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Subject: Re: [wsrf] Groups - wsrf-ws_resource-1.2-spec-wd-08.doc uploaded (fwd)
Mark et al,
Another posting from Mark. I will answer in line at the same time as
posting.
First wrt your earlier mail, a lot of the issues surrounding the notion
of what a resource is have been addressed in the recent drafts. What a
resource actually can be is much the same as the W3C model. However,
all the semantic around WSRF focus on the WS-Resource and the
associated MEPs. Have a look during our final Public review (starting
this afternoon hopefully).
On 15 Sep 2005, at 20:51, Mark McKeown wrote:
>
> Hi Dave,
>
> Afraid I bounced again - I have got e-mails saying
> I am part of the TC!
>
> If my input starts to be a hindrence rather than a help
> let me know and I will stop - I cannot tell from the
> postings on the list if the TC wants to move on...
>
> cheers
> Mark
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Mark Mc Keown RSS
> Mark.McKeown@man.ac.uk Manchester Computing
> +44 161 275 0601 University of Manchester
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> ---------- Forwarded message ----------
> Date: Thu, 15 Sep 2005 20:45:22 +0100 (BST)
> From: Mark McKeown <zzalsmm3@nessie.mcc.ac.uk>
> To: "Wilson, Kirk D" <Kirk.Wilson@ca.com>
> Cc: ian_robinson@uk.ibm.com, wsrf@lists.oasis-open.org
> Subject: RE: [wsrf] Groups - wsrf-ws_resource-1.2-spec-wd-08.doc
> uploaded
>
>
> +1 to the comments by Kirk, they were things that confused me
> on reading wd 08.
>
> I have some futher comments to add regarding the use of the
> EPR in the example included in wsrf-ws_resource-1.2-spec-wd-08.doc:
>
> <wsa:EndpointReference>
> <wsa:Address>
> http://www.example.com/service
> </wsa:Address>
> <wsa:ReferenceParameters>
> <tns:SomeDisambiguatorElement>R1</tns:SomeDisambiguatorElement>
> </wsa:ReferenceParameters> ?
> .
> </wsa:EndpointReference>
>
>
> Given this EPR the client does not know weither the
> SomeDisambiguatorElement element is being used to
> identify him, ie the client, or being used to map
> messages to state by the service provider.
> (ReferenceParameters are supposed to be opaque - so
> he shouldn't be looking anyway)
The example is just for guidance. The EPR is opaque. We even discussed
something like:
> <wsa:ReferenceParameters>
> <tns:ghfhrd>ggdtsr53674534</tns:ghfhrd>
> </wsa:ReferenceParameters> ?
But it didn't seem to make things any clearer.
> From my understanding of ReferenceParameters they
> are similar to HTTP cookies ie. they are used to
> support stateful interactions.
>
> So a client who is given a EPR that contains
> ReferenceParameters should not share the EPR as
> the ReferenceParameters may be client specific,
> ie they might be used by the service provider
> to identify which client sent the message.
> So EPRs with ReferenceParameters should not be put
> into public or shared ServiceGroups/registries, just
> as bad things can happen if you share your cookies.
I don't see a problem here. If as a client I have put an RP in the EPR,
this one is not opaque and I can remove it before storing it in a
registry. RP's have many functions, some opaque and not.
> I think this is why the W3C think that cookies
> should not be used to identify resources as it reduces
> the visibility of the system.
This is one of the advances that WS-Addressing adds. At present many
URI/HTTP based systems use cookies to identify the resource at the end
of an http request, i.e. bunches of identification data not in the URI
- so much for the pure URI model. The WS-A EPR actually helps this
problem by providing a standard wrapper for all this stuff.
> Am I mistaken. Should the WSRF TC recommend that WS-Resource
> implementors not use ReferenceParameters to map messages
> to particular state?
I think this is an implementation choice. I know of several
implementations that don't use the RPs - others that do.
