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Cross-referencing accross multiple documents and sorting: Bug in MSXML4 SP1 when using current() in an xsl:sort/@select value
- From: David Chryst <dchryst at yahoo dot com>
- To: XSL-List at lists dot mulberrytech dot com
- Date: Mon, 29 Apr 2002 11:20:46 -0700 (PDT)
- Subject: [xsl] Cross-referencing accross multiple documents and sorting: Bug in MSXML4 SP1 when using current() in an xsl:sort/@select value
- Reply-to: xsl-list at lists dot mulberrytech dot com
Subject: Cross-referencing accross multiple documents
and sorting: Bug in MSXML4 SP1 when using current() in
an xsl:sort/@select value
Date: 29 Apr, 2002
FYI:
There is a bug in MSXML4 when using current() in an
xsl:sort/@select value. In that context, current()
resolves to the wrong node. Microsoft will release a
fix with MSXML 4.0 Serivce Pack 2. No date has been
set for that release.
Normally, you can use a key() function when doing a
cross-reference sort. However, sometimes you have to
cross-reference data in 2 separate XML documents and
do a sort. For example, suppose you get 1 XML
document from some SOAP service that includes month
names in the data. You could define the order of
months in some static XML document and cross-refence
that month-order XML document in your XSLT script
using the document() function. In this case, you
can't use a key element with the data in the static
XML file!
Using the current() function: rather than performing 2
separate transforms, I was able to use a single
transform, but I had to use the current() function
call in the xsl:sort/@select value. This worked great
in production for several XSLT scripts when I used
MSXML3, but my sort returned data in document order
once I upgraded to MSXML4.
Here's an example. This example is simpler than what
I'm using in production, but it demonstrates the bug:
Here's my dynamically-generated XML: Execute the XSLT
against this document.
<large-collection>
<collection name = "groupA">
<ref refid="1"/>
<ref refid="3"/>
</collection>
<collection name = "groupB">
<ref refid="3"/>
<ref refid="4"/>
</collection>
<collection name = "groupC">
<ref refid="1"/>
<ref refid="2"/>
<ref refid="3"/>
<ref refid="4"/>
<ref refid="5"/>
<ref refid="6"/>
<ref refid="7"/>
<ref refid="8"/>
<ref refid="9"/>
</collection>
</large-collection>
Here's my static XML document that I am
cross-referencing. I saved it to c:\temp\parts.xml
Do not execute the XSLT against this XML document.
This file is cross_refenced in the xsl. If you save
this XML as something other than c:\temp\parts.xml,
you must alter the XSLT script.
<parts>
<part id="1" type="type-a" name="name-a"/>
<part id="2" type="type-a" name="name-b"/>
<part id="3" type="type-b" name="name-c"/>
<part id="4" type="type-d" name="name-d"/>
<part id="5" type="type-b" name="name-e"/>
<part id="6" type="type-c" name="name-f"/>
<part id="7" type="type-d" name="name-g"/>
<part id="8" type="type-b" name="name-h"/>
<part id="9" type="type-c" name="name-i"/>
</parts>
Here's my XSLT that takes the parts referenced in
groupC of the dynamically-generated XML, and sorts all
the parts in that group by type, then by name:
<?xml version="1.0"?>
<xsl:stylesheet
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
version="1.0">
<xsl:output method="html" />
<xsl:variable
name="MyGroup">groupC</xsl:variable><!--normally this
would be a param-->
<xsl:variable name="MyParts"
select="document('c:\temp\parts.xml')/parts"/>
<xsl:template match="/large-collection">
<xsl:apply-templates select="collection[@name =
$MyGroup]" />
</xsl:template>
<xsl:template match="/large-collection/collection">
<xsl:for-each select="ref">
<xsl:sort select="$MyParts/part[@id =
(current())/@refid]/@type" order="ascending"/>
<xsl:sort select="$MyParts/part[@id =
(current())/@refid]/@name" order="ascending"/>
type: <xsl:value-of
select="concat($MyParts/part[@id =
(current())/@refid]/@type, ' name: ',
$MyParts/part[@id = (current())/@refid]/@name, ' id:
', $MyParts/part[@id = (current())/@refid]/@id)"/>
</xsl:for-each>
</xsl:template>
</xsl:stylesheet>
Here's the output I get when I execute the XSLT using
MSXML3 DOM and processor:
type: type-a name: name-a id: 1
type: type-a name: name-b id: 2
type: type-b name: name-c id: 3
type: type-b name: name-e id: 5
type: type-b name: name-h id: 8
type: type-c name: name-f id: 6
type: type-c name: name-i id: 9
type: type-d name: name-d id: 4
type: type-d name: name-g id: 7
Here's the output I get when I execute the same XSLT
using MSXML4 DOM and processor:
type: type-a name: name-a id: 1
type: type-a name: name-b id: 2
type: type-b name: name-c id: 3
type: type-d name: name-d id: 4
type: type-b name: name-e id: 5
type: type-c name: name-f id: 6
type: type-d name: name-g id: 7
type: type-b name: name-h id: 8
type: type-c name: name-i id: 9
Possible workarounds:
1) Normally, one can avoid using the current function
call by simply using a key. That is not possible in
this case because XSLT does not allow you to form a
key from an outside document XML tree.
2) You could duplicate the data kept in
c:\temp\parts.xml in every dynamically-generated XML
document (by modifying the SOAP service that generates
the XML or by running an extra transform) but that
seems a little in-elegant!
3) You can revert back to MSXML3 or some other XSLT
processor that allows use of current() in an
xsl:sort/@select value.
4) You can wait for MSXML4 SP2
David Chryst
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