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Re: [RFC2518 Issue] PROPFIND 'allprop' usage

From: <Tim_Ellison@uk.ibm.com>
Date: Wed, 22 Nov 2000 20:00:03 +0000
To: w3c-dist-auth@w3.org
Message-ID: <8025699F.006E2C33.00@d06mta07.portsmouth.uk.ibm.com>


I have to agree with Shaun that providing an unbounded implementation of
'PROPFIND allprops depth infinity' would be brain dead.  Similarly, moving
the goal posts to say that allprops no longer returns all the properties
would be 'unfavourable' to existing clients and servers.

The only tenable position is to allow the server to refuse the request,
either in its entirety (no all props and/or no depth infinity) or by
allowing it to report partial results (a response status code that
indicates not all properties were returned, and/or collection members were
not traversed) for a resource.

IMHO, attempting to synchronize thousands of files with a single call to
the server is not a fantastic idea.

Regards,

Tim


Hartmut Warncke <hwarncke@Adobe.COM> on 2000-11-22 04:58:26 PM

Please respond to Hartmut Warncke <hwarncke@Adobe.COM>

To:   "Hall, Shaun" <Shaun.Hall@gbr.xerox.com>, WebDAV WG
      <w3c-dist-auth@w3.org>
cc:
Subject:  Re: [RFC2518 Issue] PROPFIND 'allprop' usage






> The implications of PROPFIND with an infinite depth affect both the
server
> and/or the client. Supposing you have a large WebDAV enabled repository.
The
> PROPFIND request (a few hundred bytes) could potentially mean that (tens
of)
> GBs of data is to be returned. Even if the server could generate such a
> large response (which is a feat in its own right), it will load the
network,
> and what will happen when the client receives it? Pity the poor user
sitting
> there for a long time (hours?), only to be told "timed out" or "out of
> memory" or something similar.

Yes, of course, I completely understand your point of view. But as a matter
of
fact we like this "depth infinity" feature very much because we can use it
in a
very efficient way in some situations and therefore we are struggleing so
hard
for keeping that feature.

> Changing the specification could break existing products, which is a bad
> thing. Backwards compatibilty should be maintained.

Good to hear that. But I am not quite sure how you will do that because if
a
server has the possibility to refuse a depth infinity request GoLive 5 will
not
be able to handle that situation (synchronization of client and server
content
will not work anymore).

> We think the way forward for the WebDAV specification is to allow servers
> the ability to refuse such requests and inform the client. A mechanism
> should be defined for the client to understand this. If the client
received
> a response which basically stated that the server was refusing to service
an
> infinite depth request, it could issue multiple requests with a Depth:1.

If you have to synchronize a very large site with thousands of files,
replacing
depth infinity requests by depth 1 requests would be a huge performance
disaster
for us.

Best, Hartmut
Received on Wednesday, 22 November 2000 15:04:11 GMT

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