Notes from 5/3/99 Versioning TeleConf
Geoffrey M. Clemm (gclemm@tantalum.atria.com)
Mon, 3 May 1999 16:39:58 -0400
Date: Mon, 3 May 1999 16:39:58 -0400
Message-Id: <9905032039.AA06833@tantalum>
From: "Geoffrey M. Clemm" <gclemm@tantalum.atria.com>
To: ietf-dav-versioning@w3.org
Subject: Notes from 5/3/99 Versioning TeleConf
- Configurations
There was basic agreement with the proposed approach to configurations,
but the following issues were still outstanding:
Jim Amsden suggested that we replace the DAV:scope property with a
collection that is bound to the versioned-resources that would have
been listed in the DAV:scope property.
I personally think this is a good idea, because a binding is a more
stable locating mechanism than a URL. We would still need some property
containing a list of URL's to allow cross-server configurations (since
cross-server bindings are unlikely to be supported by many servers).
Jim further suggested that the configuration revision actually *be* this
collection.
I'm a little more hesitant about that, since I'm concerned that there
will be other "collections" that we will want to associate with a
configuration revision. I don't have anything particular in mind yet,
but I'm still concerned that something will turn up.
We then discussed the "create a configuration revision without using
a workspace" issue. Chris indicated that the "configuration workspace"
described in the agenda makes sense, but is concerned that there are
complexities associated with introducing another flavor of workspace,
since we already have "checkout-token workspaces" and "version-selection
workspaces".
Jim Amsden suggested that we just allow a list of revisions to be
specified when creating the configuration revision. My concern with
this approach is that the server should confirm that the list of
revisions is a "legal" configuration (e.g. that it specifies at most
one revision of each versioned-resource, and that it selects a
revision of each internal member of a collection revision), and that
many servers will need a workspace to perform this computation efficiently.
An alternative approach is to let the client specify a label to be used
to pick revisions that should go into the configuration revision, but
this requires the client to actually put a label on all revisions to
go in the configuration, and requires the server to scan every
versioned-resource in the configuration to see what revision the
label would select.
- Repositories
The next topic was a "repository" resource.
The purpose of a repository is to provide browse access to all the
versioning meta-data, such as versioned-resources, activities, and
workspaces. Although it is feasible to eventually locate most
information by following the graph of inter-object references, since
there are an infinite number of paths through this cyclic graph,
some mechanism that indexes the key resource types in an interoperable
way is very important.
The repository resource provides such a mechanism. In particular, the
repository is a collection which contains at least four standard
subcollections, named "activity", "versioned-resource",
"configuration", and "workspace". A member of the versioned-resource
or configuration collections would have a server-generated
versioned-resource-id as its name, while an activity or workspace
would have a client specified name.
The repository also provides a convenient mechanism for naming versioning
metadata in a way that is accessible to non-versioning-aware clients.
The "property-collection" proposal was a way to avoid picking specific
names for these subcollections, but rather have the names of the subcollections
be specified as properties of the repository. Jeff McAffer suggested
that this level of naming flexibility is not needed, and the group agreed.
- Details for Upcoming Design Team Meeting
Dates: May 26-27
Sponsor: Rational Software
Location: Concord's Colonial Inn, Concord, MA
Phone: 978-369-9200
Room Rate: $125/night
Room Reservation Deadline: May 14, 1999
Nearest Major Airport: Boston Logan
Directions from Boston:
Sumner Tunnel
to Rte. 93N
to Rte. 95S exit
to Exit 29B (West Rte. 2)
follow signs for Concord Center
to Monument Sqare.
Note: The rooms at the Colonial Inn will probably disappear by May 15,
so reserving early is recommended.
Cheers,
Geoff