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RE: Optional Extensions

From: Glen Daniels <gdaniels@sonicsoftware.com>
Date: Tue, 27 Jan 2004 10:31:49 -0500
Message-ID: <80A43FC052CE3949A327527DCD5D6B270A320C@MAIL01.bedford.progress.com>
To: "Prasad Yendluri" <pyendluri@webmethods.com>, "Web Services Description" <www-ws-desc@w3.org>


I'm sorry, but I don't understand this whole "may ignore them" business.
What exactly is a processor going to do with an extension it doesn't
understand?  IMHO, it has to ignore them unless they are marked as
required, in which case it fails.  I think this is common sense, but it
wouldn't hurt to specify it either.

--Glen 

> -----Original Message-----
> From: www-ws-desc-request@w3.org 
> [mailto:www-ws-desc-request@w3.org] On Behalf Of Prasad Yendluri
> Sent: Monday, January 26, 2004 4:51 PM
> To: 'Web Services Description'
> Subject: Re: Optional Extensions
> 
> Hi,
> 
> We should follow the recommendation in section 6.1.1 in the 
> WSDL 2.0 core, for "mandatory" extensions. If wsdl:required 
> is false, the WSDL processor MAY ignore them. I mean it could 
> be a configurable option by the user of the processor, rather 
> than blindly ignoring them always. 
> 
> Prasad
> 
> 
> 6.1.1 Mandatory extensions
> 
> 
> Extension elements can be marked as mandatory by annotating 
> them with a wsdl:required attribute information item (see 
> 6.1.2 required attribute information item 
> <http://www.w3.org/TR/wsdl20/#required-aii> ) with a value of 
> "true". Mandatory extensions are those that MUST be processed 
> correctly by the WSDL processor. If a mandatory extension 
> element is processed, the WSDL processor MUST either agree to 
> fully abide by all the rules and semantics signaled by the 
> extension element's qualified name, or immediate cease 
> processing (fault). In particular, if the WSDL processor does 
> not recognize the qualified name of the extension element, it 
> MUST fault. If the WSDL processor recognizes the qualified 
> name, and determines that the extension in question is 
> incompatible with any other aspect of the document (including 
> other required extensions), it MUST fault.
> 
> -------- Original Message -------- 
> Subject: 	RE: Optional Extensions	 
> Date: 	Mon, 26 Jan 2004 13:11:51 -0800	 
> From: 	Philippe Le Hegaret <plh@w3.org> 
> <mailto:plh@w3.org> 	 
> To: 	David Orchard <dorchard@bea.com> 
> <mailto:dorchard@bea.com> 	 
> CC: 	'Web Services Description' <www-ws-desc@w3.org> 
> <mailto:www-ws-desc@w3.org> 	 
> 
> On Mon, 2004-01-26 at 15:47, David Orchard wrote:
> > Philippe, you are not understanding the relationship 
> between ignoring 
> > content and extensibility/versioning. If somebody makes a backwards 
> > compatible change to their wsdl by putting in an optional 
> > extension,they want to make sure that folks that don't know about 
> > their extension will not fall over and die. By underspecifying the 
> > behaviour of optional extensions in wsdl, they do not have an 
> > assurance that their change is backwards compatible.  By requiring 
> > that unknown extensions are ignored, there are assurances of 
> > compatible evolution.  This model worked very well for HTML 
> and HTTP headers, and is embodied in the soap:mustUnderstand 
> attribute.
> > There is extensive precedence for this.
> 
> Rereading your original, I now realize that you were talking 
> about the WSDL processors in the context of unknown optional 
> extensions, and not WSDL processors in the context of 
> optional extensions... I would propose that WSDL processors 
> MUST ignored unknown optional extensions if any, and MAY 
> process known optional extensions.
> 
> Philippe
> 
> -------- Original Message --------
> Subject: 	Optional Extensions	 
> Resent-Date: 	Mon, 26 Jan 2004 14:50:19 -0500 (EST)	 
> Resent-From: 	www-ws-desc@w3.org	 
> Date: 	Mon, 26 Jan 2004 11:51:29 -0800	 
> From: 	David Orchard <dorchard@bea.com> 
> <mailto:dorchard@bea.com> 	 
> To: 	<www-ws-desc@w3.org> <mailto:www-ws-desc@w3.org> 	 
> 
> If there is a WSDL extension which is not mandatory and not 
> recognized by the WSDL processor what is to be done with it? 
> Our suggestion is that it should be ignored, and that this 
> should be specified. Same thing applies to extension attributes.
> 
> Cheers,
> Dave 
> 
> 
Received on Tuesday, 27 January 2004 17:16:49 GMT

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