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Re: Comment on WSDL spec: use of Anonymous Element

From: Alastair Green <alastair.green@choreology.com>
Date: Fri, 04 Aug 2006 11:59:46 +0100
Message-ID: <44D328A2.6040408@choreology.com>
To: Doug Davis <dug@us.ibm.com>
CC: public-ws-addressing@w3.org, ws-rx@lists.oasis-open.org

Doug,

This is probably a dumb question, but aren't you trying to change the 
wrong spec?

In RM you are using a single header property to indicate two things: 
"we're doing back-channel here, and it's part of a logical connection, 
identified thus".

Why can't you separate the communication of these two semantics, by 
using two properties:

1) wsa:ReplyTo = anonymous URI
2) wsrm:MakeConnection = connection identity?

2) without 1) would be illegal.

In your example posted on the WS-RX list, you state that [reply 
endpoint] is not set because MakeConnection is a "one-way message". But 
it's a message that usually/frequently expects a reply (at a WS-A 
level). Unlike many other applications, a WS-RM MC sender will tolerate 
an empty response (no SOAP in the HTTP body), but I don't think that 
stops one viewing this as a utilization of the request-reply pattern 
implied by use of reply-to.

If you loosen the WSAW wording, then surely it becomes indeterminate. 
What does "required" imply on the wire, thereafter?

Alastair

Doug Davis wrote:
>
> To elaborate a little on Bob's note [1], in the WSA WSDL spec, when 
> talking about the various values for the Anonymous Element it lists:
>
> "optional": This value indicates that a response endpoint EPR in a 
> request message MAY contain an anonymous URI as an address.
> "required":This value indicates that all response endpoint EPRs in a 
> request message MUST always use anonymous URI as an address.
> If a response endpoint EPR does not contain the anonymous URI as an 
> address value, then a predefined InvalidAddressingHeader fault defined 
> in Web Services Addressing 1.0 - SOAP Binding [WS-Addressing SOAP 
> Binding] MUST be generated.
> "prohibited":This value indicates that any response EPRs in a request 
> message MUST NOT use anonymous URI as an address.
> If a response endpoint EPR contains the anonymous URI as an address 
> value, then a predefined InvalidAddressingHeader fault defined in Web 
> Services Addressing 1.0 - SOAP Binding [WS-Addressing SOAP Binding] 
> MUST be generated.
>
>
> The problem comes up when another spec defines their own version of 
> anonymous - like WS-RM does.  It defines an anon URI which acts almost 
> exactly like the WSA one in that it means "send it on the transport 
> specific back-channel".  However, if the wsaw:Anonymous element is set 
> to "required" then the above text would seem to imply that regardless 
> of whether or not the RM spec is supported by the endpoint, the client 
> can never send a wsa:ReplyTo with anything other than WSA's anonymous. 
>  So the above text precludes another spec from ever extending WSA to 
> define their own anon URI where from a WSA perspective its equivalent. 
>  If the text were loosened up a bit to not mention the WSA anon URI 
> specifically, but rather something more generic like: "... MUST always 
> use a URI implying the transport specific back-channel" then the use 
> of the wsaw:Anonymous element would not preclude other specs defining 
> their own anon URI and not violate the meaning of the wsaw:Anonymous.
>
> thanks
> -Doug
>
>
>
> [1] 
> http://lists.w3.org/Archives/Public/public-ws-addressing/2006Aug/0009.html 
Received on Friday, 4 August 2006 11:02:26 GMT

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