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RE: Why DASL need not be DAV-specific

From: Jim Davis <jdavis@parc.xerox.com>
Date: Mon, 2 Mar 1998 15:03:43 PST
Message-Id: <3.0.3.32.19980302150343.009463e0@mailback.parc.xerox.com>
To: www-webdav-dasl@w3.org
At 01:56 PM 3/2/98 PST, Yaron Goland wrote:

> The reason why this working group was formed was to solve search for DAV.
> ... to provide search facilities which make optimal use of the DAV object
> model, repository model, variant model, access control model, and versioning
> model...Universal Search is a laudable goal but one that will require 
> compromises we are not willing to make.

Perhaps we could all agree as follows:

1) DASL MUST fully support WebDAV repositories efficiently.
2) DASL MAY also support other HTTP applications, if such support imposes
only minor costs (e.g. in added complexity.)

To elaborate on the second point, at present, it seems to me the only DAV
feature that DASL requires is a property store.  Given that we're using XML
to express queries, it would be very easy to generalize the notion of
'property' to support  property stores other than that of DAV.  Surely this
is not objectionable?

We're talking about the difference between (to use an utterly fabricated
query syntax)

<D:contains>
 <D:prop> <X:author/></D:prop>
 <D:value>Knuth</D:value>

and

<D:contains>
 <D:prop><d:dma-guid>123762-72738</d:dma-guid></D:prop>
 <D:value>Knuth</D:value>

Something like that.

As I noted in earlier email, it will also require means to specify query
scope, which may be a bit trickier to generalize, but not too hard.

It may well turn out that when we get into details, there will be something
about DAV that will be too hard to generalize, or something about e.g. LDAP
or Z39.50 that would impose a great penalty on DAV.  If either of these
happen, we should discard the attempt to be universal.

Is this an acceptable framing of the charter?

In the meantime, we can scarcely design DASL's interactions with the
variant, access control, or versioning models of DAV, before these are
designed.  I at least haven't seen any sign of progress on any of these
fronts.  Can you provide any guidance?

Jim


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Received on Monday, 2 March 1998 18:21:51 GMT

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