Question

I’m using simpleXML to add in a child node within one of my XML documents… when I do a print_r on my simpleXML object, the < is still being displayed as a < in the view source. However, after I save this object back to XML using DOMDocument, the < is converted to < and the > is converted to >

Any ideas on how to change this behavior? I’ve tried adding dom->substituteEntities = false;, but this did no good.

    //Convert SimpleXML element to DOM and save
    $dom = new DOMDocument('1.0');
    $dom->preserveWhiteSpace = false;
    $dom->formatOutput = false;
    $dom->substituteEntities = false;
    $dom->loadXML($xml->asXML());
    $dom->save($filename);

Here is where I’m using the <:

$new_hint = '<![CDATA[' . $value[0] . ']]>';               
$PrintQuestion->content->multichoice->feedback->hint->Passage->Paragraph->addChild('TextFragment', $new_hint);

The problem, is I’m using simple XML to iterate through certain nodes in the XML document, and if an attribute matches a given ID, a specific child node is added with CDATA. Then after all processsing, I save the XML back to file using DOMDocument, which is where the < is converted to &lt, etc.

Here is a link to my entire class file, so you can get a better idea on what I’m trying to accomplish. Specifically refer to the hint_insert() method at the bottom.

http://pastie.org/1079562

Answer 1

SimpleXML and php5’s DOM module use the same internal representation of the document (facilitated by libxml). You can switch between both apis without having to re-parse the document via simplexml_import_dom() and dom_import_simplexml().
I.e. if you really want/have to perform the iteration with the SimpleXML api once you’ve found your element you can switch to the DOM api and create the CData section within the same document.

<?php
$doc = new SimpleXMLElement('<a>
  <b id="id1">a</b>
  <b id="id2">b</b>
  <b id="id3">c</b>
</a>');


foreach( $doc->xpath('b[@id="id2"]') as $b ) {
  $b = dom_import_simplexml($b);
  $cdata = $b->ownerDocument->createCDataSection('0<>1');
  $b->appendChild($cdata);
  unset($b);
}

echo $doc->asxml();

prints

<?xml version="1.0"?>
<a>
  <b id="id1">a</b>
  <b id="id2">b<![CDATA[0<>1]]></b>
  <b id="id3">c</b>
</a>