RE: Prelim. DAV spec.

From: Yaron Goland <yarong@microsoft.com>
Date: Thu, 31 Oct 1996 15:02:40 -0800
Message-ID: <c=US%a=_%p=msft%l=RED-44-MSG-961031230240Z-7801@INET-01-IMC.microsoft.com>
To: "'Larry Masinter'" <masinter@parc.xerox.com>, "'connolly@beach.w3.org'" <connolly@beach.w3.org>

I realize that my new ranges retrieval idea isn't very well baked but
let me give my motivation.

I want to retrieve the AttributeDirectory for a resource but the
directory is HUGE. My poor little WebTV box can't handle that much
memory. I need a way to just pull in a part of the document. I can't use
byte-ranges because I might end up retrieving half of an entry. Imagine
an entry in the AttributeDirectory is "sitemap = http:\foo\bar\blah".
However my byte-range request cut the entry so I only received "sitemap
= http:\foo\bar". The only way I can know there is a problem is if I
request another chunk of the file. This problem also applies to using
DAV for newsgroups or e-mail. The truth is that we are running into a
database problem. How do we retrieve specific records?

I have a feeling that this is a matter for another group. I know that
there has been a lot of talk about having standardized database access
over HTTP around here at MS. Has there already been a W3C or IETF
workgroup on the subject?

Yaron

>-----Original Message-----
>From:	Larry Masinter [SMTP:masinter@parc.xerox.com]
>Sent:	Thursday, October 31, 1996 10:53 AM
>To:	connolly@beach.w3.org
>Cc:	Yaron Goland; ejw@rome.ics.uci.edu; w3c-dist-auth@w3.org
>Subject:	Re: Prelim. DAV spec.
>
>> A representation (or entity -- same thing) is immutable, the way
>> integers and URLs are immutable. How many versions of the number
>> 2 or the string "http://www.w3.org/" are there?
>
>Well, a 'representation' isn't exactly the 'same thing' as an entity.
>We're working in an area where there aren't enough precise terms.
>
>It's very risky to try to make a 'plain logic' argument where we're
>primarily having difficulty with definitions of terms.
>
>Let's try this out along a different dimension than content
>negotiation:
>
>
>HTTP supports 'range retrieval' as well as content negotiation.
>Let's suppose that we allow range retrieval for 'pages' out of a
>single multi-page resource:
>
>   request:
>	Range: pages=1,2
>
>without giving separate URLs for each page independently. There's one
>URL:
>    http://my.server.dom/book/chapter1.pdf
>
>but I can either retrieve the whole thing or several pages at a time.
>One might imagine wanting to 'version' the pages independently, e.g.,
>"version 12 of page 7" and "version 9 of page 12" and even have some
>way of saying "version 10 of the chapter consists of version 23 of
>page 1, ... version 12 of page 7 ... version 9 of page 12 ....".
>
>This isn't logically inconsistent, it's just implementationally
>difficult.
>
>At least in the context of versioning, the part/whole relationship
>bears a strong resemblance to the representation/resource
>relationship.
>
>Larry
>
>
>
>
>
>

Received on Thursday, 31 October 1996 18:02:42 UTC

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