> (I believe this is an issue that Hugo Haas raised in
> the WS-Addressing WG -
> http://lists.w3.org/Archives/Public/public-ws-addressing/2004Dec/0051)
>
>
> Is the use of EPRs as references to WS-Resources mandatory -
> ie. should the word MUST be used. (Currently only a SOAP binding
> has been defined for WS-Addressing - ie HTTP and Plain Old XML
> cannot be used to implement WSRF using EPRs)
This is an interoperability issue. Eventually there will be other WS-A
bindings.
>
> cheers
> Mark
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Mark Mc Keown RSS
> Mark.McKeown@man.ac.uk Manchester Computing
> +44 161 275 0601 University of Manchester
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> On Thu, 15 Sep 2005, Wilson, Kirk D wrote:
>
>> As someone said earlier, this is a "black hole". I apologize, the
>> conversation on this doc went a little too fast and was not all that
>> audible for me to jomp in on the telephone. I was thinking about the
>> text and you had moved onto the BaseFaults discussion.
>>
>> Two things:
>> 1. The third bullet says: "If access to the lifecycle of the
>> resource
>> is exposed through the WS-Resource, ..." I thought there was a
>> clarification given earlier in the day that the lifecycle of the
>> resource is NOT that which is exposed through WS-RL--just the
>> lifecycle
>> (Destroy) of the WS-Resource. We really can't infer anything about
>> the
>> lifecycle of the resource. This statement should be rephrased to be
>> consistent with the clarification.
>>
>> 2. I find the diagram in 2.2.1 confusing because it is incomplete.
>> It
>> shows a single Web service and two resources. However, it doesn't
>> have
>> any representation of the "WS-Resource" associated with the Web
>> service
>> and the resource identified by R1. Is the Ws-Resource in 1:1
>> association with the Web Service and 1:m with the resources? Or is
>> the
>> Web service in 1:m association with WS-Resources, each of which has a
>> 1:1 association with the resources? (I believe the answer is the
>> later,
>> but neither the diagram nor the text makes these associations clear.
>> Note, as well, that the text says "The Web service provides access to
>> two resources..." That's the role of the WS-Resource, which, IMHO,
>> further confuses the discussion.
>>
>> Sorry for the delay in getting you these comments.
>>
>> Kirk Wilson
>> Architect, Development
>> Office of the CTO
>> 802 765-4337
>>
>> -----Original Message-----
>> From: ian_robinson@uk.ibm.com [mailto:ian_robinson@uk.ibm.com]
>> Sent: Thursday, September 15, 2005 11:39 AM
>> To: wsrf@lists.oasis-open.org
>> Subject: [wsrf] Groups - wsrf-ws_resource-1.2-spec-wd-08.doc uploaded
>>
>> The document named wsrf-ws_resource-1.2-spec-wd-08.doc has been
>> submitted
>> by Dr Ian Robinson to the OASIS Web Services Resource Framework (WSRF)
>> TC
>> document repository.
>>
>> Document Description:
>> WS-Resource spec - wd-08
>>
>> View Document Details:
>> http://www.oasis-open.org/apps/org/workgroup/wsrf/document.php?
>> document_
>> id=14466
>>
>> Download Document:
>> http://www.oasis-open.org/apps/org/workgroup/wsrf/download.php/14466/
>> wsr
>> f-ws_resource-1.2-spec-wd-08.doc
>>
>>
>> PLEASE NOTE: If the above links do not work for you, your email
>> application
>> may be breaking the link into two pieces. You may be able to copy and
>> paste
>> the entire link address into the address field of your web browser.
>>
>> -OASIS Open Administration
>>
>
>
>
>
>
--
Take care:
Dr. David Snelling < David . Snelling . UK . Fujitsu . com >
Fujitsu Laboratories of Europe
Hayes Park Central
Hayes End Road
Hayes, Middlesex UB4 8FE
+44-208-606-4649 (Office)
+44-208-606-4539 (Fax)
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