Re: Proposed resolution for Issue 50 (Misallignment of faut to and reply to )

Having thought it over, I still prefer this formulation:

    * Bindings MAY define a default destination for faults and/or replies.
    * A missing ReplyTo or FaultTo is interpreted according to the binding.
          o E.g., SOAP/HTTP defaults both to the backchannel.
          o something over email might default one or both to the From
            address.
          o other bindings may require both always to be present --
            results are undefined otherwise
    * You could also use the anonymous endpoint designation to
      explicitly to invoke this default behavior, if you like that sort
      of thing.  Sort of a "this page intentionally left blank".  But if
      there is no semantic difference between missing and anonymous, I'm
      not sure what anonymous is bringing to the party.

We /could/ also make the over-arching rule that a missing FaultTo 
defaults to the ReplyTo (which may in turn default as above), but I'm 
not sure this is a good idea.  For example, what does it mean for robust 
out-only, where there may be a fault but will not be a reply?  It would 
also interfere with bindings that have naturally different destinations 
for faults and replies.  I can't name such a binding, but I'm not 
willing to say it can't exist.

Tom Rutt wrote:

>
> As currently specified, an EPR is allowed to have th value “anonymous” 
> for the wsa:ReplyTo element. In this case, the reply goes back to the 
> sender over the HTTP response, just as if not using addressing.
>
> I would like to have an optimization (just as we did for wsa:To) that 
> absence of wsa:ReplyTo is semantically equivalent to using the 
> “anonymous” value.
>
> Also: we almost agreed to have missing FaultTo implying use of ReplyTo 
> when a fault is to be sent.
>
> Proposal to resolve Issue 50:
>
> First cut at text to add to the spec in definition of wsa:ReplyTo:
> “
> In the case of a message for which a reply is expected, the implied 
> semantics of wsa:ReplyTo not present are equivalent to it being 
> present with the anonymous URI.
> “
>
> In the definition for wsa:FaultTo, add the statement:
> “
> If wsa:FaultTo is absent, a Fault may be sent to the value (explicit 
> or through the implicit indication of “anonymous”) for wsa:ReplyTo..
>
>
>