51
I want to make sure all users those login are different in a time either on the same or different computer or web browser. Following are sample of my program which consist 4 different pages;
[PHP]
#users.php
$users = array(
'user1' => md5('password1'),
'user2' => md5('password2')
);
$salt = substr(md5(date('F')), 8);
[/PHP]
[PHP]
<?php
#login.php
if($_SERVER['REQUEST_METHOD'] == 'POST')
{
if(!ereg('^[A-Za-z0-9]', $_POST['username']))
{
exit('<p>Invalid characters in the username.</p>');
}
else
{
$username = $_POST['username'];
$password = md5($_POST['password']);
require('users.php');
if(array_key_exists($username, $users))
{
//the username exists
//compare the submitted password to value of the array key (the right password)
if($password == $users[$username])
{
//password is correct
session_start();
$_SESSION['usr'] = $username;
$_SESSION['loggedin'] = md5($username.$password.$salt);
setcookie(session_name(), $_COOKIE[session_name()], time()+7200, '/');
header('Location: home.php');
exit;
}
else
{
exit('<p>Invalid password.</p>');
}
}
else
{
exit('<p>Invalid username.</p>');
}
}
}
?>
<html>
<head>
<title>Login Form</title>
</head>
<body>
<form method="post" action="login.php">
Username: <input type="text" name="username"><br />
Password: <input type="password" name="password"><br />
<input type="submit" name="submit" value="Login">
</form>
</body>
</html>
[/PHP]
[PHP]
#check.php
session_start();
if(!isset($_SESSION['loggedin']))
{
header('Location: login.php');
exit;
}
else
{
//the session variable exists, check it's valid:
require('users.php');
$userexists = false;
foreach($users as $username => $password)
{
if(md5($username.$password.$salt) == $_SESSION['loggedin'])
{
$userexists = true;
}
}
if($userexists !== true)
{
exit('<p>Invalid session: please <a href="login.php">login</a>.</p>');
}
}
[/PHP]
[PHP]
<?php
require('check.php');
?>
<html>
<head>
<title>User Home Page</title>
</head>
<body>
<p><a href="logout.php">Logout</a></p>
<p>Your username is : <?php echo $_SESSION['usr'] ?></p>
</body>
</html>
[/PHP]
