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Re: Mandator wsa:Action (was Re: WS-Addr issues)

From: Mark Little <mark.little@arjuna.com>
Date: Fri, 5 Nov 2004 08:47:39 +0000
Message-Id: <5964D586-2F07-11D9-84E9-00039399DACE@arjuna.com>
Cc: Francisco Curbera <curbera@us.ibm.com>, David Orchard <dorchard@bea.com>, public-ws-addressing@w3.org
To: Marc Hadley <Marc.Hadley@Sun.COM>

+1

The presence of an opcode, sequence number, or whatever in a message 
sent from A to B does not by itself give an external observer the 
ability to distinguish RPC versus asynchronous message passing, for 
example. It's higher level processing semantics that do that and even 
then there's no grand architectural tenant for RPC that says "thou must 
place an opcode in this location to be RPC". I've been dealing with RPC 
systems (and written a few) since the mid 80's, and if there is such a 
rule I haven't seen it.

Mark.

On 4 Nov 2004, at 19:35, Marc Hadley wrote:

> On Nov 4, 2004, at 12:33 PM, David Orchard wrote:
>>
>> The real problem is the same problem we had with the optional soap 1.1
>> action http header.  Software can't count on it being there, so they 
>> end
>> up looking inside the body as "the one true and certified source of
>> action" which effectively pushed everybody into RPC land.
>
> I think the association between looking at the payload of a message 
> and RPC is false. One could just as easily argue that requiring an 
> action is *more* RPC-like where action==method and message 
> payload==method parameters.
>
> RPC is in the eye of the beholder, its not defined by the presence or 
> lack of an action.
>
> Marc.
>
>>   This happened
>> because all the toolkits had to support at least looking in the body 
>> and
>> then not all did the look at action and thus the world was a worse
>> place.
>>
>> I predict that an optional WSA:Action will have the same effect IF 
>> there
>> is no mandatory/normative way of generating a WSA:Action infset 
>> property
>> from any binding that hasn't serialized the WSA:Action as a soap 
>> header
>> block.
>>
>> I don't want to live in the message bodies always contain the verb 
>> world
>> any more.
>>
>> Dave
>>
>>> -----Original Message-----
>>> From: Mark Little [mailto:mark.little@arjuna.com]
>>> Sent: Thursday, November 04, 2004 9:24 AM
>>> To: David Orchard; Francisco Curbera
>>> Cc: public-ws-addressing@w3.org; public-ws-addressing-request@w3.org
>>> Subject: Mandator wsa:Action (was Re: WS-Addr issues)
>>>
>>> David, I changed the subject line - you're right in that regard.
>>>
>>> As for keeping wsa:Action mandatory, I think you're wrong ;-)
>>>
>>> What is the real problem with making this optional? What would break
>> as a
>>> result?
>>>
>>> Mark.
>>>
>>> ----
>>> Mark Little,
>>> Chief Architect,
>>> Arjuna Technologies Ltd.
>>>
>>> www.arjuna.com
>>>
>>> ----- Original Message -----
>>> From: "David Orchard" <dorchard@bea.com>
>>> To: "Francisco Curbera" <curbera@us.ibm.com>; "Mark Little"
>>> <mark.little@arjuna.com>
>>> Cc: <public-ws-addressing@w3.org>;
>> <public-ws-addressing-request@w3.org>
>>> Sent: Thursday, November 04, 2004 4:40 PM
>>> Subject: RE: WS-Addr issues
>>>
>>>
>>>> +1.
>>>>
>>>> Arguing against action is like arguing against HTTP operations.
>> Having
>>>> one spot for Action will give all WS-A applications a much simpler
>>>> processing model and enable a doc/literal world.
>>>>
>>>> Separately, can we pick better subject lines and focus the
>> conversation
>>>> a bit?  I think this thread is on mandatory Action.  I expect we are
>>>> going to debate every single component's mandatory/optional nature
>> and
>>>> separating them would help a lot.
>>>>
>>>> Dave
>>>>
>>>>> -----Original Message-----
>>>>> From: public-ws-addressing-request@w3.org
>>>> [mailto:public-ws-addressing-
>>>>> request@w3.org] On Behalf Of Francisco Curbera
>>>>> Sent: Thursday, November 04, 2004 6:26 AM
>>>>> To: Mark Little
>>>>> Cc: public-ws-addressing@w3.org;
>> public-ws-addressing-request@w3.org
>>>>> Subject: Re: WS-Addr issues
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> The idea that the intent of the message is *always* embedded in
>> the
>>>> body
>>>>> of
>>>>> the message smells like SOAP-RPC in sheep clothes to me. I am not
>>>> saying
>>>>> that will never be the case, but you need to allow for the case in
>>>> which
>>>>> the same document type is used in different interactions - for
>>>> example, a
>>>>> customerInfo document could be sent as input to both an "update"
>> and a
>>>>> "create" operations.This "document centric" model is actually very
>>>>> frequent
>>>>> (it is no uncommon in CICS applications for example). To support
