Untitled

common.php:
<?php

session_start();

function registerUser($user,$pass1,$pass2){
	$errorText = '';

	// Check passwords
	if ($pass1 != $pass2) $errorText = "Passwords are not identical!";
	elseif (strlen($pass1) < 6) $errorText = "Password is to short!";

	// Check user existance
	$pfile = fopen("userpwd.txt","a+");
    rewind($pfile);

    while (!feof($pfile)) {
        $line = fgets($pfile);
        $tmp = explode(':', $line);
        if ($tmp[0] == $user) {
            $errorText = "The selected user name is taken!";
            break;
        }
    }

    // If everything is OK -> store user data
    if ($errorText == ''){
		// Secure password string
		$userpass = md5($pass1);

		fwrite($pfile, "\r\n$user:$userpass");
    }

    fclose($pfile);


	return $errorText;
}

function loginUser($user,$pass){
	$errorText = '';
	$validUser = false;

	// Check user existance
	$pfile = fopen("userpwd.txt","r");
    rewind($pfile);

    while (!feof($pfile)) {
        $line = fgets($pfile);
        $tmp = explode(':', $line);
        if ($tmp[0] == $user) {
            // User exists, check password
            if (trim($tmp[1]) == trim(md5($pass))){
            	$validUser= true;
            	$_SESSION['userName'] = $user;
            }
            break;
        }
    }
    fclose($pfile);

    if ($validUser != true) $errorText = "Invalid username or password!";

    if ($validUser == true) $_SESSION['validUser'] = true;
    else $_SESSION['validUser'] = false;

	return $errorText;
}

function logoutUser(){
	unset($_SESSION['validUser']);
	unset($_SESSION['userName']);
}

function checkUser(){
	if ((!isset($_SESSION['validUser'])) || ($_SESSION['validUser'] != true)){
		header('Location: login.php');
	}
}

?>

index.php:
<?php
	require_once('common.php');
	checkUser();
?>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "DTD/xhtml1-transitional.dtd">
<html>
<head>
   <title>Micro Login System</title>
   <link href="style/style.css" rel="stylesheet" type="text/css" />
</head>
<body>
    <div id="main">
      <div class="caption">Login System Demo Page</div>
      <div id="icon">&nbsp;</div>
      <div id="result">
		Hello <?php echo $_SESSION['userName']; ?> ! <br/>
		<p>This site demonstartes how to use Micro Login System.</p>
		<p><a href="logout.php"> To log out click here!</a></p>
	  </div>
	  <div id="source">Micro Login System v 1.0</div>
    </div>
</body>

login.php:
<?php
require_once('common.php');

$error = '0';

if (isset($_POST['submitBtn'])){
	// Get user input
	$username = isset($_POST['username']) ? $_POST['username'] : '';
	$password = isset($_POST['password']) ? $_POST['password'] : '';

	// Try to login the user
	$error = loginUser($username,$password);
}

?>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "DTD/xhtml1-transitional.dtd">
<html>
<head>
   <title>Micro Login System</title>
   <link href="style/style.css" rel="stylesheet" type="text/css" />
</head>
<body>
    <div id="main">
<?php if ($error != '') {?>
      <div class="caption">Site login</div>
      <div id="icon">&nbsp;</div>
      <form action="<?php echo $_SERVER['PHP_SELF']; ?>" method="post" name="loginform">
        <table width="100%">
          <tr><td>Username:</td><td> <input class="text" name="username" type="text"  /></td></tr>
          <tr><td>Password:</td><td> <input class="text" name="password" type="password" /></td></tr>
          <tr><td colspan="2" align="center"><input class="text" type="submit" name="submitBtn" value="Login" /></td></tr>
        </table>
      </form>

      &nbsp;<a href="register.php">Register</a>

<?php
}
    if (isset($_POST['submitBtn'])){

?>
      <div class="caption">Login result:</div>
      <div id="icon2">&nbsp;</div>
      <div id="result">
        <table width="100%"><tr><td><br/>
<?php
	if ($error == '') {
		echo "Welcome $username! <br/>You are logged in!<br/><br/>";
		echo '<a href="index.php">Now you can visit the index page!</a>';
	}
	else echo $error;

?>
		<br/><br/><br/></td></tr></table>
	</div>
<?php
    }
?>
	<div id="source">Micro Login System v 1.0</div>
    </div>
</body>

logout.php:
<?php
	require_once('common.php');
	logoutUser();
	header('Location: index.php');
?>

register.php:
<?php
	require_once('common.php');

	if (isset($_POST['submitBtn'])){
		// Get user input
		$username  = isset($_POST['username']) ? $_POST['username'] : '';
		$password1 = isset($_POST['password1']) ? $_POST['password1'] : '';
		$password2 = isset($_POST['password2']) ? $_POST['password2'] : '';

		// Try to register the user
		$error = registerUser($username,$password1,$password2);
	}
?>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "DTD/xhtml1-transitional.dtd">
<html>
<head>
   <title>Micro Login System</title>
   <link href="style/style.css" rel="stylesheet" type="text/css" />
</head>
<body>
    <div id="main">
<?php if ((!isset($_POST['submitBtn'])) || ($error != '')) {?>
      <div class="caption">Register user</div>
      <div id="icon">&nbsp;</div>
      <form action="<?php echo $_SERVER['PHP_SELF']; ?>" method="post" name="registerform">
        <table width="100%">
          <tr><td>Username:</td><td> <input class="text" name="username" type="text"  /></td></tr>
          <tr><td>Password:</td><td> <input class="text" name="password1" type="password" /></td></tr>
          <tr><td>Confirm password:</td><td> <input class="text" name="password2" type="password" /></td></tr>
          <tr><td colspan="2" align="center"><input class="text" type="submit" name="submitBtn" value="Register" /></td></tr>
        </table>
      </form>

<?php
}
    if (isset($_POST['submitBtn'])){

?>
      <div class="caption">Registration result:</div>
      <div id="icon2">&nbsp;</div>
      <div id="result">
        <table width="100%"><tr><td><br/>
<?php
	if ($error == '') {
		echo " User: $username was registered successfully!<br/><br/>";
		echo ' <a href="login.php">You can login here</a>';

	}
	else echo $error;

?>
		<br/><br/><br/></td></tr></table>
	</div>
<?php
    }
?>
	<div id="source">Micro Login System v 1.0</div>
    </div>
</body>