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Re: PROPOSAL: Drop interface/operation/(input|output)/@headers

From: Jean-Jacques Moreau <jean-jacques.moreau@crf.canon.fr>
Date: Tue, 21 Oct 2003 18:21:40 +0200
Message-ID: <3F955D14.6030504@crf.canon.fr>
To: Sanjiva Weerawarana <sanjiva@watson.ibm.com>
Cc: www-ws-desc@w3.org, Jonathan Marsh <jmarsh@microsoft.com>, FABLET Youenn <youenn.fablet@crf.canon.fr>, Herve Ruellan <herve.ruellan@crf.canon.fr>

Wow, what a shock!

The immediate SOAP proponent in me says no, we can't really just drop 
headers! I haven't ever considered SOAP header blocks as just 
"middleware"; I know some do.

Of course, the feature argument sounds compelling... although it opens 
the door to features being dropped in a (hypothetical) second step, 
which I would oppose.

Obviously, I need to think more about this. I am generally in favour of 
simplification, but I also like flexibility.

Jonathan, since I will be away on Thursday, and since Youenn will have 
just come back from paternity leave, can we please differ discussion of 
Sanjiva's proposal until next week?

Thank you,


Sanjiva Weerawarana wrote:

> During the <message> elimination process, I proposed that it be
> eliminated by introducing a single element that may go as the 
> body of the message and zero or more "header" elements. The motivation
> was that it was possible in WSDL 1.1 to have such header and body
> parts and we didn't want to lose that functionality.
> The main use of the "header" parts are to enable one to use WSDL
> to describe middleware protocol type "applications" of WSDL. That
> is, one can imagine protocols requiring certain headers to be 
> present etc..
> However, to fully describe such protocols the header stuff has to
> be much much richer. If you look at the original context proposal
> I made back in January this year, you'll see some of that richness,
> but even that is not enough.
> At the same time, complicating WSDL to the extent needed to make
> it possible to fully describe a handful of middleware protocols
> when compared to the millions of "regular" applications doesn't
> seem like the right tradeoff. 
> Thus, we now propose we drop the "headers" concept from input and
> output messages. Messages will simply be a single XML element. 
> I also propose a simple syntactic change to exploit this new 
> simplified structure of messages. Rather than the current form:
>     <input messageReference="xs:NCName" 
>            body="xs:QName"? headers="list of xs:QName"?/>
> I suggest we use:
>     <input messageReference="xs:NCName" 
>            message="xs:QName"/>
> And similarly for <output>. The same syntactic approach can be
> used to make <fault>s consistent with this approach. Rather the
> current form:
>     <infault messageRefernce="xs:NCName" details="xs:QName"/>
> I suggest we use:
>     <infault messageReference="xs:NCName" message="xs:QName"/>
> And similarly for <outfault>.
> Thus, this email proposes the following changes to status quo:
>     - drop interface/operation/(input|output)/@headers
>     - rename interface/operation/(input|output)/@body to
>       interface/operation/(input|output)/@message
>     - rename interface/operation/(infault|outfault)/@details to
>       interface/operation/(infault|outfault)/@message
> Sanjiva.
Received on Tuesday, 21 October 2003 12:25:20 UTC

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