facebook_subscribe2.php

<?php

define('VERIFY_TOKEN', 'yourappssecret');                                    
$method = $_SERVER['REQUEST_METHOD'];                             

if ($method == 'GET' && $_GET['hub_mode'] == 'subscribe' && $_GET['hub_verify_token'] == VERIFY_TOKEN) {
   echo $_GET['hub_challenge'];
} else if ($method == 'POST') {

   if ( isset( $_SERVER['HTTP_X_HUB_SIGNATURE'] ) ) {
	$post_body = file_get_contents("php://input");
	
	if ($_SERVER['HTTP_X_HUB_SIGNATURE'] == "sha1=" . hash_hmac('sha1', $post_body, VERIFY_TOKEN)) {
	
		//Connect To Database
        	$hostname='Your host address';
        	$username='Your username';
        	$password='Your password';
        	$dbname='Your database name';

        	mysql_connect($hostname,$username, $password) OR DIE ('Unable to connect to database! Please try again later.');
        	mysql_select_db($dbname) or die(mysql_error());

		$object = json_decode($post_body, true);

		foreach($object->entry as $update)
		{
        	// For each entry in notification, insert a row of information into the table "FaceBook"
		$changed_fields = $update->changed_fields[0];

		$result = mysql_query("INSERT INTO FaceBook (uid, id, time, changed_fields) VALUES('$update->uid', '$update->id', '$update->time', '$changed_fields')")
         	or die(mysql_error());
	
        	}

		mysql_close();
		}
   	}
}

?>