Creating XML files with DOM Document

As a first blog post I would like to have some attention for the fact that a lot of programmers are using functions and classes for doing exactly the same as what can be accomplished by using default PHP extensions.

XML files are very common nowadays and every developer needs to deal with them one day. Most of the scripts and classes used to generate XML files string use concatenation and echo to buildup XML files. Although this is a very short and quick method for simple XML files the same approach is often used with more complex XML files with namespaces. The code then often becomes bloated, unreadable and slow, so why not use the PHP 5 DOM API instead (or if you travelled from the past and still use PHP 4 try DOM XML). A quick example of the PHP 5 DOM API usage below.

An example XML:

	
		1
		
		03-12-2009
	

To generate this XML in an object oriented way we can use the following code:

// Define content of each event
$aEventNodes = array(
					'id'		=> 1,
					'title'		=> 'Using DOM Document',
					'datetime'	=> time());	
	
$document	= new DOMDocument('1.0', 'UTF-8');
					
// Create the root
$root		= $document->createElement('events');
$document->appendChild($root);

$eventElement = $document->createElement('event', '');
foreach($aEventNodes as $sKey=>$sValue) {
	$eventElement->appendChild($document->createElement($sKey, $sValue));
}
$root->appendChild($eventElement);

// Output the XML file
echo $document->saveXML();

First we create a document object, we add the XML version and encoding as arguments. Note on the encoding is that this encoding is only used in the XML header, not in values we will later add to our XML so you still need to use utf8_encode for example. Now that we have a document setup we can start appending elements to it. By calling saveXML() we will get a XML three dump as string.

Like I said this is a very simple example, the API is capable of much more.