How To Make a Login System for Your Website

This is a simple login system that has been very reliable and secure for me. I use it myself on my websites, when a simple login system is needed. If you know a little of MySQL and PHP, it is very easy to use.

First, you will need MySQL instaled in your computer. I have XAMMP instaled and I use PHPmyADMIN for accessing my databases. They are free for download; just search for them online. You also need to create a database in your MySQL. And as you proceed, remember that linux server file names are always case sensitives. LOGIN.PHP is not equal to login.php like on WINDOWS servers.

1. Run this SQL command in your MySQL database (you must have one):

   CREATE TABLE `users` (
   `id` int(3) NOT NULL auto_increment,
   `login` varchar(8) default NULL,
   `password` varchar(8) default NULL,
   PRIMARY KEY (`id`)
   ) TYPE=MyISAM AUTO_INCREMENT=3 ;

   This will create the table that will record the usernames and passwords.

2. Then, create the LOGIN.PHP file. This page will contain the form that will submit the user´s data.

   <?
   session_name("MyLogin");
   session_start();
   session_destroy();

   if($_GET['login'] == "failed") {
   print $_GET['cause'];
   }
   ?>
   <form name="login_form" method="post" action="log.php?action=login">
   Login: <input type="text" name="user"><BR>
   Password: <input type="password" name="pwd"><BR>
   <input type="submit">
   </form>

3. Now, create the LOG.PHP. This is the file that performs the action of the form.

   <?
   session_name("MyLogin");
   session_start();

   if($_GET['action'] == "login") {
   $conn = mysql_connect("localhost","user","password"); // your MySQL connection data
   $db = mysql_select_db("DATABASENAME"); //put your database name in here
   $name = $_POST['user'];
   $q_user = mysql_query("SELECT * FROM USERS WHERE login='$name'");

   if(mysql_num_rows($q_user) == 1) {
   
   $query = mysql_query("SELECT * FROM USERS WHERE login='$name'");
   $data = mysql_fetch_array($query);
   if($_POST['pwd'] == $data['password']) {
   session_register("name");
   header("Location: yourpage.php"); // success page. put the URL you want
   exit;
   } else {
   header("Location: login.php?login=failed&cause=".urlencode('Wrong Password'));
   exit;
   }
   } else {
   header("Location: login.php?login=failed&cause=".urlencode('Invalid User'));
   exit;
   }
   }

   // if the session is not registered
   if(session_is_registered("name") == false) {
   header("Location: login.php");
   }
   ?>

4. If you had enough attention, you noticed that the login will lead the user to YOURPAGE.PHP. Add these lines of code to all your pages that you want to secure (including yourpage.php):

   <?
   require("log.php");
   ?>

   Printing the user name in the screen is very easy. Just add this code:

   <? print $_SESSION["name"]; ?>

That´s it. It works out fine, but if you have any trouble with it, please contact me!!!