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RE: Optional discussion

From: Yalcinalp, Umit <umit.yalcinalp@sap.com>
Date: Wed, 2 Aug 2006 15:29:11 -0700
Message-ID: <2BA6015847F82645A9BB31C7F9D6416501D5ED86@uspale20.pal.sap.corp>
To: "William Henry" <william.henry@iona.com>, <public-ws-policy@w3.org>


I surely do not want to miss your points on this very issue. I was under
the assumption that bug creation would kick off the email thread and
folks would be able to reply to it. We would then be able to point to
the discussion. Apparently my assumption was incorrect. 

Since there appears to be an issue with the issue tracking system ;-),
let me create a separate thread on this so we capture the discussion
specific to the optional assertions. 



> -----Original Message-----
> From: William Henry [mailto:william.henry@iona.com] 
> Sent: Wednesday, Aug 02, 2006 2:12 PM
> To: public-ws-policy@w3.org
> Cc: Yalcinalp, Umit
> Subject: Optional discussion
> Hi Umit et al,
> I'd like to comment on Umit's earlier discussion on the usage on the  
> optional tag. From what I understand Umit is raising the 
> issue around  
> what is the expected behavior when a client initiates a request to a  
> service that has some policy as optional. Specifically should the WG  
> specify the expected behavior in the Framework or Primer.  I think  
> Umit raises a good point. (If of course I understand the issue  
> correctly)
> [If this is the wrong way to discuss this please let this 
> novice know  
> the right way]
> At the endpoint level:
> The example that seems to be bantered about is regarding MTOM.  
> Suppose the MTOM is optional. The client knows MTOM and initiates a  
> request using MTOM. Surely it is a fair enough assumption that the  
> server would reply using MTOM. I would assume that on an optional  
> policy the initiator then decides the conversation. And so from then  
> on, in the conversation, all is MTOM. If the client decides to use  
> the service again and initiates without using MTOM then the server  
> should assume that they are not using MTOM (and should assume that  
> they can't or do not want to) and therefore reply appropriately. (I  
> know if I am shopping and someone makes a service claim as an option  
> and I intend to us it then I expect them to behave a certain way -  
> e.g. advertising that they take AmEX  and then refusing my AmEx card  
> is NOT good behavior unless of some extra circumstances)
> At the message level it seems to me that it would be in very poor  
> taste for a service to have defined optional on the inbound and  
> required on the outbound - when you're talking about transports/ 
> protocols etc. e.g. optional encryption on the inbound message and  
> then require it on the outbound. Why would someone design their  
> interface like this? And surely the client would see the 
> assertion on  
> the outbound and go look for this service elsewhere. And if it's  
> optional on the inbound and the client doesn't use it then the same  
> behavior of client-is-right holds.
> I'm bet I'm missing some other examples or points here. Am I missing  
> some more complicated issues? But I do think Umit raises a 
> good point  
> about documenting some best practices at the very least about 
> the use  
> of optional.
> The good news is that practitioners will very quickly come to some  
> understanding about this when their services don't get used :-)
> But should the WG have something to say on the matter? Either  
> recommendations or requirements?
> Please let me know if I'm supposed to be logging this elsewhere. In  
> bugzilla under Umit's issue? Some of you kind folks will put me  
> right! :-)
> Regards,
> William
Received on Wednesday, 2 August 2006 22:26:11 UTC

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