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Subject: Re: [wsrf] Comments on wsrf-ws_resource-1.2-spec-wd-07
+1
On 8 Sep 2005, at 12:53, Ian Robinson wrote:
>
>
>
>
> "Can one refer to a WS-Resource without a Resource identifier?"
> On the face of it this appears to be a simple question but in fact
> hides a
> degree of complexity, since the actual representation of the resource
> identifier is determined by the WS-Resource provider (i.e the creator
> of
> the EPR).
> The requirement WS-RF has is that the provider of a WS-Resource must be
> able to distinguish which specific resource should be used in the
> processing of the messages defined in the WS-RF specifications.
> Specifically, there must be enough information in the message for the
> WS-Resource-provider to be able to do this. We have just deleted text
> that
> made this requirement explicit on the grounds that it can be logically
> deduced that IF an EPR identifies exactly one WS-Resource then
> messages to
> the WS-Resource MUST contain (following the rules defined in
> WS-Addressing
> ) the information required for the WS-Resource to disambiguate the
> specific
> resource. However, we make no statement that an EPR MUST identify
> exactly
> one WS-Resource and so we have a problem.
>
> Previously the spec stated:
>
> A reference to a WS-Resource is represented by an endpoint
> reference, or
> more precisely an XML element whose type is, or is derived (by
> extension) from the complexType named EndpointReferenceType defined
> by
> the [WS-Addressing] specification.
>
> An identifier of the resource MUST be represented in any reference
> to a
> WS-Resource. and MUST appear as part of any message to a
> WS-Resource to
> allow the WS-Resource to disambiguate the resource targeted by the
> message. The precise location of the resource identifier in a
> message to
> a WS-Resource is dependent on the protocol binding used to interact
> with
> the WS-Resource endpoint but is normatively defined in the
> appropriate
> WS-Addressing binding specification. For example, [WSA – SOAP]
> defines
> the binding of message addressing properties for the SOAP protocol.
>
>
> and then we removed the 2nd bullet, which leaves us with a problem of
> under-specificity.
>
> We need to reinstate the requirement that this 2nd bullet conveyed.
> Perhaps
> the following single bullet would be better:
> A reference to a WS-Resource is represented by an endpoint
> reference, or
> more precisely an XML element whose type is, or is derived (by
> extension) from the complexType named EndpointReferenceType defined
> by
> the [WS-Addressing] specification. A reference to a WS-Resource
> encapsulates sufficient information to uniquely distinguish which
> resource should be used by the WS-Resource when it processes
> messages.
>
> There is no need for an upper case MUST in this because there is no
> interoperability issue - it is simply helping the reader to understand
> that
> WS-Addressing provides the appropriate mechanism for resource
> disambiguation required by WS-RF.
> If we go with the above, then the definition of "Resource Identifier"
> becomes redundant and could be removed.
>
> Regards,
> Ian Robinson
> STSM, WebSphere Messaging and Transactions Architect
> IBM Hursley Lab, UK
> ian_robinson@uk.ibm.com
>
>
>
> "Wilson, Kirk D"
> <Kirk.Wilson@ca.c
> om>
> To
> Ian Robinson/UK/IBM@IBMGB,
> "Murray,
> 07/09/2005 21:40 Bryan P." <bryan.murray@hp.com>
>
> cc
> <wsrf@lists.oasis-open.org>
>
> Subject
> RE: [wsrf] Comments on
> wsrf-ws_resource-1.2-spec-wd-07
>
>
>
>
>
>
>
>
>
>
> As I recall the previous discussion, the issue resolved around the
> normative MUST in "An identifier of the resource MUST be represented in
> any reference to a WS-Resource."
>
> The issue seems to be (and I don't pretend to be able to answer this
> question but would be VERY interested in the answer):
>
> Can one refer to a WS-Resource without a Resource identifier?
> If not, then use of an identifier is a necessity and not
> normative (small "must").
> If so, why are we requiring the use of an identifier? Is
> the
> use of an identifier necessary for interoperability, in which case it
> would be normative?
> If so and it is not necessary for interoperability, then
> it is
> a
> recommendation and we should probably say MAY (with a strong
> recommendation to do so).
