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RE: i028: Implications of the presence of ReplyTo

From: Martin Gudgin <mgudgin@microsoft.com>
Date: Thu, 11 Nov 2004 04:26:01 -0800
Message-ID: <DD35CC66F54D8248B6E04232892B633803EDB6CE@RED-MSG-43.redmond.corp.microsoft.com>
To: "Marc Hadley" <Marc.Hadley@Sun.COM>, <public-ws-addressing@w3.org>

 

> -----Original Message-----
> From: public-ws-addressing-request@w3.org 
> [mailto:public-ws-addressing-request@w3.org] On Behalf Of Marc Hadley
> Sent: 10 November 2004 18:52
> To: public-ws-addressing@w3.org
> Subject: i028: Implications of the presence of ReplyTo
> 
> 
> Issue 28[1] concerns the implications of the presence of 
> ReplyTo in a  
> message. Does the presence of a wsa:ReplyTo imply that a reply is  
> required, does absence of ReplyTo indicate a one-way message ?
> 
> <wsa:ReplyTo> is optional and the specification states that:
> 
> (i) It "MUST be present if a reply is expected",
> (ii) But "If the [reply endpoint] is absent, the contents of the  
> [source endpoint] may be used to formulate a message to the source."  
> [reply endpoint] serializes as wsa:ReplyTo, [source endpoint]  
> serializes as wsa:From.
> 
> I.e. <wsa:ReplyTo> must be present, but if not use <wsa:From> 
> instead -  
> the two statements seem to be contradictory.

I don't think they are. If you expect a reply ( e.g. you're sending the
initial message a WSDL 1.1 request-response ) then the message you send
MUST have a [reply endpoint] property. I think the second clause about
[source endpoint] is just informational, it doesn't have any bearing on
the previous text. May be it should be under [source endpoint]?

> 
> If we accept (i) then a typical use of a request response MEP 
> using the  
> SOAP/HTTP binding would require the presence of the following header  
> block:
> 
> <wsa:ReplyTo>
>     
> <wsa:Address>http://schemas.xmlsoap.org/ws/2004/08/addressing/role/ 
> anonymous</wsa:Address>
> </wsa:ReplyTo>
> 
> This is a lot of bytes that provide no real information. My 
> preference  
> would be that omission of a ReplyTo is semantically 
> equivalent to its  
> presence as shown above but that would mean that its presence 
> cannot be  
> used to determine whether a reply is expected or not.

I think providing a 'default' value in the case is a mistake. I saw one
of the benefits of WS-Addressing was that the headers that appeared in a
message DID NOT vary depending on how the message was actually
transmitted.

Gudge

> 
> Marc.
> 
> [1] http://www.w3.org/2002/ws/addr/wd-issues/#i028
> ---
> Marc Hadley <marc.hadley at sun.com>
> Web Technologies and Standards, Sun Microsystems.
> 
> 
> 
Received on Thursday, 11 November 2004 12:26:36 GMT

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