Next message: Tim Ellison/OTT/OTI: "Re: workspaces as collections"
Date: Wed, 31 May 2000 07:55:28 -0400 (EDT)
Message-Id: <200005311155.HAA25138@tantalum.atria.com>
From: "Geoffrey M. Clemm" <geoffrey.clemm@rational.com>
To: ietf-dav-versioning@w3.org
Subject: Re: Why do we need working resource ids ?
From: jamsden@us.ibm.com
Here's a couple of compelling use cases:
the server generated URLs are not likely to be in DAV
namespaces. That is, collection semantics won't work. They're only
to access one specific resource. The collection semantics do work
with the versioned resource and Target-Selector.
A revision id and working resource id don't give you any more
collection semantics than a revision URL or working resource URL, so I
don't see your point here. The collection semantics apply to the
human define versioned resource URL's, and that is true whether or not
you use revision URL's or revision id's to identify particular
revisions.
I am not yet compelled (:-).
Second, we need Target-Selector anyway for selecting revisions by
label, workspace, activity, perhaps baseline - all of which are
logical target selectors that have human meaningful names.
I agree that we should have a Target-Selector header that specifies
a label. I disagree that it should specify anything else.
We have the ability to select revisions by workspace ... just use
the URL of that workspace extended by whatever member of the workspace
you'd like to refer to (or use a Workspace header and a relative URL).
We have agreed (as recently as last week in Seattle :-) that we
would not allow an activity or a baseline in a Target-Selector header,
but rather require that a client merge that activity or baseline
to a workspace and then use that workspace. The reason is that
the caching opportunities provided by a workspace are required to
allow a server to efficiently perform activity or baseline
target selection.
We don't
want clients to have to use server generated URLs in some instances
and versioned resource and Target-Selectors in others in order to
use the more meaningful names. Personally, I think Target-Selector
will be used 99% of the time with either a label or workspace. The
server generated URLs will probably be rarely used.
I agree that a Target-Selector should be used to specify a label,
and that we have a Workspace header in which you can specify a workspace.
The question is whether we need revision-id's and working-resource id's.
But your reasoning above, it appears we do not, since 99% of the cases
use labels and workspaces, and the (rarely used) server generated
URL's can be used for the remaining 1% of the cases.
Cheers,
Geoff