>
> Kirk Wilson
> Architect, Development
> Office of the CTO
> 802 765-4337
>
>
> -----Original Message-----
> From: Ian Robinson [mailto:ian_robinson@uk.ibm.com]
> Sent: Wednesday, September 07, 2005 11:42 AM
> To: Murray, Bryan P.; Wilson, Kirk D
> Cc: wsrf@lists.oasis-open.org
> Subject: RE: [wsrf] Comments on wsrf-ws_resource-1.2-spec-wd-07
>
>
>
>
>
> One reason it is now difficult to relate the terms "resource
> identifier"
> and "reference to a WS-Resource" is that I removed (per the resolution
> to
> issue 127) the following text which related these 2 concepts:
> "An identifier of the resource MUST be represented in any reference to
> a
> WS-Resource. and MUST appear as part of any message to a WS-Resource to
> allow the WS-Resource to disambiguate the resource targeted by the
> message.
> The precise location of the resource identifier in a message to a
> WS-Resource is dependent on the protocol binding used to interact with
> the
> WS-Resource endpoint but is normatively defined in the appropriate
> WS-Addressing binding specification. For example, [WSA - SOAP] defines
> the
> binding of message addressing properties for the SOAP protocol."
>
> It is not clear to me that this text repeats any part of WS-Addressing
> -
> it
> is a description of the WS-RF usage of EPRs.
> I would agree with Kirk's observation and suggest that we reinstate
> some
> or
> all of the above text. At the very least, it would seem that we should
> still state: "An identifier of the resource MUST be represented in any
> reference to a WS-Resource. "
>
> Comments?
>
> Regards,
> Ian Robinson
> STSM, WebSphere Messaging and Transactions Architect
> IBM Hursley Lab, UK
> ian_robinson@uk.ibm.com
>
>
>
>
> "Murray, Bryan
>
> P."
>
> <bryan.murray@hp.
> To
> com> "Wilson, Kirk D"
>
> <Kirk.Wilson@ca.com>, Ian
>
> 06/09/2005 20:48 Robinson/UK/IBM@IBMGB,
>
> <wsrf@lists.oasis-open.org>
>
>
> cc
>
>
>
> Subject
> RE: [wsrf] Comments on
>
> wsrf-ws_resource-1.2-spec-wd-07
>
>
>
>
>
>
>
>
>
>
>
>
>
>
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>
>
> The reason ResourceIdentifier is NOT used is that an EPR does not
> provide "identity" for a resource. An EPR is only a reference to a
> resource.
>
> The use and rules associated with reference parameters is covered in
> WS-Addressing and should not be covered in this spec.
>
> Bryan
>
> -----Original Message-----
> From: Wilson, Kirk D [mailto:Kirk.Wilson@ca.com]
> Sent: Tuesday, September 06, 2005 12:08 PM
> To: ian_robinson@uk.ibm.com; wsrf@lists.oasis-open.org
> Subject: [wsrf] Comments on wsrf-ws_resource-1.2-spec-wd-07
>
> There now seems to be three concepts used with the space two pages:
>
> Resource Identifier
> Reference to a WS-Resource (which is structurally tied to
> WS-Addressing)
> And, in the SOAP example: SomeDisambiguatorElement
>
> These three concepts are never explicitly related to one other.
> Obviously, SomeDisabmiguator is part of the reference to a WS-Resource
> (ReferenceParameters). Further, I assume, after carefully trying to
> connect things that are in the text, that the Resource Identifier is at
> least one possible "disambiguator element". If so, would be clearer to
> use <ResourceIdentifier>R1</ResourceIdentifier> rather than
> <SomeDisambiguatorElement> in the example? After all, the text does say
> that "R1" "identifies" the resource
>
>
> Kirk Wilson
> Architect, Development
> Office of the CTO
> 802 765-4337
>
>
>
>
--
Take care:
Dr. David Snelling < David . Snelling . UK . Fujitsu . com >
Fujitsu Laboratories of Europe
Hayes Park Central
Hayes End Road
Hayes, Middlesex UB4 8FE
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