Simplify the task of creating XML documents with the XML_Serializer class, which lets you build nested XML documents from PHP data structures like arrays and objects (and vice versa). I'll show you how to build an XML document tree via the XML_Serializer class from PEAR, how to programmatically create an XML document from an array or an object, how to attach attributes to elements, and how to customize the behavior of the serializer. All this, and much, much more!
Good things come in twos: Mickey and Donald, Tom and Jerry, yin and yang. It's no surprise then that XML_Serializer has a doppelganger of its own. Called XML_Unserializer, this class can take an XML document and convert it into a series of nested PHP structures, suitable for use in a PHP script.
In order to understand how this works, consider the following XML document:
<?xml version='1.0'? > <library> <book id="MFRE001"> <title>The Adventures of Sherlock Holmes</title> <author>Arthur Conan Doyle</author> <price currency="USD">24.95</price> </book> <book id="MFRE002"> <title>Life of Pi</title> <author>Yann Martel</author> <price currency="USD">7.99</price> </book> <book id="MFRE003"> <title>Europe on a Shoestring</title> <author>Lonely Planet</author> <price currency="USD">16.99</price> </book> </library>
Now, in order to convert this XML document into a PHP structure, simply put XML_Unserializer to work on it, as below:
// include class file include("Unserializer.php");
// unserialize the document $result = $unserializer->unserialize("library.xml", true);
// dump the result $data = $unserializer->getUnserializedData(); print_r($data);
Here, the unserialize() method accepts either a string containing XML data or an XML file (set the second argument to false or true depending on which one you are passing) and returns a PHP structure representing the XML document. Here's what the output looks like:
( [book] => Array (  => Array ( [title] => The Adventures of Sherlock Holmes [author] => Arthur Conan Doyle [price] => 24.95 )
 => Array ( [title] => Life of Pi [author] => Yann Martel [price] => 7.99 )
 => Array ( [title] => Europe on a Shoestring [author] => Lonely Planet [price] => 16.99 ) ) )
Now, in order to access the title of the third book (for example), you would use the notation
which would return
Europe on a Shoestring
Note that XML_Unserializer uses the type hints generated in the serialization process to accurately map XML elements to PHP data types. If these hints are unavailable (as in the example above), XML_Unserializer will "guess" the type of each value. A look at the source code of the class reveals that "complex structures will be arrays and tags with only CData in them will be strings."