Rename an XML node using PHP

Question

I'm trying to figure out how to rename a node in XML using PHP?

I Have come this far:

$dom = new DOMDocument( '1.0' );
$dom->preserveWhiteSpace = false;
$dom->formatOutput = true;

// load the xml file
$dom->loadXML( '<?xml version="1.0" encoding="ISO-8859-1"?>
<library>
  <data>
    <invite>
      <username>jmansa</username>
      <userid>1</userid>
    </invite>
    <update>1</update>
  </data>
</library>', LIBXML_NOBLANKS );
$xpath = new DOMXPath($dom);

//find all 'data' nodes.
$node = $xpath->query("//data");

// if found
if( $node->length ) {
    foreach ($node as $n) {
       // RENAME HERE? //
    }
}

echo "<xmp>". $dom->saveXML() ."</xmp>";

Now, I want to rename <data> to <invites>. Can this be done and if yes, how?

jimp · Accepted Answer · 2013-02-26 17:00:52Z

1

A Node's name ("data" or "invites" respectively) cannot be renamed via the DOM because the Node::nodeName property is read-only.

You can create a new node named "invites", append it before the "data" node, move the children of "data" to the new "invites" node, remove the "data" node, and then output the tree to get your result.

Example:

<?php
// Create a test document.
    $dom = new DOMDocument( '1.0' );
    $dom->preserveWhiteSpace = false;
    $dom->formatOutput = true;

// Load the xml file.
    $dom->loadXML('<?xml version="1.0" encoding="ISO-8859-1"?'.'>
    <library>
      <data attr1="1" attr2="2">
        <invite>
          <username>jmansa</username>
          <userid>1</userid>
        </invite>
        <update>1</update>
      </data>
    </library>', LIBXML_NOBLANKS );
    $xpath = new DOMXPath($dom);

    // Convert <data> to <invites>.
    if ($dataNode = $xpath->query("/library/data")->item(0))
    {
    // Create the <invites> node.
        $invitesNode = $dom->createElement('invites');
        $dataAttrs   = $dataNode->attributes;
        foreach ($dataAttrs as $dataAttr)
        {   $invitesNode->setAttributeNodeNS($dataAttr->cloneNode());   }
        $dom->documentElement->appendChild($invitesNode);

    // Move the <data> children over.
        if ($childNodes = $xpath->query("/library/data/*"))
        {
            foreach ($childNodes as $childNode)
            {   $invitesNode->appendChild($childNode);  }
        }

    // Remove <data>.
        $dataNode->parentNode->removeChild($dataNode);
    }

// Test the result.
    echo $dom->saveXML();
?>

edited Feb 26, 2013 at 17:00

answered Sep 17, 2012 at 16:39

jimp

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8 Comments

Mansa Over a year ago

Wow... That sounds like a bit of work... Can't str_replace be used in some way?

jimp Over a year ago

It's not that bad. I'll edit my post with an example. I wouldn't advise using str_replace unless you are absolutely certain <data> and later </data> will only exist in that specific context (rare).

Mansa Over a year ago

Ok, allthough I'm pretty sure it will allways be as in example. Looking forward to your example :-)

jimp Over a year ago

Example added. Notice that I really only added three sections after starting with your code. Hopefully it will help.

Mansa Over a year ago

It works allmnost perfect!? If there is no <data> field it adds an <invites>?

|

feklee · Accepted Answer · 2013-02-27 11:04:39Z

My solution, with extended test case:

// Changes the name of element $element to $newName.
function renameElement($element, $newName) {
  $newElement = $element->ownerDocument->createElement($newName);
  $parentElement = $element->parentNode;
  $parentElement->insertBefore($newElement, $element);

  $childNodes = $element->childNodes;
  while ($childNodes->length > 0) {
    $newElement->appendChild($childNodes->item(0));
  }

  $attributes = $element->attributes;
  while ($attributes->length > 0) {
    $attribute = $attributes->item(0);
    if (!is_null($attribute->namespaceURI)) {
      $newElement->setAttributeNS('http://www.w3.org/2000/xmlns/',
                                  'xmlns:'.$attribute->prefix,
                                  $attribute->namespaceURI);
    }
    $newElement->setAttributeNode($attribute);
  }

  $parentElement->removeChild($element);
}

function prettyPrint($d) {
  $d->formatOutput = true;
  echo '<pre>'.htmlspecialchars($d->saveXML()).'</pre>';
}

$d = new DOMDocument( '1.0' );
$d->loadXML('<?xml version="1.0"?>
<library>
  <data a:foo="1" x="bar" xmlns:a="http://example.com/a">
    <invite>
      <username>jmansa</username>
      <userid>1</userid>
    </invite>
    <update>1</update>
  </data>
</library>');

$xpath = new DOMXPath($d);
$elements = $xpath->query('/library/data');
if ($elements->length == 1) {
  $element = $elements->item(0);
  renameElement($element, 'invites');
}

prettyPrint($d);

By the way, I added this solution as a comment to the PHP documentation for DOMElement.

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