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persistent objects in PHP?

Within some applications it is necessary to store data of complete objects for later use. Unfortunately there is no buildin solution as far as I know. One simple way is to hand the storing and restoring over to the object itself. So I created a base class which is able to create itself either from the current session if available or completly new when no session has been started yet. This is a kind of a workaround but it is easy and working well.

Note: For get_called_class() a PHP version of minimum 5.3.0 is required.

Here is my persistent base class

* This is my persistent php object base class
* -------------------------------------------
* how to use it:
* 1. derive a class via "extends" (see example)
* 2. call $obj = MyObject::createPersistent( 'abcd' );
* 3. use the $obj as you want it is now stored automatically!
* 4. don't belive it? try it!
class SessionObject{

var $storageName;
var $className;

function __construct(){

// save this or derived objects on destruction
function __destruct(){

* a call to this static function searches in the session
* for the desired object or alternatively creates a new object
* of this kind
static function createPersistent( $objectID ){
$class = get_called_class();
$storageName = $class.'_ID_'.$objectID;

if (array_key_exists($storageName, $_SESSION)){
echo 'Restored '.$storageName.'';
return $_SESSION[$storageName];
} else {
echo 'create '.$class.' with ID '.$objectID.'';
$temp = new $class();
return $temp;

// internal store function
function store(){
$_SESSION[$this->storageName] = $this;
echo "Stored ".$this->storageName.'';


Now an persistent object could be as simple as this

* my demo object
class MyObject extends SessionObject{

var $test;

function __construct(){
$this->test = 10;


and the creation call of the object is here

 // here is the magic : create the object
$obj = MyObject::createPersistent( 'abcd' );

Thats it! Now just use the object as usal. All members are beeing stored automatically in the base class.

Download the complete demo : SessionObjectDemo.php


based on a template by jimmy