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RE: Issue 140 bogus?

From: Williams, Stuart <skw@hplb.hpl.hp.com>
Date: Tue, 2 Oct 2001 19:08:08 +0100
Message-ID: <5E13A1874524D411A876006008CD059F19266D@0-mail-1.hpl.hp.com>
To: "'Jacek Kopecky'" <jacek@idoox.com>
Cc: David Fallside <fallside@us.ibm.com>, xml-dist-app@w3.org
Hi Jacek,

I think that the matter is a little different. I guess that we could take
two different tacks, here. 

The tack you seem to be following is that the default actor is just another
actor, and the issue of determining whether you are a given actor is no
different for the default actor than it is for an other actor. If we persue
that tack, then I think I would continue to have an issue in that our
current draft then offers little if any discussion of possible basis for a
SOAP node to determine that it performs the role of any given actor
(particularly if the roles its willing to play wrt to a given message are
dependent on the content of the message - which is partially hinted at).

The other tack which I was persuing was the the anonymous actor, the "actor
who cannot be named" (think Harry Potter :-), is infact different. All SOAP
messages have one. On the surface at least there is nothing in the message
(other than the message itself) that gives a basis for a Node to determine
whether it acts in the default role for a given message. For non-default
actors the actor notion is at least evocative of the simple idea the the
message should visit (in some unspecified order) a set of actors directly
referenced by the value of the associated actor attribute. For this simple
case, resolution of the actor name to a request-URI would at least apprear
obvious for http based actor URIs and using the http binding (no-doubt there
are some subtlties). Resolving
http://www.w3.org/2001/09/soap-envelope/actor/default this way isn't very
helpful!

Issue 140 is that there is little/no discussion of these matters in the
draft spec, narrowly cast as a problem in resolving whether a SOAP Node is
the default actor with respect to a given message. I think your response
would cause me to want to broaden the issue rather than regard it as bogus!

On the constructive side, I've been thinking about this a bit as well. I
think this takes us down a path of questioning the relationship between the
request-URI (an HTTP binding concept)/transport endpoints(maybe more
generic), a SOAP node, the actor roles supported by a SOAP Node (possibly
wrt to a given message), and our notions of what sort of things we might be
naming/addressing as SOAP endpoints.

I think a pragmatic way out might be to acknowledge that the choice of
transport endpoint for a given message (or message exchange) may be the
thing that determines the set of actor roles engaged at that physical node
to process an inbound message. One could concieve of the following
functions:

1)	boolean IAmThatActor(ActorUri);

2)	boolean IAmThatActor(ActorUri,Message);

3)	boolean IAmThatActor(ActorUri,InboundTransportEndpoint);

4)	boolean IAmThatActor(ActorUri,Message,InboundTransportEndpoint);


1) is akin to the simple scheme mentioned above, and is not very useful when
it comes to the default/anon actor. 2) is a little more useful, and would
admit behaviour like SOAP-RP or ebXML where header fields (targetted at
../next) will influence the determination. 3) basically captures a notion of
the a collection of actors being configured behind a given transport
endpoint (and useful intermediaries would likely not list default/anon
amongst the actors at the endpoints they use :-)). 4) is a hybrid, that
seems to have all the bells and whistles (apart from time dependent
variation, the phase of the moon or whatever).

Sorry, this is so long... its the first time I've written this down. I think
basically I am optimistic that we could resolve Issue 140. I don't think its
a non-Issue. I don't think that the spec currently gives much guidance about
the self determination by a SOAP Node of whether it acts in a particular
role with respect to a given message. That said, I don't think that requires
lots of discussion.

Regards

Stuart



> -----Original Message-----
> From: Jacek Kopecky [mailto:jacek@idoox.com]
> Sent: 02 October 2001 17:45
> To: Stuart Williams
> Cc: David Fallside; xml-dist-app@w3.org
> Subject: Issue 140 bogus?
> 
> 
>  Stuart,
>  I believe your issue with the section 2.3 of the first part of
> our draft spec is not an issue.
>  The actor URI, if present, is not specified to be anything in
> particular, it's just a URI that the targetted actor somehow
> knows is point at him. If instead of targetting the default actor
> with a missing actor URI we targetted it with the URI
> "http://www.w3.org/2001/09/soap-envelope/actor/default", the
> situation would be completely equivalent.
>  And yes, the set of Actor URIs a node acts as is an *outside*
> information to the envelope.
>  Best regards,
> 
>                             Jacek Kopecky
> 
>                             Idoox
>                             http://www.idoox.com/
> 
Received on Tuesday, 2 October 2001 14:08:53 GMT

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