Fwd: Comments on Web Service Resource 1.2 wd 07

[David Snelling <David.Snelling@UK.Fujitsu.com>]

Folks,

This came to me directly with a request to post it. Enjoy.

Begin forwarded message:

> From: Mark McKeown <zzalsmm3@nessie.mcc.ac.uk>
> Date: 13 September 2005 13:35:35 BST
> To: David Snelling <David.Snelling@UK.Fujitsu.com>
> Cc: s.pickles@manchester.ac.uk
> Subject: Comments on Web Service Resource 1.2 wd 07
>
>
> Hi Dave,
>         I have had problems posting to the WSRF TC list in the
> past so I will send these comments to you - I have also made
> comments on the OGSA list as to why I think using
> ReferenceParameters by WS-Resource provides to map messages
> to state is bad - hope this is useful.
>
>
> Comments on Web Service Resource 1.2 wd 07
>
> Definition of "resource"
> ========================
>
> In the Requirements section there is the requirement to
> define the term "resource" - however the Normative
> References includes IETF RFC 2396 "Uniform Resource
> Identifiers (URI): Generic Syntax" which provides a
> definition of "resource", "A resource can be anything
> that has identity."
>
> The document does not explicitly reference the definition
> of "resource" given by RFC 2396 or say that it is extending
> that definition.
>
> The W3C Web Services Architecture [http://www.w3.org/TR/ws-arch/]
> also provides a definition of "resource" which extends
> the definition provided by by RFC 2396.
>
> a resource has
>       an identifier  (constrained to be a URI)
>
> a resource may have
>       zero or more representations
>
> a resource may have
>       zero or more resource descriptions
>
> a resource is owned by
>       a person or organization
>
> a resource may be governed by
>       zero or more policies
>
> The W3C Web Architecture [http://www.w3.org/TR/webarch/#id-resources]
> also uses the definition of "resource" provided by RFC 2396 - the
> document also recommends as good practice: "To benefit from and
> increase the value of the World Wide Web, agents should provide
> URIs as identifiers for resources." with the additional constraint
> that "Assign distinct URIs to distinct resources."
>
> The definition of "resource" in Web Service Resource 1.2
> wd 07, section 2.1 is inconsistent
> with the above, "A resource is a logical entity that has the
> following characteristics" - RFC 2396 allows a resource to be a
> physical entity to.
>
> From RFC 2396:
> "Not all resources are network "retrievable"; e.g., human beings,
> corporations, and bound books in a library can also be considered
> resources."
>
> (It is not clear what set of entities the qualifier 'logical' was
> ment to rule form the complete set of entities - I guessed
> physical)
>
> If you accept the definition of "resource" from RFC 2396 it
> makes the rest of Web Service Resource 1.2
> wd 07 hard to understand. For example the introduction to section
> 2 "The following terms are important to define the relationship
> between a Web service and one or more resources". A Web service
> CAN be identified by a URI - therefore it ISA resource.
> Should the sentence not read "The following terms are important
> to define the relationship between a Web service and OTHER resources"
>
>
> This concept of a Web service being a "resource" is also explicitly
> expressed in the W3C Web Service Architecture document, section
> 2.3.2.10:
> "A service is an abstract resource that represents a capability
> of performing tasks that represents a coherent functionality from
> the point of view of provider entities and requester entities. To
> be used, a service must be realized by a concrete provider agent."
>
>
> Compostion of a WS-Resource
> ===========================
> It is unclear to me why there is a need to describe how a WS-Resource
> is composed - for example the diagram in the document. The only way
> to test weither something is compliant with the WSRF specifications
> is to send it messages conformant to the WSRF spec and check the 
> response
> returned conforms to the WSRF specification. From the perspective
> of the client all they can see of the WS-Resource is the messages that
> are sent to it and recieved from it.
>
>
> cheers
> Mark
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Mark Mc Keown                            RSS
> Mark.McKeown@man.ac.uk 	                 Manchester Computing
> +44 161 275 0601     		         University of Manchester
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
>
>
-- 

Take care:

     Dr. David Snelling < David . Snelling . UK . Fujitsu . com >
     Fujitsu Laboratories of Europe
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