeout period.

> You're also
> not using a status phrase (the "OK" in "HTTP/1.1 200 OK") in the lock
> response, but this also shouldn't make any difference. One grasping straw
> idea is perhaps Office defaults to read-only if the <isreadonly/> property
> isn't set (you're returning 404 for them).  But then why would Office try to
> lock the document in the first place?

Office locks the document when you open it, then unlocks when you close it.
In between, each "save" does a PUT.

It wouldn't be related to the 404 for isreadonly, cuz mod_dav also 404's
that property.

> Anyone have any ideas on Jeremy's problem?

Nope. I know that mod_dav works, but I've never done a trace. So... I don't
know what the difference would be.

Cheers,
-g

-- 
Greg Stein, http://www.lyra.org/
Received on Wednesday, 10 January 2001 02:39:44 GMT

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