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RE: i028: Implications of the presence of ReplyTo

From: Martin Gudgin <mgudgin@microsoft.com>
Date: Fri, 12 Nov 2004 09:11:26 -0800
Message-ID: <DD35CC66F54D8248B6E04232892B633803F294F7@RED-MSG-43.redmond.corp.microsoft.com>
To: <tom@coastin.com>, "Marc Hadley" <Marc.Hadley@sun.com>
Cc: <public-ws-addressing@w3.org>

 

> -----Original Message-----
> From: Tom Rutt [mailto:tom@coastin.com] 
> Sent: 12 November 2004 17:02
> To: Marc Hadley
> Cc: Martin Gudgin; public-ws-addressing@w3.org
> Subject: Re: i028: Implications of the presence of ReplyTo
> 
> I think the acknowledged PO operation, followed by a later 
> Invoice, is 
> an application specific protocol, where we
> are working on an "infrastructure" protocol.
> 
> What I mean by this is that, the "callback" address for the 
> supplier to 
> deliver the later invoice to (which can occur months later for
> a complicated Purchase) is an application level data Item, 
> and belongs 
> in the purchase order itself (in the soap body), not in a soap header.
> 
> So I now am thinking that the "wsa:replyTo" should only be 
> scoped to a 
> single MEP (i.e. the request response for the orginal PO request, with
> the response being the ack with the Vendor's POID.   The wsa:replyTo 
> should not be used by the application for the callback to send
> the future invoice to.

Why should the scope of wsa:* headers be limited to a single MEP? I
don't see any reason to bring in such a restriction, it will make
WS-Addressing much less useful.

> 
> Also, if there is no need for transport independence, the 
> message should 
> not have to send wsa:reply to when a wsdl request/response is bound
> to a request/response transport (e.g., soap http/post binding).   

How does the crafter of a message determine whether there is a need for
transport independence or not? I might be adding WS-Addressing headers
to a message at a layer that is unaware of the binding in use. And the
layer processing the WS-Addressing headers on the receiver side might
not know what binding the message came in on. 

> I 
> would say wsa:replyTo is only required to be send when the request / 
> response
> is bound to a one way underlying transport.

I really believe this would be a mistake. I really want a world where
the set of headers is NOT dependant on *how* the message is transmitted
( or how some future message will be transmitted ).

Gudge

> 
> Tom Rutt
> 
> Marc Hadley wrote:
> 
> >
> > On Nov 12, 2004, at 6:08 AM, Martin Gudgin wrote:
> >
> >>>
> >>> On Nov 11, 2004, at 3:01 PM, Martin Gudgin wrote:
> >>>
> >>>>> So it sounds like you'd be in favor of saying that presence
> >>>>> of ReplyTo
> >>>>> implies a request is expected and that absence 
> indicates a one-way
> >>>>> message ?
> >>>>
> >>>>
> >>>> Nope. I think that if you expect a reply, you MUST specify [reply
> >>>> endpoint]. So in request-response style MEPs [reply 
> endpoint] would
> >>>> always be specified in the request message. However, I
> >>>
> >>> don't think that
> >>>
> >>>> specifying [reply endpoint] necessarily means you expect 
> a reply (in
> >>>> request/response stylee). Does that make sense. I'm saying
> >>>>
> >>>>     if a then b
> >>>>
> >>>> but I'm NOT saying
> >>>>
> >>>>     if b then a
> >>>>
> >>> I understand what you mean but I'm not sure it makes 
> sense ;-). If we
> >>> could say that presence of ReplyTo indicates that a reply 
> is expected
> >>> then that would seem like a useful semantic. What's the 
> purpose of a
> >>> ReplyTo in a message that isn't expected to generate a reply ?
> >>
> >>
> >> OK, it depends on what you mean when you say 'generate a 
> reply'. Do you
> >> mean
> >>
> >> a) 'generate a reply as part of the same WSDL MEP'
> >>
> > Yes.
> >
> >> b) 'generate a reply, not necessarily part of the same WSDL MEP'
> >>
> >> I have certain protocols that do specify a [reply 
> endpoint], do expect
> >> (hope?) that a reply to be sent at some point, but NOT as 
> part of the
> >> same WSDL operation as the initial message.
> >>
> > That's the kind of scenario I was getting it when I raised 
> issue i015 
> > about redirection. E.g. if a responder in a request 
> response MEP sends 
> > back a ReplyTo header, do we expect that to apply to subsequent 
> > interactions between the requester and responder. I.e. what is the 
> > scope of the effect of a ReplyTo, is it scoped to an instance of a 
> > particular MEP or something wider ? Till now I'd been assuming the 
> > former, are you suggesting it should be the latter ?
> >
> > Cheers,
> > Marc.
> >
> > ---
> > Marc Hadley <marc.hadley at sun.com>
> > Web Technologies and Standards, Sun Microsystems.
> >
> >
> 
> -- 
> ----------------------------------------------------
> Tom Rutt	email: tom@coastin.com; trutt@us.fujitsu.com
> Tel: +1 732 801 5744          Fax: +1 732 774 5133
> 
> 
> 
Received on Friday, 12 November 2004 17:12:03 GMT

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