Subject: RE: WebDAV Bindings - Issue Yaron.MrIntegrity

From: "Clemm, Geoff" <[email-masked]>
Date: Wed, 22 Mar 2000 13:57:46 -0500

I propose that we delete all uses of the term "integrity" from
the spec, and instead say:

RFC 2518 allows resource deletion requests, such as DELETE and MOVE,
to do a "best effort" deletion on collections, where only some of
the members of the collection are deleted following the request.

In order to guarantee the more predictable BIND/UNBIND semantics when a
binding
unaware client is used to do authoring on a binding aware server,
a binding aware server is required to map deletion requests into the
appropriate UNBIND request.

More formally: If a DELETE request, MOVE request, or a request with an
Overwrite:T header is applied to a resource identified by the URL
/path/x, and /path identifies a collection that supports the BIND/UNBIND
methods, then the request MUST have the same effect as an UNBIND of x from
/path.
In particular, if the request succeeds, the binding named x MUST be removed
from the collection indentified by /path, and whether or not the request
succeeds, no other bindings from any other collection may be removed.

As a corollary to this rule, if a DELETE request, MOVE request,
or a request with an Overwrite:T header is applied to a collection
identified by the URL /path1, then a resource identified by the URL
/path1/path2/path3 MUST NOT be deleted if /path1/path2 supports the
BIND/UNBIND operation.

Cheers,
Geoff

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]On
Behalf Of Yaron Goland
Sent: Sunday, January 16, 2000 8:49 PM
To: [email-masked]
Subject: WebDAV Bindings - Issue Yaron.MrIntegrity

The last sentence of the last paragraph of section 4 reads "Implementations
MUST ensure the integrity of bindings." Similar language is used in the
second paragraph of section 5.1. However the term "integrity" was never well
defined inside of the specification. As such it is impossible to comply with
this requirement in an interoperable way. I would strongly caution against
attempting to specify the definition for integrity, English is much too
inexact a language for such an attempt to be successful.
        As such, I move that both sentences be removed and be replaced with
a series of statements that define, in exact language, the requirements that
are to be represented by the term "integrity", each sentence properly
qualified with a MUST.

---

From: "Slein, Judith A" <[email-masked]>
Date: Mon, 27 Mar 2000 15:26:37 -0500

This looks like most of what we want for guaranteeing integrity of bindings.

What we want to avoid is a situation where a binding might be broken or
removed as a side effect of an operation on some other binding.  We don't
want a URI to stop working as a result of a DELETE or MOVE operation
submitted to a different Request-URI.

The sort of case we initially considered when talking about integrity is not
entirely covered by your proposed language: Suppose you have two separate
servers (or two parts of the namespace of one server that are separately
managed) and you create a binding from a location on one server to a target
resource on the other.  Then unless you had some out-of-band way of
collaborating on the creation of this new binding, the server managing the
target resource would not know that this binding had been created.  Then
when the last binding it knows about is deleted, it will be free to destroy
the resource, and the binding on the other server may be broken.  The server
can be obeying the rules you state in your message (as far as it knows) and
still do something that will cause the binding to be broken.

So we need to address some constraints to the server that allowed the
binding to be created in the first place -- it should never have allowed the
binding to be created unless it had some way to communicate the existence of
the binding to the server managing the target resource.

--Judy

-----Original Message-----
From: Clemm, Geoff [mailto:[email-masked]]
Sent: Wednesday, March 22, 2000 1:58 PM
To: [email-masked]'
Subject: RE: WebDAV Bindings - Issue Yaron.MrIntegrity

Cheers,
Geoff