XML parsing in XSLT

bsudhindra · October 8th, 2012, 06:12 AM

Hi,

I need a generic XML parser (pref. SAX implementation) in XSLT.

What I basically need to do is, given an XML document, I need an output which represents the tags, tag-depth, tag-value, attributes, attribute value in a delimited string format.

Any help would be appreciated.

Cheers

mhkay · October 8th, 2012, 06:37 AM

Why would you need an XML parser in XSLT to achieve this? All the information you require is available in the tree model generated by a standard XML parser.

You just need a stylesheet that does something along the lines of

Code:

<xsl:output method="text()"/>
<xsl:template match="*">
  name=<xsl:value-of select="name()"/>
  depth=<xsl:value-of select="count(ancestor::*)"/>
  attributes=(<xsl:apply-templates select="@*"/>)
</xsl:template>
<xsl:template match="@*">
  name=<xsl:value-of select="name()"/>
  value=<xsl:value-of select="."/>
</xsl:template>

etc.

bsudhindra · October 8th, 2012, 06:53 AM

Hi,

Thanks for the quick reply; I have modified your code slightly as follows..

Code:

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">
<xsl:output method="text()"/>
<xsl:template match="*">
  <xsl:for-each select="//node()">
  name=<xsl:value-of select="name()"/>
  depth=<xsl:value-of select="count(ancestor::*)"/>
  attributes=(<xsl:apply-templates select="@*"/>)
  </xsl:for-each>
</xsl:template>
<xsl:template match="@*">
  name=<xsl:value-of select="name()"/>
  value=<xsl:value-of select="."/>
</xsl:template>
</xsl:stylesheet>

The source XML I use is this..

Code:

<?xml version="1.0"?>
<catalog>
   <book id="bk101">
      <author>Gambardella, Matthew</author>
      <title>XML Developer's Guide</title>
      <genre>Computer</genre>
      <price>44.95</price>
      <publish_date>2000-10-01</publish_date>
      <description>An in-depth look at creating applications 
      with XML.</description>
   </book>
   <book id="bk102">
      <author>Ralls, Kim</author>
      <title>Midnight Rain</title>
      <genre>Fantasy</genre>
      <price>5.95</price>
      <publish_date>2000-12-16</publish_date>
      <description>A former architect battles corporate zombies, 
      an evil sorceress, and her own childhood to become queen 
      of the world.</description>
   </book>
</catalog>

And the output I get from the XSL is this..

Code:

  name=catalog
  depth=0
  attributes=()
  
  name=
  depth=1
  attributes=()
  
  name=book
  depth=1
  attributes=(
  name=id
  value=bk101)

In the above output, I miss value of tags themselves, e.g. publish_date

It would be great if you could help me with this..

Thanks & cheers

samjudson · October 8th, 2012, 07:13 AM

The issue here is how you understand XML, and what a text node is. node() returns all the nodes under a element, even if they are text nodes. * only returns which element nodes (which does not include text nodes).

Try this on for size:

Code:

<xsl:output method="text"/>
<xsl:strip-space elements="*"/>

<xsl:template match="*">
  name=<xsl:value-of select="name()"/>
  depth=<xsl:value-of select="count(ancestor::*)"/>
  attributes=(<xsl:apply-templates select="@*"/>)
  value=<xsl:value-of select="normalize-space(text()[1])"/>
  <xsl:text>
</xsl:text>
<xsl:apply-templates select="*"/>
  
</xsl:template>
<xsl:template match="@*">name=<xsl:value-of select="name()"/>,value=<xsl:value-of select="."/></xsl:template>

mhkay · October 8th, 2012, 07:19 AM

It's not at all clear to me what form you want the output to take, but I would think that somewhere in the template match="*" you want to process the children of the element by calling xsl:apply-templates.

bsudhindra · October 8th, 2012, 07:31 AM

@samjudson & mkhay

Thanks agian, the latest modified code is as follows

Code:

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">
	<xsl:output method="text" />
	<xsl:strip-space elements="*" />
	<xsl:template match="*">
		<xsl:for-each select="//node()">
			name = 	<xsl:value-of select="name()" />
			depth = <xsl:value-of select="count(ancestor::*)" />
			attributes = (<xsl:apply-templates select="@*" />)
			value = <xsl:value-of select="normalize-space(text()[1])" />
			<xsl:text>
	</xsl:text>
		</xsl:for-each>
		<xsl:apply-templates select="*" />
	</xsl:template>
	<xsl:template match="@*">
				name = <xsl:value-of select="name()" />
				value = <xsl:value-of select="." />
	</xsl:template>
</xsl:stylesheet>

This works almost perfect, except that when the tag depth is counted, the end-tags (e.g. </Id>) is also counted in and the depth is increased, this shouldn't happen - any idea how can I avoid this?

The sample output I get is this..and as you see, the depth is increased for all end-tags

Code:

			name = 	catalog
			depth = 0
			attributes = ()
			value = 
	
			name = 	book
			depth = 1
			attributes = (
				name = id
				value = bk101)
			value = 
	
			name = 	author
			depth = 2
			attributes = ()
			value = Gambardella, Matthew
	
			name = 	
			depth = 3
			attributes = ()
			value = 
	
			name = 	title
			depth = 2
			attributes = ()
			value = XML Developer's Guide
	
			name = 	
			depth = 3
			attributes = ()
			value =