None of my XPath select statements will work going against an XML file with a default namespace. Help!

by Mark Bosley

Back in college, on the night before a final exam, every subject humanity has ever considered became utterly fascinating to me. Every subject that is, except the subject about which I was to be tested on the next morning. My wife says she would end up cleaning the night before an exam. And me? I would end up in the library reading the Encyclopaedia Britannica, leafing through it page by page. I felt good about ignoring my exam the next day if I ended up studying a subject that I was to study the next semester.

Well, things haven't changed that much. I was recently stuck with an XPath problem and so what did I do? Well, I read the XSLT 2 requirements document. Never mind that it will be at least a year until we see any implementation of XSLT 2.0, it just that it was so fascinating. My procrastination this time, however, actually paid off.

The Problem

I was working with the following XML DOM being returned via ServerXMLHTTP. It has two namespaces: one associated with the prefix cs and one with no prefix, which is called a 'default' namespace. 

The XML Dom being returned was from outside my company, I had to deal with it. I had so much trouble that I investigated programmatically removing a namespace.

This proved to be very hard-because it is impossible. Another person on the project put the DOM into a string, removed the namespace and then reloaded the DOM. This seemed too kludgey and slow for me.

What follows is the xml dom and the stylesheet I was trying to use. This resulted in <root></root> but not in <root><gotHere>.....

<requestHierarchySelectResult resultName="" 
	xmlns="http://www.lightcc.com/ns"
	xmlns:cs="http://www.customsolids.com">
    <request>
        <created_dt>05/05/2000 00:00:00</created_dt>
        <created_tm>01/01/1900 14:02:46</created_tm>
        <cs:request_id>100002</cs:request_id>
    </request>
</requestHierarchySelectResult>

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">
<xsl:template match="/">
	<root><xsl:apply-templates  select="/*/request"/></root>
</xsl:template>

<xsl:template  match="*|@*|node()"/>

<xsl:template  match="request">
   <gotHere><xsl:value-of  select="."/></gotHere>
</xsl:template>

</xsl:stylesheet>

I thought I came to a solution when I realized I needed the namespaces in the XML file also declared in the stylesheet. So, I added the namespaces to the style sheet from the xml file. But, it still did not produce <root><gotHere>......

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0"	
	xmlns="http://www.lightcc.com/ns"
	xmlns:cs="http://www.customsolids.com">
<xsl:template match="/">
	<root><xsl:apply-templates  select="/*/request"/></root>
</xsl:template>

<xsl:template  match="*|@*|node()"/>

<xsl:template  match="request">
   <gotHere><xsl:value-of  select="."/></gotHere>
</xsl:template>

</xsl:stylesheet>

I could get something with unwieldy XPath queries like <xsl:apply-templates select="*/*[local-name()='request']"/>

But, to do a whole stylesheet like that would be a chore.

An answer from Dimitre Novatchev, helped the lights go on.

The problem is that I did not understand that namespaces link an XML and XSLT file thru the URI, not the prefix. So the (simple) solution is to add a prefix in the xslt file and then use the prefix in the XPath statements (lc in the stylesheet below) 

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0"	
	xmlns:lc	="http://www.lightcc.com/ns"
	xmlns:cs="http://www.customsolids.com">
<xsl:template match="/">
	<root><xsl:apply-templates  select="/*/lc:request"/></root>
</xsl:template>

<xsl:template  match="*|@*|node()"/>

<xsl:template  match="lc:request">
   <gotHere><xsl:value-of  select="."/></gotHere>
</xsl:template>

</xsl:stylesheet>

Although the answer from Dimitre helped, it wasn't until I read the requirements document for the next version of XSLT. Here is the relevant portion.

So, in conclusion, reading the requirements documents will help you understand the roadblocks that a wide range of programmer's are running into.

Below are links for the requirements documents for XSLT 2.0 and XPath 2.0

http://www.w3.org/TR/xslt20req

http://www.w3.org/TR/xpath20req