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Re: fetching from a baseline on a readonly server

From: Geoffrey M. Clemm <geoffrey.clemm@rational.com>
Date: Tue, 16 Jan 2001 22:09:41 -0500 (EST)
Message-Id: <200101170309.WAA18066@tantalum.atria.com>
To: ietf-dav-versioning@w3.org

   From: Greg Stein <gstein@lyra.org>

   As a variant of my previous question, how would I fetch a particular file
   from a particular baseline on a readonly server? Specifically, if I'm not
   allowed to do a MKCOL, a BASELINE-CONTROL, or an UPDATE (on an existing
   baseline selector), then how can I use a baseline?

OK, I was wavering before, but now you've pushed me over the edge.  I
believe it is reasonable to do what you want, and you shouldn't have
to do a "write" operation to get it.  So I propose the following:

Add a DAV:baseline-collection property on a baseline, which holds
a DAV:href containing a server-defined URL.  This URL identifies
a read-only collection that exposes that baseline as a collection.
Access to that read-only collection would be the message to the
server to "cache" that baseline as a collection.  The server
would then just have to automatically clean up that cache when it
needs the space, rather than counting on a DELETE from the client
to tell it when to do so.

This is a burden on the server, but probably not an unreasonable one.
In particular, I don't think that Greg's will be the only server that
will have very different performance/implementation tradeoffs for a
read-only view of a baseline (what Greg wants) and a writeable view of
a baseline (aka a workspace).

   Conceivably, I could get the version-history for a given VCR, use a
   DAV:baseline-version report to find the specific version of that collection,
   get the collection version's members and execute DAV:baseline-version on
   those, etc. But this is a far cry from random-access to a specific path
   within a baseline.

Yes, that would be really gross.

   Note that I can't simply use the Depth: header, as that would apply "once"
   to the collection version history (which has no children); the Depth header
   would not apply to the collection versions.

Yes, that wouldn't work.



So, Greg: Does the DAV:baseline-collection property on a baseline
give you what you want (I presume, yes).

So, everyone else: any objections?  (For Greg at least, I presume, no :-).

Cheers,
Geoff
Received on Tuesday, 16 January 2001 22:10:36 GMT

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