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RE: Issue 146 (default and anon actors, endpoints and ultimate re cipients - for danbri :-))

From: Doug Davis <dug@us.ibm.com>
Date: Tue, 6 Nov 2001 10:37:05 -0500
To: "Williams, Stuart" <skw@hplb.hpl.hp.com>
Cc: xml-dist-app@w3.org
Message-ID: <OF7B3C87C0.533BC37C-ON85256AFC.00545417@raleigh.ibm.com >
Agreed - "processing" is different than "just peeking".  :-)
I also agree that the wording you quoted does seem to prevent
the scenario I'd like to see us support - so using the current
spec how does someone say "here's a header, and I don't care
who *processes* it just as long as someone does" ?  I'm beginning
to think that we don't allow this (as of now).

In the 1.1 spec it says:
   The SOAP actor global attribute can be used to indicate
   the recipient of a header element.
Its the "can" part that interests me.  I read that to mean
that there may be other pieces of information that determine
who the recipient is.  So, in my head (scary place) I extended
that to  mean that any Node along the path may pick-off any header
and *process* it - as long as it adheres to the semantics defined
by the header.  And if this were true then my scenario would
be supported.  But we seem (based on ch2) to be headed away from
this.

-Dug


"Williams, Stuart" <skw@hplb.hpl.hp.com> on 11/06/2001 10:14:45 AM

To:   Doug Davis/Raleigh/IBM@IBMUS
cc:   xml-dist-app@w3.org
Subject:  RE: Issue 146 (default and anon actors, endpoints and ultimate re
      cipients - for danbri :-))



Hi Dug,

So now on the other tack of discussing the issue rather than framing it...

The 'tricky' word in what you describe is 'processed'. I think that we've
long agreed that there is little we can do to prevent any SOAP Node along
the message path peeking inside any part of the message (other than
encrypting it out of sight). I don't think that just looking constitues
processing. According to the Section 2 rules processing a SOAP Message at a
SOAP Node involves the removal (and possible replacement) of header blocks
targetted at that node [1]

Part 1 section 2.3 defines the targetting of SOAP headers and states
"...SOAP header blocks with no such attribute information item [actor] and
the SOAP body are implicitly targeted at the anonymous SOAP actor, implying
that they are to be *processed* by the *ultimate SOAP receiver*."

I guess you would argue... yes, but it doesn't say that blocks targetted at
default/anon can't be 'processed' elsewhere. It seems to me that all the
indications in the spec. are that default/anon is intended to denote the
ultimate recipient. I think this make it pretty implicit that there is only
one default/anon actor per message (excepting multicast cases!) - which
SOAP
Node along a message path takes on the default/anon actor role may be
emergent, but I think it is always the last node on the message path for
that message.

It may be that we want to separate the concepts of default actors,
anonymous
actors and ultimate recipients, but I think the terms have grown up as
synonyms and if they are distinct then we have not described the
differences.

Regards

Stuart
[1] http://www.w3.org/TR/soap12-part1/#procsoapmsgs
[2] http://www.w3.org/TR/soap12-part1/#N4002A2

> -----Original Message-----
> From: Doug Davis [mailto:dug@us.ibm.com]
> Sent: 06 November 2001 13:03
> To: xml-dist-app@w3.org
> Subject: RE: Issue 146
>
>
> Stuart,
>  Yep, sorry, I misunderstood your note.  Related to the issue at hand,
> I'm wondering how people view the following example:
>   <env>
>     <headers>
>       <h1 MU="1"/>
>       <h2 MU="1"/>
>     </headers>
>     <body.../>
>   </env>
>
> h1 and h2 don't have actor attributes.
> As you said in your note, people are using the terms default actor,
> anonymous actor and ultimate recipient interchangeably, so can h1
> and h2 be processed by anyone other than the ultimate recipient?
> I always thought so.  I interpreted it this way:
>  - any node along the message path may process untargeted headers
>    as long as they fully understand the semantics of the header
>  - the ultimate recipient, however, MUST assume the role of
>    default/anonymous actor.  Meaning that it MUST process h1 and h2
>    if they are still in the message.
> The main reason I see behind allowing other nodes to assume the role
> of the anon actor is that a client knows nothing about the message
> path - all it really knows is the one/next node it is supposed to
> send it's message to.  So, there will be times when it does not know
> what Nodes the message will pass through and as such can't control
> which Node along the message path will process which part - so by
> leaving the "actor" off (IMO) it is saying "I don't care which exact
> Node processes this header, just as long as it does get processed
> (hence the MU="1")."
> So, while I agree that the ultimate recipient is also the default/anon
> actor - I do not agree that a Node that acts as a default/anon
> actor is also the ultimate recipient.
> Am I alone in this interpretation?
> -Dug
>
Received on Tuesday, 6 November 2001 10:37:41 GMT

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