SOAP and Processing Instructions

Simon Fell asked about SOAP and Processing Instructions here:

 * http://lists.w3.org/Archives/Public/xmlp-comments/2002Jul/0047.html

He presented a use-case that a few of us came up with while working with
a real-world service.

Noah Mendelsohn replies:

> Just my opinion, but the Get binding is not to make SOAP easier to use 
> with browsers and other user agents that might benefit from the PI.  

Nevertheless, if compatibliity can be easily achieved, I think that we
should do so.

> ... The 
> binding is specifically there to cause SOAP processing of the response. 
> SOAP processing is entirely driven by the element structure of the SOAP 
> envelope, and PI's really don't fit with that.  If a PI appears 
> immediately before a header entry, should it be taken to modify that 
> entry? 

The SOAP specification already has the answer to this question:

"A SOAP receiver MUST ignore processing instruction information items in
SOAP messages that it receives."

> Should it be removed from the message along with that entry after 
> processing?  etc.  

I personally do not think it matters whether they are preserved across
hops or not so you could just answer "not". The same goes for comments
(which should also be allowed).

Overall, I think that the restrictions that SOAP makes on XML should be
minimized in subsequent versions. Ideally, SOAP would be a clean layer
on top of either XML or a separately defined subset of XML. We will end
up in a very bad place if XML vocabularies start to routinely define
their own subsets of XML syntax. If XML needs a subset then we should
define it "through the front door". But that is spilt milk for SOAP 1.2.
-- 
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Received on Tuesday, 30 July 2002 15:57:47 UTC