Parsing an XML File to Retrieve Data

PHP actually provides a number of different ways to access the data from an XML document. The XML, XMLReader, and DOM XML extensions all offer different unique ways in which to navigate through an XML document. Each has its own benefits and drawbacks, and is worth investigating. However, PHP 5 adds another extension, known as SimpleXML. This extension, as it sounds, makes it simple to access XML data and therefore will be the manner this book uses.

SimpleXML at its heart is one of two functions: simplexml_load_string(), which operates on an XML document already saved into a PHP variable, and simplexml_load_file(), which does the same from a file. Upon calling one of these functions SimpleXML returns an object that replicates the XML document. Each XML tag becomes a property of the object, nested accordingly. Perhaps the best way to illustrate this is via an example.

Reading XML Files with SimpleXML

<?php
// Using SimpleXML, read the file into memory:
$xml = simplexml_load_file('contacts.xml');

// Let's print out a formatted version of some of this contact data:
// Start with an ordered list:
echo "<ol>\n";

// Loop over each contact:
foreach ($xml->contact as $c) {
    // Print their name:
    echo '<li>' . $c->name;

    // Now start an Unordered list for their phone numbers:
    echo '<ul>';

    // Loop over every phone number for this person:
    foreach ($c->phone as $p) {
        // Echo out a line including the type of number:
        // The attribute will be accesible as if it were an assoc array
        // entry.  Using the entry itself, will echo it's value.
        echo '<li>', ucfirst($p['type']), ': ', $p, '</li>';
    }

    // Close off the phone list:
    echo "</ul></li>\n";
}
?>

Hope it helps.