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Re: RPCTF: Should RPC be core or an extension ?

From: Francis Norton <francis@redrice.com>
Date: Wed, 25 Jul 2001 16:41:36 +0100
Message-ID: <3B5EE8B0.B4B2B780@redrice.com>
To: John Ibbotson <john_ibbotson@uk.ibm.com>
CC: xml-dist-app@w3.org
<de-lurk>

+1 for this - in addition to the reasons outlined below, I would add
that for e-commerce application development, document exchange is more
basic than RPC because:

[a]	we (at least in our company) already have schemas as a deliverable
from our business analysis
[b]	RPC requires a lower-level assumption of transport protocol than XML
Schema does - eg document-based messaging can be mapped by WSDL to SOAP
or simple HTTP posts, but RPC would be specific to SOAP
[b]	on greenfield projects we expect our schemas to "evolve", and my
reading of RPC is that it would tighten the coupling between the
messages and the transport code, and thus increase the costs of schema
alterations.

</de-lurk>

John Ibbotson wrote:
> 
> Should RPC be part of the core SOAP specification or an architected
> extension ?
> 
> I believe the SOAP 1.1 specification confused matters by including sections
> on RPC and encoding. Readers of the specification came to the incorrect
> conclusion that SOAP was inextricably linked to RPC. As Henrik pointed out
> inthe early days of the WG, SOAP is really only a single way message with
> RPC being a convention for linking two single way messages into a
> request/response pair together with an encoding mechanism. By removing  RPC
> from the core specification and placing it into a separate extension, we
> have the opportunity to correct the confusion that I believe originates
> from SOAP 1.1.
> 
> There is a second reason for removing RPC from the core specification.
> There is a large body of users (the EDI community via ebXML) for whom RPC
> is not the preferred invocation mechanism. They operate with a document
> exchange model which may include boxcarring of business documents in a
> single message each of which is of equal processing importance. If the WG
> perpetuates the perceived importance of RPC by including it in the core
> specification rather than viewing it as an extension, then acceptance of
> SOAP in some communities may be diminished.
> 
> Comments please,
> John
> 
> XML Technology and Messaging,
> IBM UK Ltd, Hursley Park,
> Winchester, SO21 2JN
> 
> Tel: (work) +44 (0)1962 815188        (home) +44 (0)1722 781271
> Fax: +44 (0)1962 816898
> Notes Id: John Ibbotson/UK/IBM
> email: john_ibbotson@uk.ibm.com
Received on Wednesday, 25 July 2001 11:42:42 GMT

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