Using XML and XSL together

[Caroline M]

Hi there,

I am developing an XML-based messaging application that has to support
several versions of the message specification. The way I am doing that
is by using XSLT to transform messages from one version into another.

Here's a dummy example that I am using for my unit tests:

<?xml version="1.0"?>
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform" >
<xsl:template match="/mos">
<xsl:copy>
<xsl:for-each select="*">
<xsl:copy-of select="."/>
</xsl:for-each>
<version_2.8>2.8.1</version_2.8>
</xsl:copy>
</xsl:template>
</xsl:stylesheet>

This just adds a new element with version information after the others.
This works fine. The trouble comes when I want one of these that only
works on a specific type of message and I wanted to embed the name of
the message into the XSL file. I read up on embedding XML inside XSL
files and read that you could do it by putting the XSL into a separate
namespace. So here is an example of how I am doing that:

<?xml version="1.0"?>
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:mos="http://example.com/mos_data">
<mos:message_type>listMachInfo</mos:message_type>
<xsl:template match="/mos">
<xsl:copy>
<xsl:for-each select="*">
<xsl:copy-of select="."/>
</xsl:for-each>
<version_3.0>3.1</version_3.0>
</xsl:copy>
</xsl:template>
</xsl:stylesheet>

To load these files we use a library that was developed internally as a
wrapper around libxml. Its possible I'm using the library incorrectly
but I want to eliminate bad syntax first. I can parse the above files
successfully as both an ordinary XML document, and as an XSL document.
But what I am trying to do is get hold of the data in the
mos:message_type element. We have a function called
"locate_single_node" which takes an XPath expression and a list of
namespaces:

Here's the expression I use:

pxmlNode = pxmlDoc->locate_single_node("/mos:message_type", ns);

where ns is a list of namespaces in the document. However, the node is
not found. Any ideas?

Many thanks,

Caroline M

 

[Caroline M]

<xsl:stylesheet version="1.0"

xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:mos="http://example.com/mos_data">
<mos:message_type>listMachInfo</mos:message_type>
<xsl:template match="/mos">
<xsl:copy>
<xsl:for-each select="*">
<xsl:copy-of select="."/>
</xsl:for-each>
<version_3.0>3.1</version_3.0>
</xsl:copy>
</xsl:template>
</xsl:stylesheet>

Responding to my own post... you may have noticed the lack of
indentation with the above file. This is because of the way it is
generated programatically by my test code. One of the consequences is
that it is difficult to see the hierarchy when looking at it and I
fotgot that the mos:message_type node was inside the xsl:stylesheet
node. Once I fixed that the code worked

Caroline M.