Question

I have an XML file and the data is passed through parameters, like so:

<node id="a" title="Title A">
    <node id="b"  title="Title B">
       <node id="c"  title="Title C">
       </node>
    </node>
    <node id="d"  title="Title D">
    </node>
</node>

How can I loop recursively through this XML and print only the ID of every node in a list? i.e.

<ul>
   <li>a</li>
   <ul>
      <li>b</li>
      <ul>
         <li>c</li>
      </ul>
   </ul>
   <ul>
      <li>d</li>
   </ul>
</ul>

Answer 1

Although it would be possible without xslt, I think this is more reusable:

<?php
$dom = new DOMDocument();
$dom->loadXml('<node id="a" title="Title A">
    <node id="b"  title="Title B">
       <node id="c"  title="Title C">
       </node>
    </node>
    <node id="d"  title="Title D">
    </node>
</node>');


$xsl = new DOMDocument;
$xsl->loadXml('<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
    <xsl:template match="/">
        <ul><xsl:apply-templates /></ul>
    </xsl:template>

    <xsl:template match="node">
        <li><xsl:value-of select="@title" /> (<xsl:value-of select="@id" />)
            <xsl:if test="count(descendant::node) > 0">
                <ul><xsl:apply-templates /></ul>
            </xsl:if>
        </li>
    </xsl:template>
</xsl:stylesheet>', LIBXML_NOCDATA);

$xslt = new XSLTProcessor();
$xslt->importStylesheet($xsl);

echo $xslt->transformToXML($dom);