Re: [sca-bindings] [Issue 2] Proposal version 3: How to implementSCA callbacks using SOAP

[Tom Rutt <tom@coastin.com>]

Mike Edwards wrote:
>
> Folks,
>
> I believe that what we previously decided regarding these descriptions 
> of how to implement specific
> capabilities of SCA using a given binding is that they would form 
> non-normative examples in an
> appendix in the relevant bindings specification.
I cannot see how Anish's proposal for implementing SCA callbacks using 
Soap and Ws Addressing
can work if it is only a non-normative example.

The proposal includes the following text:
"
The wsa:RelatesTo SOAP header block MUST have the relationship type 
value of "http://docs.oasis-open.org/opencsa/sca-bindings/ws/callback"; 
and the related message id is the wsa:MessageID of the message from 
which the Callback EPR was obtained.
"

This text registers a special value to use within the wsa:relatesTo 
element.   To Register this
special value requires it to be included in a normative part of the spec.

I like Anish's proposal, and do not see another way to do it with ws 
addresssing in use.

I think a better Idea is to have the text be in a normative part of the 
spec, but be considered an
optional compliance point which can be asserted by an implementation,
when sca is bound to wsdl/soap with ws addressing in this manner.

Tom Rutt
>
> So, the idea is that a proposal like Anish's would be ONE way of doing 
> callbacks with SCA over web
> services (SOAP), but would not rule out other ways of doing it.  What 
> it would show is that:
>
> a) there IS a way to implement the callback capability over web services
>
> b) the example will encourage implementers to provide callback in this 
> way and if so, then it would give
> a way to improve interoperability - if both ends implement according 
> to the example, they should interoperate.
>
>
> As for the @callback annotation for WSDL - the main purpose is for SCA 
> usage (to provide the same capability
> that we have in Java interfaces with the @callback annotation) - but 
> of course if a WSDL with such an annotation
> is encountered by a non-SCA web services client, that client can 
> choose to interpret it in the way that SCA defines....
>
> Yours,  Mike.
>
> Strategist - Emerging Technologies, SCA & SDO.
> Co Chair OASIS SCA Assembly TC.
> IBM Hursley Park, Mail Point 146, Winchester, SO21 2JN, Great Britain.
> Phone & FAX: +44-1962-818014    Mobile: +44-7802-467431  
> Email:  mike_edwards@uk.ibm.com
>
>
> From: 	Anish Karmarkar <Anish.Karmarkar@oracle.com>
> To: 	OASIS Bindings <sca-bindings@lists.oasis-open.org>
> Date: 	29/10/2008 23:58
> Subject: 	Re: [sca-bindings] [Issue 2] Proposal version 3: How to 
> implement SCA callbacks using SOAP
>
>
> ------------------------------------------------------------------------
>
>
>
> I forgot to mention that when this proposal is combined with Mike's idea
> of defining a WSDL extension to indicate the callback interface (similar
> to the @Callback Java annotation), what we have is a WS-Callback
> specification (I know, yet another WS-Splat spec). Such a spec could be
> a stand-alone spec independent of SCA and would result in non-SCA
> systems being able to talk to SCA services that offer bi-directional
> interfaces.
>
> -Anish
> --
>
> Anish Karmarkar wrote:
> > Attached.
> > I have converted the HTML version to Word, so that it is easy for folks
> > to comment and make inline changes.
> >
> > The big change between v2 and v3 is the addition of faults. My initial
> > inclination was to define our own faults, but it turns out 
> WS-Addressing
> > has some pre-defined faults which fit our purpose. So, I have reused
> > those faults.
> >
> > One thing I'm not clear on is whether the TC wishes to define this
> > SOAP-specific callback mechanism as *one* of the ways callbacks can be
> > implemented when using SOAP or *the* way callbacks are implemented when
> > using SOAP. My inclination is to say *the* way, otherwise we have to
> > invent ways (metadata such as policySets, ws-policy assertion, WSDL
> > extension, Java annotation) to convey when it is required.
> >
> > Comments?
> >
> > -Anish
> > --
> >
> >
> > ------------------------------------------------------------------------
> >
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-- 
----------------------------------------------------
Tom Rutt	email: tom@coastin.com; trutt@us.fujitsu.com
Tel: +1 732 801 5744          Fax: +1 732 774 5133