What is a SOAP Message

During today's AFTF telcon we got into a discussion as to exactly what a
SOAP Message is.  Gudge pointed out that in several places in part 1 it
says or strongly implies that a SOAP Message >is< an XML Envelope Infoset.
I had always assumed we were clear that the "term message" refers not just
to the envelope, but to a set of information which includes at minimum the
envelope, but often other information as well (e.g., the destination
address, WebMethod, and Action tend to be sent out of band in SOAP http).
So, here is a quick list of some of the references to the term Message as
they relate to this potential misunderstanding:

[1]:  "SOAP message
The basic unit of communication between SOAP nodes.

SOAP envelope
The outermost element information item of a SOAP message."

(Vaguely supportive of my position, but could be read either way)

[2] "A SOAP message is specified as an XML infoset that consists of a
document information item with exactly one member in its [children]
property, which MUST be the SOAP Envelope element information item (see 5.1
SOAP Envelope)."

(Seems to support Gudge's view)

[3] (note this is from part 2):  "In general, a SOAP message is the
information that one SOAP node wishes to exchange with another SOAP node
according to a particular set of features, including a MEP. In addition,
there may be information essential to exchanging a message that is not part
of the message itself. Such information is sometimes called message
meta-data. In the model, the message, any message meta-data, and the
various information items that enable features are represented as
abstractions called properties."

(Supports my view, I think.  This is what I've been remembering.)

I think it's useful and appropriate to separate the term "message" from
"envelope".   I think the destination and web method are surely part of the
message.  I understand that Gudge is interested in exploring a design point
in which all information in the message is reflected (or reflectable after
some transform) in a message infoset.  That's an interesting design point
to consider, but it's clearly not the case today.  I think we should
consider clarifying our terminology.  Thank you.

Noah

[1] http://www.w3.org/TR/2002/CR-soap12-part1-20021219/#encapsulation
[2] http://www.w3.org/TR/2002/CR-soap12-part1-20021219/#soapenv

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Noah Mendelsohn                              Voice: 1-617-693-4036
IBM Corporation                                Fax: 1-617-693-8676
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Received on Monday, 3 February 2003 12:52:32 UTC