Login klasse

config.php


<?
// Connect to mysql
mysql_connect("localhost", "root", "");
mysql_select_db("database");

// Allow sessions
session_start();

// include classes
include("user.class.php");

?>

index.php


<?
include("config.php");


switch ($_REQUEST["mode"]) {
case "login":
    if (User::login($_REQUEST["username"], $_REQUEST["password"])) {
        header("Location: ".$_SERVER["PHP_SELF"]);
    } else {
        header("Location: ".$_SERVER["PHP_SELF"]."?invalid=1");
    }
    exit;
    
    
case "logout":    
    User::logout();
    header("Location: ".$_SERVER["PHP_SELF"]);
    exit;


default:
    

    if ($_SESSION["user"]) {
        ?>
        <html>
        <head><title>Login demo</title>
        </head>
        <body>
        Hej <?=$_SESSION["user"]["name"]?>! Du er logget ind. <a href="?mode=logout">Log ud</a>
        </body>
        </html>
        <?
        
        
    } else {
        ?>
        <html>
        <head><title>Login demo</title>
        </head>
        <body>
            <?
            if (isset($_REQUEST["invalid"])) {
                ?>
                Fejl ved login.<br>
                <br>
                <?
            }
            ?>
            <form action="<?=$_SERVER["PHP_SELF"]?>" method="post">
                <label for="username">Brugernavn</label><br>
                <input type="text" id="username" name="username"><br>
                <br>
                <label for="password">Adgangskode</label><br>
                <input type="password" id="password" name="password"><br>
                <br>
                <input type="hidden" name="mode" value="login">
                <input type="submit" value="Log ind">
            </form>
        </body>
        <?
    }
}
?>

user.class.php


<?
class User {
    
    function login($username, $password) {
        $username = strtolower($username);
        $password = md5(strtolower($password)); // Use encrypted password
        
        $res_users = mysql_query("SELECT * FROM users WHERE username='".$username."' AND password='".$password."'");
        if ($row_users = mysql_fetch_array($res_users)) {
            // OK
            $_SESSION["user"] = array(
                "id" => $row_users["ID"],
                "name" => $row_users["username"]
            );
            return true;
        }
        // Error
        return false;
    }
    
    function logout() {
        unset($_SESSION["user"]);
    }
}
?>

user.sql

CREATE TABLE IF NOT EXISTS `users` (
  `ID` int(11) NOT NULL auto_increment,
  `username` varchar(255) NOT NULL default '',
  `password` varchar(255) NOT NULL default '',
  PRIMARY KEY  (`ID`)
);