>> this
>>>>> model
>>>>> you need either an Action header or something functionally
>> equivalent.
>>>>>
>>>>> Paco
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>                       "Mark Little"
>>>>>                       <mark.little@arjuna.com>        To:
>>>> "Sanjiva
>>>>> Weerawarana" <sanjiva@watson.ibm.com>,
>> <public-ws-addressing@w3.org>
>>>>>                       Sent by:                        cc:
>>>>>                       public-ws-addressing-req        Subject:
>> Re:
>>>> WS-
>>>>> Addr issues
>>>>>                       uest@w3.org
>>>>>
>>>>>
>>>>>                       11/04/2004 05:05 AM
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> Hi Sanjiva. Although not an answer to your question, I think it's
>>>> worth
>>>>> bringing up generally: personally I think wsa:Action should be
>> dropped
>>>> or
>>>>> made optional. Why have an "op code" (which is essentially what it
>> is)
>>>>> embedded in an address? I can see that there are optimizations
>> that
>>>> could
>>>>> be made to dispatching directly on the Action rather than having
>> to
>>>> parse
>>>>> the body, but surely that's an implementation specific issue? I'd
>> be
>>>>> interested in knowing how many users of WS-Addressing actually use
>>>> this
>>>>> versus those that ignore it.
>>>>>
>>>>> Mark.
>>>>>
>>>>> ----
>>>>> Mark Little,
>>>>> Chief Architect,
>>>>> Arjuna Technologies Ltd.
>>>>>
>>>>> www.arjuna.com
>>>>> ----- Original Message -----
>>>>> From: Sanjiva Weerawarana
>>>>> To: public-ws-addressing@w3.org
>>>>> Sent: Wednesday, November 03, 2004 7:42 PM
>>>>> Subject: Re: WS-Addr issues
>>>>>
>>>>> Hi Steve,
>>>>>
>>>>> What's your view of dispatching with wsa:Action? Since those are
>>>> required
>>>>> to be unique that gives enough info to find the operation to
>> dispatch
>>>>> to within a service. The service itself is of course identified
>> from
>>>>> the <To> somehow.
>>>>>
>>>>> Sanjiva.
>>>>>  ----- Original Message -----
>>>>>  From: Vinoski, Stephen
>>>>>  To: Doug Davis
>>>>>  Cc: public-ws-addressing@w3.org
>>>>>  Sent: Thursday, November 04, 2004 12:58 AM
>>>>>  Subject: RE: WS-Addr issues
>>>>>
>>>>>  +1 to having a pointer to the WSDL itself in the EPR. We have
>> found
>>>> in
>>>>>  working with our customers that having access to the service
>>>> definition
>>>>> is
>>>>>  critical for applications that rely on pure dynamic dispatching.
>>>>>
>>>>>  --steve
>>>>>        -----Original Message-----
>>>>>        From: Doug Davis [mailto:dug@us.ibm.com]
>>>>>        Sent: Wednesday, November 03, 2004 11:02 AM
>>>>>        To: public-ws-addressing@w3.org
>>>>>        Subject: WS-Addr issues
>>>>>
>>>>>
>>>>>        I might have missed a formal request for "issues" from the
>>>> public
>>>>>        but since it appears there is now an issues list I thought
>> I'd
>>>> make
>>>>>        some suggestions on possible issues for the WG's
>> consideration:
>>>>>
>>>>>        issue: EPRs have WSDL bits - e.g. PortType, ServiceName.
>> But
>>>> no
>>>>>        pointer to the actual WSDL itself - why not?  W/o the WSDL
>> do
>>>> these
>>>>>        values mean anything?  And if we assume the consumer of the
>> EPR
>>>> has
>>>>>        the WSDL why can't we assume they know the PortType and
>>>>> ServiceName?
>>>>>        Perhaps an example of how this would be used would clarify
>> it
>>>> for
>>>>>        me.
>>>>>
>>>>>        issue: If a response message is expected then a wsa:ReplyTo
>>>> MUST be
>>>>>        included.  Does the absence of a wsa:ReplyTo imply a
>> one-way
>>>>>        message?  The spec seems to come very close to saying that.
>>>> And
>>>>>        does the presence of wsa:ReplyTo imply a two-way message?
>> My
>>>>>        preference would be to have a clear statement so that upon
>>>>>        inspection of the message itself a processor can know if
>> its a
>>>>>        one-way or two-way w/o having to go back to the wsdl.
>>>>>
>>>>>        issue: wsa:FaultTo:  "This property may be absent if the
>> sender
>>>>>        cannot receive fault messages (e.g. is a one-way
>> application
>>>>>        message)."  But it also says that in the absence of
>> wsa:FaultTo
>>>> the
>>>>>        wsa:ReplyTo/From may be used.  So, how does a client really
>> say
>>>>> that
>>>>>        it doesn't want ANY fault messages at all but still be
>> allowed
>>>> to
>>>>>        specify a wsa:From?
>>>>>
>>>>>        thanks
>>>>>        -Doug
>>>>>
>>>>
>>>>
>>
>>
>>
> ---
> Marc Hadley <marc.hadley at sun.com>
> Web Technologies and Standards, Sun Microsystems.
>
Received on Friday, 5 November 2004 09:06:11 GMT

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