PHP Login Script

1
The Database

We are going to create a simple login system using PHP code on our pages, and a MySQL database to store our users information. We will track the users who are logged in with cookies.

Before we can create a login script, we first need to create a database to store users. For the purpose of this tutorial we will simply need the fields "username" and "password", however you can create as many fields as you wish.

 

 CREATE TABLE users (ID MEDIUMINT NOT NULL AUTO_INCREMENT PRIMARY KEY, username VARCHAR(60), password VARCHAR(60)) 

This will create a database called

users

with 3 fields: ID, username, and password.

2
Registration Page 1

 <?php 
 // Connects to your Database 

 mysql_connect("your.hostaddress.com", "username", "password") or die(mysql_error()); 

 mysql_select_db("Database_Name") or die(mysql_error()); 


 //This code runs if the form has been submitted

 if (isset($_POST['submit'])) { 



 //This makes sure they did not leave any fields blank

 if (!$_POST['username'] | !$_POST['pass'] | !$_POST['pass2'] ) {

 		die('You did not complete all of the required fields');

 	}



 // checks if the username is in use

 	if (!get_magic_quotes_gpc()) {

 		$_POST['username'] = addslashes($_POST['username']);

 	}

 $usercheck = $_POST['username'];

 $check = mysql_query("SELECT username FROM users WHERE username = '$usercheck'") 

or die(mysql_error());

 $check2 = mysql_num_rows($check);



 //if the name exists it gives an error

 if ($check2 != 0) {

 		die('Sorry, the username '.$_POST['username'].' is already in use.');

 				}


 // 
this makes sure both passwords entered match

 	if ($_POST['pass'] != $_POST['pass2']) {

 		die('Your passwords did not match. ');

 	}



 	// here we encrypt the password and add slashes if needed

 	$_POST['pass'] = md5($_POST['pass']);

 	if (!get_magic_quotes_gpc()) {

 		$_POST['pass'] = addslashes($_POST['pass']);

 		$_POST['username'] = addslashes($_POST['username']);

 			}



 // now we insert it into the database

 	$insert = "INSERT INTO users (username, password)

 			VALUES ('".$_POST['username']."', '".$_POST['pass']."')";

 	$add_member = mysql_query($insert);

 	?>



 
 <h1>Registered</h1>

 <p>Thank you, you have registered - you may now login</a>.</p>

 

Script continued and explained on the next page.

3
Registration Page 2

 <?php 
 } 

 else 
 {	
 ?>


 
 <form action="<?php echo $_SERVER['PHP_SELF']; ?>" method="post">

 <table border="0">

 <tr><td>Username:</td><td>

 <input type="text" name="username" maxlength="60">

 </td></tr>

 <tr><td>Password:</td><td>

 <input type="password" name="pass" maxlength="10">

 </td></tr>

 <tr><td>Confirm Password:</td><td>

 <input type="password" name="pass2" maxlength="10">

 </td></tr>

 <tr><th colspan=2><input type="submit" name="submit" 
value="Register"></th></tr> </table>

 </form>


 <?php

 }
 ?> 


The full code can be found on GitHub: https://github.com/Goatella/Simple-PHP-Login

If the form has not been submitted, they are shown the registration form, which collects the username and password.Basically what this does is check to see if the form has been submitted. If it has been submitted it checks to make sure that the data is all OK (passwords match, username isn't in use) as documented in the code. If everything is OK it adds the user to the database, if not it returns the appropriate error.

4
The Login Page 1

 <?php 

 // Connects to your Database 

 mysql_connect("your.hostaddress.com", "username", "password") or die(mysql_error()); 

 mysql_select_db("Database_Name") or die(mysql_error()); 


 //Checks if there is a login cookie

 if(isset($_COOKIE['ID_my_site']))


 //if there is, it logs you in and directes you to the members page

 { 
 	$username = $_COOKIE['ID_my_site']; 

 	$pass = $_COOKIE['Key_my_site'];

 	 	$check = mysql_query("SELECT * FROM users WHERE username = '$username'")or die(mysql_error());

 	while($info = mysql_fetch_array( $check )) 	

