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Re: Handling the XML Prolog inside SOAP

From: <noah_mendelsohn@us.ibm.com>
Date: Tue, 13 May 2003 22:55:26 -0400
To: "Burdett, David" <david.burdett@commerceone.com>
Cc: "XML Dist-App (E-mail)" <xml-dist-app@w3.org>
Message-ID: <OF27AC707A.0A6B665D-ON85256D26.000F3121@lotus.com>

Short answer:  no, you're not missing anything.  A fundamental decision in 
SOAP was to model messages primarily as XML.  This gives us lots of 
synergy with XML tools, schema languages, etc., but it means we also pick 
up the limitations of XML.  In general, it is not possible 
(unfortunately!) to nest multiple XML documents in a single outer 
document. That's an XML limitation, not particular to SOAP.   Any DTD 
would have to be at the outside, and all its declarations (for IDs, 
entities, and the like) would apply to the entire document.  IDs could 
conflict or IDREFS could be unintentionally resolved, etc.   Depending on 
how you do it, there can be issues with default namespaces, etc.  I think 
this is probably one of the major design flaws in XML, but there it is. 
Nested XML documents can be carried in SOAP as attachments using the 
attachment technology of your choice, or as base64binary or hexBinary 
encodings. 

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Noah Mendelsohn                              Voice: 1-617-693-4036
IBM Corporation                                Fax: 1-617-693-8676
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"Burdett, David" <david.burdett@commerceone.com>
Sent by: xml-dist-app-request@w3.org
05/13/2003 12:49 PM

 
        To:     "XML Dist-App (E-mail)" <xml-dist-app@w3.org>
        cc:     (bcc: Noah Mendelsohn/Cambridge/IBM)
        Subject:        Handling the XML Prolog inside SOAP


I'm reposting this question as I did not get any response earlier.
 
The SOAP PR spec [1] states a SOAP message must not contain information 
that often goes in the XML Prolog such as: document type declarations, 
processing instructions or comments before the main document element.
 
A question. What should you do if the XML that you want to transport was 
originally a complete XML document (perhaps digitally signed) that 
contains this type of information and you want this information to be 
preserved when the document reaces the ultimate destination so that it can 
be used?
 
My reading of the current SOAP spec suggests that this is not possible 
unless you Base64 encode it ... or am I missing something.
 
David
PS I realise this may have been already discussed but I missed it.
 
[1] http://www.w3.org/TR/soap12-part1/#soapenv 
Received on Tuesday, 13 May 2003 23:04:59 GMT

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