Modify XML attribute PHP DOM

Question

I have an XML file that looks like this.

<collections id="my collections">
 <category id="my category">
   <record id="my record">
     <title>Some Info</title>
   </record>
 </category>
</collections>

I am looking for away to replace any attribute in the above XML file with a new attribute,Using PHP DOM and Xpath. Any help is highly appreciated

Answer 1

Not sure what you want to do exactly, but the general idea is :

• You must instanciate DOMDocument
• and load your XML strings with it : DOMDocument::loadXML
• Then, you must instanciate DOMXpath on that document
• And use it to query the document : DOMXPath::query
• One you have found the node that interests you, you can manipulate it
  • for example, you can set the value of an attribute : DOMElement::setAttribute

Here, for example, you could use some thing like this :

$str = <<<XML
    <collections id="My Collections">
     <category id="my category">
       <record id="my record">
         <title>Some Info</title>
       </record>
     </category>
    </collections>
XML;

$dom = new DOMDocument();
$dom->loadXML($str);

$xpath = new DOMXPath($dom);
$elements = $xpath->query('//record[@id="my record"]');
if ($elements->length >= 1) {
    $element = $elements->item(0);
    $element->setAttribute('id', "glop !");
}
echo '<pre>' . htmlspecialchars($dom->saveXML()) . '</pre>';

This will replace the id attribute my record, on the node that's identified by it, by "glop !", and you'd get the following XML as output :

<?xml version="1.0"?>
<collections id="My Collections">
     <category id="my category">
       <record id="glop !">
         <title>Some Info</title>
       </record>
     </category>
    </collections>