Just so that I'm clear, is it true that any given:
[HTTP req msg + MC] --> Service
could be answered by any one of:
[HTTP res msg + callback req] <-- Service
OR
[HTTP res msg (2xx) + empty entity body] <-- Service
The response for req msg is ONLY obtained by: what's in the ???? empty body+MC headers? Same as first message?
[HTTP req msg + ????] --> Service
[HTTP res msg (2xx) + resp msg] <-- Service
Dave Booz
STSM, BPM and SCA Architecture
Co-Chair OASIS SCA-Policy TC and SCA-J TC
"Distributed objects first, then world hunger"
Poughkeepsie, NY (845)-435-6093 or 8-295-6093
e-mail:
Anish Karmarkar ---03/05/2009 04:11:13 AM---Simon Nash wrote: > See comments inline.
From:
Anish Karmarkar <>
To:
Simon Nash <>
Cc:
OASIS Bindings <>
Date:
03/05/2009 04:11 AM
Subject:
Re: [sca-bindings] Issue 2: proposal v11
Simon Nash wrote:
> See comments inline.
>
> Simon
>
> Anish Karmarkar wrote:
>> Eric Johnson wrote:
>>> There's one point that I tripped on. At the very end, with the example
>>> using "WS-MakeConnection", you say:
>>>
>>> "3) Callback request message (from the service to the reference) sent as
>>> a “response” to MakeConnection" - Doesn't it need to be simply "callback
>>> message (from the ..." - I don't see an opportunity for a
>>> request/response exchange here."
>>>
>>
>> The reason "response" is in quotes is because this would be a response
>> at the transport/transfer protocol level. When using HTTP, the
>> MakeConnection SOAP messages is sent with the HTTP request, the SCA
>> callback request message is sent back on the HTTP response.
>>
>>> Do we need to flag, at the first introduction of WS-MakeConnection, that
>>> it can only be used for one-way operations on the callback interface?
>>>
>>
>> It can be used with a WSDL req-response operation on the callback
>> interface. This is similar to how WSDL req-res operation works when
>> the wsa:ReplyTo is non-anonymous. In the case of req-res SCA callback
>> operation, the message exchange will consists of 2 separate HTTP
>> connection as follows:
>>
>> 1.1) Reference --> [HTTP req msg + MC] --> Service
>> 1.2) Reference <-- [HTTP res msg + callback req] <-- Service
>>
>> 2.1) Reference --> [HTTP req msg + callback res] --> Service
> >
> How does the service know that this message contains a callback response
> rather than a new service request?
The payload should tell the service that.
Plus you have wsa:Action wsa:RelatesTo and wsa:RefPs.
>
>> 2.2) Reference <-- [HTTP res msg (2xx) + empty entity body] <-- Service
>>
> What if the original service request is request/response? This messsage
> would need to carry the response to that request, not an empty entity body.
> Is this possible?
>
Not when using WS-MC.
The original service request's wsa:ReplyTo will have to be respected.
That wsa:ReplyTo would be a WS-MC anonymous, which would require the
service to send the response to the original request as a response to a
MC request.
> Another possibility is that the service sends a second callback request.
> I presume this is OK, and that it would be addressed to the same
> MC endpoint as the first callback request.
>
Yes, in theory.
But in practice, this would be an interop nightmare, I would think. The
reference component would have to expect such a piggy-backed 2nd
callback request and process it. Since this wasn't a HTTP response to a
MC request, it may not have expected this message and may not process it.
> To clarify what happens for all these cases, I think we need to add some
> interaction flow diagrams (similar to the above) for all the one-way and
> req-res combinations.
>
Hmm. I don't know, since we don't write WS-* specs (although we do write
specs that walk and quack like it), don't you think having the
WS-Callback stuff be longer than the binding.ws part would be a problem? ;-)
-Anish
--
> Simon
>
>> -Anish
>> --
>>
>>> -Eric.
>>>
>>> Anish Karmarkar wrote:
>>>> Thanks for the comments. Mostly agree with all of them.
>>>>
>>>> -Anish
>>>> --
>>>>
>>>> Simon Nash wrote:
>>>>> Anish,
>>>>> My comments are inline in the attached document.
>>>>>
>>>>> Simon
>>>>>
>>>>> Anish Karmarkar wrote:
>>>>>> Attached.
>>>>>>
>>>>>> I accepted changes from v10 and made additional changes as I was
>>>>>> tasked to do during the last call. This should address all the
>>>>>> comments/issues so far except for one, which is the name of the
>>>>>> WS-Policy assertion.
>>>>>>
>>>>>> I have changed it from sca:CallbackAssertion to sca:WSCallback. My
>>>>>> rationale for this is:
>>>>>> 1) 'Assertion' is redundunt, so removal just makes it shorter and
>>>>>> shorter is better.
>>>>>> 2) This is a callback mechanism that is defined for Web services.
>>>>>> Other bidnings/technologies that are used in SCA may have a
>>>>>> different mechanism for callback so the previx 'WS' makes sense.
>>>>>> This constrains it to the realm of Web services.
>>>>>>
>>>>>> The other suggestion that was made by Mike was
>>>>>> sca:CallbackAssertion_WSA. I prefer a WS (or WSA) prefix rather than
>>>>>> a suffix and the underscore is unnecessary. So I suppose another
>>>>>> alternative would be 'sca:WSACallback'.
>>>>>>
>>>>>> -Anish
>>>>>> --
>>>>>>
>>>>>>
>>>>>> ------------------------------------------------------------------------
>>>>>>
>>>>>>
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