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.

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.

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 Wednesday, 10 November 2004 18:52:00 UTC