George Cristian Bina <[EMAIL PROTECTED]> wrote on 07/21/2005 02:30:12 PM:
> Hi,
>
> Here are a couple of thinks I noticed with the Xerces XInclude support
> wrt validation.
>
> Let's assume a simple scenario, one document main.xml that includes a
> document fragment.xml.
>
> If we run a validation without setting the schema feature and both
> main.xml and fragment.xml specify a DTD then
> * main.xml is validated against its DTD. let that be main.dtd
> * fragment.xml is validated against its DTD, let that be fragment.dtd
>From reading through your e-mail, I guess what you may be wondering here
is why DTD validation isn't being performed on the result infoset. If
that's the case consider the following document (if not you can ignore the
rest of this section):
<?xml version="1.0"?>
<!DOCTYPE xi:include [
<!ELEMENT xi:include (xi:fallback?)>
<!ATTLIST xi:include
xmlns:xi CDATA #FIXED "http://www.w3.org/2001/XInclude
"
href CDATA #IMPLIED
parse (xml|text) "xml"
xpointer CDATA #IMPLIED
encoding CDATA #IMPLIED
accept CDATA #IMPLIED
accept-language CDATA #IMPLIED>
<!ELEMENT xi:fallback ANY>
<!ATTLIST xi:fallback
xmlns:xi CDATA #FIXED "http://www.w3.org/2001/XInclude";>
]>
<xi:include href="fragment.xml"/>
If the DTD validator is placed after the XInclude processor, then the
xmlns:xi attribute will not yet have been defaulted into the document,
meaning the prefix xi will not have been bound to "
http://www.w3.org/2001/XInclude"; when the XInclude processor sees the
xi:include element. The infoset being passed to the XInclude processor
here isn't complete. Though one can imagine how to do DTD validation on
the result of an XInclude, you really can't decouple DTD related
processing from the parsing process.
> If we run a validation and specify the schema feature and both main.xml
> and fragment.xml specify an XML schema then
> * the content of main.xml with xi:include replaced with the content of
> fragment.xml is validated against the XML Schema specified in main.xml,
> let that be main.xsd
> * fragment.xml is *not* validated against its schema, let that be
> fragment.xml
What if you don't have a schema for fragment.xml or don't want to validate
fragment.xml? What if fragment.xml contains xi:include elements, do you
want the parser to validate before or after inclusion or both? What if you
have a fragment2.xml which main.xml includes and you don't want to
validate it but you still want to validate fragment.xml? The schema
feature is a boolean so it can't handle these preferences. We did think
about how to go about supporting these combinations [1] but we don't have
a solution yet. An XML pipelining language might help.
In a JAXP 1.3 context if a javax.xml.validation.Schema is set on the
parser, validation occurs after any other processing (including XInclude)
so the schema validation behaviour you get when the schema feature is
turned on is consistent with JAXP.
> If we set the schema feature to true and both documents specify a DTD
then:
>
> * main.xml is validated against main.dtd
> * fragment.xml is *not* validated
The current behaviour is the result of the fix for Jira bug #843 [2]. To
be consistent with what occurs on the main pipeline, I suppose validation
should occur if the document being processed on the child pipeline has a
DTD and if it doesn't then no errors should be reported for it not having
a DTD grammar. Fixing this behaviour in 2.7.1 is probably doable.
> To summarize, there is a totally different behavior of the validate
> action when XInclude is enabled, for XML Schema the validation is done
> on the master file with XInclude instructions resolved while for DTD the
> validation is performed on each document without expanding the XInclude
> instructions.
>
> More problematic however seems the case when the schema feature is set
> to true and the documents specify DTDs. In this case the main document
> with Xinclude instructions not expanded is validated against the DTD but
> in the XInclude handler the validation is turned off, thus the included
> documents are not validated at all. In this case the XInclude handler I
> think should at least behave in a similar way as the main pipeline, that
> is it should validate the included document against its DTD.
>
> Any insights on these will be appreciated.
> Are there any chances for fixing at least this last part in 2.7.1?
> Let me know if I should file a bug on Jira.
>
> Best Regards,
> George
> ---------------------------------------------------------------------
> George Cristian Bina
> <oXygen/> XML Editor, Schema Editor and XSLT Editor/Debugger
> http://www.oxygenxml.com
>
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>
Thanks.
[1] http://marc.theaimsgroup.com/?l=xerces-j-user&m=112166040310811&w=2
[2] http://issues.apache.org/jira/browse/XERCESJ-843
Michael Glavassevich
XML Parser Development
IBM Toronto Lab
E-mail: [EMAIL PROTECTED]
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