Re: [ws-rx] Anon / RM MakeConnection: [reply ep] = none

Alastair Green <alastair.green@choreology.com> wrote on 08/09/2006 
05:33:12 AM:
> Paul,
> 
> I don't think that the behaviour I describe (where RM knowledge 
> intrudes into a WS-Addressing implementation of a core WS-Addressing
> feature) is acceptable. This is a composition/layering problem.
> 
> WS-A impl must now apply special rules (as I have described) if it 
> encounters a message with [reply ep] = none which happens to be a 
> WS-RM message called MakeConnection. Do you agree with that statement? 

Per the WSA spec, 'none' is defined as:
---
Messages sent to EPRs whose [address] is this value MUST be discarded 
(i.e. not sent). This URI is typically used in EPRs that designate a reply 

or fault endpoint (see section 3.1 Abstract Property Definitions) to 
indicate that no reply or fault message should be sent.
---
So, let's assume the MC has a replyTo set to none.
I hope we agree that any messages targeted to that EPR should be 
discarded - per the above text from WSA. So, the question is, what
messages are targeted to that EPR?  From the MC perspective _none_.
Since MC is a one-way there is no defined response. At this point
the receiver of the MC is then free to do one of two things:
1 - return a 202, or
2 - reuse the http response flow to send a message

Step 2 is no different, as Paul said in a previous note, from how
RM already allows for Acks to be sent back in cases where normally
an HTTP 202 would be sent.
Alastair - you need to understand that MC does not generate a 
response.  You may not like it, but that is how it is defined.

> If so, how would you go about creating a freestanding WS-A Core 
> implementation that is RM-unaware?
> 
> WS-TX decided to make all one-ways have [reply ep] = none, to make 
> clear that its notification messages are indeed "one way". I don't 
> see any problem with that. 
> 
> However, these MakeConnection messages are not the same. They 
> induce, in the broad, the back channel behaviour created by use of 
> anon. But they are subtly different, in that the response may just 
> be an ack. There is no well-known URI to represent that behaviour, 
> at present (or at least, the RM one is not being used).
> 
> At best, this is an RM extension to WS-Addressing, and it should 
> layer cleanly on the WS-Addressing core behaviour.
> 
> Alastair