Authentication Class

Database Layout:
CREATE TABLE `gebruikers` (
  `gebruikerid` int(6) NOT NULL auto_increment,
  `gebruikersnaam` varchar(50) NOT NULL,
  `voornaam` varchar(40) NOT NULL,
  `tussenvoegsel` varchar(25) NOT NULL,
  `achternaam` varchar(40) NOT NULL,
  `wachtwoord` varchar(40) NOT NULL,
  `niveau` int(6) NOT NULL,

    PRIMARY KEY  (`gebruikerid`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=2 ;


Database Connect('config.php')
<?php
session_start();

//Userlevels:

define('BANNED', 0);
define('QUEST', 1);
define('USER', 2);
define('VIP', 3);
define('REDACTEUR', 4);
define('MODERATOR', 5);
define('SUPERMODERATOR', 6);
define('ADMIN', 7);

include('clsAuthentication.php');
$db = new PDO('mysql:host=localhost;dbname=test', $user, $pass);
try
{
	$Auth = new Authentication($db);
}
catch(Exception $e)
{
	echo 'Message: ' .$e->getMessage();
}
?>


Voorbeeld('index.php');
<?php
include('config.php');
$Auth->setRequiredAuth(QUEST);
$Auth->login('Gebruikersnaam', 'Wachtwoord');
?>


Classe ('clsAuthentication.php')
<?php
class Authentication
{
	static $db;
	private $m_sSaltkey;
	protected $m_aUserdata = array();
	
	function __construct($p_oDatabaseConnection)
	{
		if(is_object($p_oDatabaseConnection))
		{
			$this->db = $p_oDatabaseConnection;
		}
		else
		{
			throw new Exception('Geen database Connection ?');
			exit;
		}
		$this->getLoginStatus();
	}
	
	public function login($p_sUsername, $p_sPassword)
	{
		$p_sUsername = $this->db->quote($p_sUsername);
        $p_sPassword = $this->db->quote($p_sPassword);
		if(!isset($_SESSION['user_id']))
		{
			if($this->getUserdata($p_sUsername, $p_sPassword))
			{
				$_SESSION['login_time'] = time();
				$_SESSION['user_id'] = $this->m_aUserdata['gebruikerid'];
				$_SESSION['server_generated'] = true;
				$_SESSION['username'] = $this->m_aUserdata['gebruikersnaam'];
				$_SESSION['ip_adress'] = $_SERVER['REMOTE_ADDR'];
				$_SESSION['user_agent'] = $_SERVER['HTTP_USER_AGENT'];
				$_SESSION['auth_lvl'] = $this->aUserdata['niveau'];
			}
		}
		else
		{
			throw new Exception('Je bent al ingelogd');
		}
	}
	private function validateSession()
	{
		if(($_SERVER['REMOTE_ADDR'] != $_SESSION['ip_adress']) or ($_SERVER['HTTP_USER_AGENT'] != $_SESSION['user_agent']) or empty($_SESSION['server_generated']))
		{
			$this->logout();
			throw new Exception('Sessie informatie corrupt');
			return false;
		}
		return true;
	}
	
	private function getLoginStatus()
	{
		if(isset($_SESSION['user_id']))
		{
			if($this->validateSession())
			{
				return true;
			}
		}
		return false;
	}
	
	
	function setRequiredAuth($p_nRequired)
	{
		if($this->getLoginStatus())
		{
			if($_SESSION['auth_lvl'] < $p_nRequired)
			{
				echo 'Je hebt niet genoeg rechten om hier te mogen komen'; 
				exit;
			} 
		}
		else
		{
			if($p_nRequired > 1)
			{
				echo 'Je moet ingelogd zijn en de benodigede rechten hebben om hier te mogen komen';
				exit;
			}
		}
		return true;
	}
	
	private function getSaltkey()
	{
		if(is_file("salt.key") and is_readable("salt.key"))
		{
			$filePointer =  fopen('salt.key', 'r');
			$this->m_sSaltkey = fread($filePointer, 40);
			fclose($filePointer);
		}
		else
		{
			$filePointer = fopen('salt.key', 'w+');
			$aRange = range('A', 'z');
			shuffle($aRange);
			$sSaltkey = sha1(implode('', $aRange));
			fwrite($filePointer, $sSaltkey);
			chmod('salt.key', 660);
			$this->getSaltkey(); //recall it self to load 'new'
		}
	}
	
	private function getUserdata($p_sUsername, $p_sPassword)
	{
		$aSql = $this->db->query("
			SELECT *
			FROM gebruikers
			WHERE LOWER(gebruikersnaam) = LOWER('".$p_sUsername."') AND wachtwoord = '".sha1(sha1($p_sPassword).$this->m_sSaltkey)."'
			LIMIT 1");
		if(!is_null($aSql))
		{
			$this->m_aUserdata = $aSql;
		}
		else
		{
			throw new Exception('Gebruikersnaam of Wachtwoord fout');
			return false;
		}
		return true;
	}	
	
	public function logout()
	{
		if(isset($_SESSION['user_id']))
		{
			session_destroy();
			return true;		
		}
		throw new Exception('Je kunt niet uitloggen als je niet bent ingelogd');
		return false;
	}
}
?>