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Re: Revised proposed text for intermediary

From: Hugo Haas <hugo@w3.org>
Date: Thu, 17 Jul 2003 10:21:50 +0200
To: michael.mahan@nokia.com
Cc: www-ws-arch@w3.org
Message-ID: <20030717082150.GC16430@w3.org>
Hi Mike.

* michael.mahan@nokia.com <michael.mahan@nokia.com> [2003-07-16 16:52-0400]
> >      2.3.1.2 Intermediary
> >
> >        2.3.1.2.1 Definition
> >
> >  An intermediary is an agent that is both a message recipient and a
> >  message sender. An intermediary may process some aspect of the
> >  message, and acts to forward the message to the next message
> >  recipient towards an ultimate message receiver along the message
> >  path.
> >
> 
> Are we purposefully relaxing XMLP's definition [1] of SOAP intermediary
> for
> purposes of the architecture?
> 
> "A SOAP intermediary is both a SOAP receiver and a SOAP sender and is 
> targetable from within a SOAP message. It processes the SOAP header
> blocks 
> targeted at it and acts to forward a SOAP message towards an ultimate
> SOAP 
> receiver."
> 
> I read that a SOAP intermediary, by definition,
> 1) is explicitly targeted via a SOAP message 
> 2) must processes SOAP header blocks

I don't think that the definition says that the SOAP intermediary has
to be explicitely targeted, only that they can be.

> If we are not relaxing the definition, then I would s/may/must/

I used "may process" thinking about the case of an active intermediary
which would end up inspecting the message and making the decision of
not doing anything to it and forwarding it as received. However,
"processes" works as well in the end: after all, parsing and making
the decision of not doing anything is processing.

> >        2.3.1.2.2 Relationships to other elements
> >
> >   an intermediary is
> >
> >           an agent
> >
> >   an intermediary may have partial access
> >
> >           to messages it processes.
> 
> If we are not trying to relax the SOAP definition, then by 
> same reasoning, I would say:
> 
> An intermediary must process the message according to its application
> role. T
> he post-processed message is forwarded. 

Should we be talking about roles here? Is that an implementation
detail of intermediaries?

If the answer is no, we can add the following relationship:

  an intermediary acts in

     a role

A new concept "role" would need to be added.

Regarding the forwarding part, we can add the following:

  an intermediary forwards

    the message along the message path

> >        2.3.1.2.3 Explanation
> >
> >   Intermediaries process messages and then forward them along the
> >   message path. An intermediary is not the ultimate message recipient
> >   of a message.
> >
> >   A message may be intended for an intermediary, or may be
> >   transparently processed by one.
> 
> This is confusing if we are consistent with SOAP defintion. If a SOAP
> message
> arrives at a SOAP intermediary to be processed, then it must have been
> targeted.
> 
> Not sure what transparent means. It seems like you mean that an
> intermediary can 
> process a message even if the message was not intended to arrive there.
> This makes
> no sense to me. SOAP messages are hop to hop so if it arrives at hop_2
> then hop_1 must
> have intended for that to happen. Or maybe I am missing something here.

Does the revised text ([2] with the modification [3]) address your
concerns?

Regards,

Hugo

  2. http://lists.w3.org/Archives/Public/www-ws-arch/2003Jul/0107.html
  3. http://lists.w3.org/Archives/Public/www-ws-arch/2003Jul/0110.html
-- 
Hugo Haas - W3C
mailto:hugo@w3.org - http://www.w3.org/People/Hugo/

Received on Thursday, 17 July 2003 04:21:51 GMT

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