Creating a file based login system

Step 9.
Let's summarise the complete content of the common.php file.

<?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($pfile, "rn$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');
 }
}

?>
Step 10.
As final step let's create a test page to demonstarte the system is working.

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

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "DTD/xhtml1-transitional.dtd">
<html>
<body>
 Login System Demo Page
 Hello <?php echo $_SESSION['userName']; ?> ! 
 This site demonstartes how to use Login System.
 <a href="logout.php"> To log out click here!</a>
</body>
[/html]

article index
page 1 : untitled page
page 2 : Part 2
page 3 : Part 3
page 4 : Part 4
page 5 - current : Part 5

Tags: