gistfile1.php

<?php        

ob_start();
session_save_path("/tmp");
$sid = md5(uniqid());


class CustomReadHandler extends SessionHandler {
	public function read($session_id) 
	{
		return strval(file_get_contents(session_save_path() . '/sess_' . $session_id));
	}
}


session_set_save_handler(new CustomReadHandler(), true);

$handler = new CustomReadHandler();


session_name('sessionname');
session_id($sid);
session_start();
//$this->assertEmpty($_SESSION);
var_dump(empty($_SESSION));
$_SESSION['sessiondata'] = 'foo';
var_dump($_SESSION);
session_write_close();

var_dump($handler->read($sid));