 		{

 		if ($pass != $info['password']) 

 			{

 			 			}

 		else

 			{

 			header("Location: members.php");



 			}

 		}

 }


 //if the login form is submitted 

 if (isset($_POST['submit'])) { // if form has been submitted



 // makes sure they filled it in

 	if(!$_POST['username'] | !$_POST['pass']) {

 		die('You did not fill in a required field.');

 	}

 	// checks it against the database



 	if (!get_magic_quotes_gpc()) {

 		$_POST['email'] = addslashes($_POST['email']);

 	}

 	$check = mysql_query("SELECT * FROM users WHERE username = '".$_POST['username']."'")or die(mysql_error());



 //Gives error if user dosen't exist

 $check2 = mysql_num_rows($check);

 if ($check2 == 0) {

 		die('That user does not exist in our database. <a href=add.php>Click Here to Register</a>');

 				}

 while($info = mysql_fetch_array( $check )) 	

 {

 $_POST['pass'] = stripslashes($_POST['pass']);

 	$info['password'] = stripslashes($info['password']);

 	$_POST['pass'] = md5($_POST['pass']);



 //gives error if the password is wrong

 	if ($_POST['pass'] != $info['password']) {

 		die('Incorrect password, please try again.');

 	}

 

Script continued and explained on the next page.

5
The Login Page 2

 else 

 { 

 
 // if login is ok then we add a cookie 

 	 $_POST['username'] = stripslashes($_POST['username']); 

 	 $hour = time() + 3600; 

 setcookie(ID_my_site, $_POST['username'], $hour); 

 setcookie(Key_my_site, $_POST['pass'], $hour);	 

 

 //then redirect them to the members area 

 header("Location: members.php"); 

 } 

 } 

 } 

 else 

{	 

 

 // if they are not logged in 

 ?> 

 <form action="<?php echo $_SERVER['PHP_SELF']?>" method="post"> 

 <table border="0"> 

 <tr><td colspan=2><h1>Login</h1></td></tr> 

 <tr><td>Username:</td><td> 

 <input type="text" name="username" maxlength="40"> 

 </td></tr> 

 <tr><td>Password:</td><td> 

 <input type="password" name="pass" maxlength="50"> 

 </td></tr> 

 <tr><td colspan="2" align="right"> 

 <input type="submit" name="submit" value="Login"> 

 </td></tr> 

 </table> 

 </form> 

 <?php 

 } 

 

 ?> 

 

The full code can be found on GitHub: https://github.com/Goatella/Simple-PHP-Login

This script first checks to see if the login information is contained in a cookie on the users computer. If it is, it tries to log them in. If this is successful they are redirected to the members area.

If there is no cookie, it allows them to login. If the form has been submitted, it checks it against the database and if it was successful sets a cookie and takes them to the members area. If it has not been submitted, it shows them the login form.

6
Members Area

 <?php 

 // Connects to your Database 

 mysql_connect("your.hostaddress.com", "username", "password") or die(mysql_error()); 

 mysql_select_db("Database_Name") or die(mysql_error()); 

 
 //checks cookies to make sure they are logged in 

 if(isset($_COOKIE['ID_my_site'])) 

 { 

 	$username = $_COOKIE['ID_my_site']; 

 	$pass = $_COOKIE['Key_my_site']; 

 	 	$check = mysql_query("SELECT * FROM users WHERE username = '$username'")or die(mysql_error()); 

 	while($info = mysql_fetch_array( $check )) 	 

 		{ 

 

 //if the cookie has the wrong password, they are taken to the login page 

 		if ($pass != $info['password']) 

 			{ 			header("Location: login.php"); 

 			} 

 

 //otherwise they are shown the admin area	 

 	else 

 			{ 

 			 echo "Admin Area<p>"; 

 echo "Your Content<p>"; 

 echo "<a href=logout.php>Logout</a>"; 

 			} 

 		} 

 		} 

 else 

 

 //if the cookie does not exist, they are taken to the login screen 

 {			 

 header("Location: login.php"); 

 } 

 ?> 


This code checks our cookies to make sure the user is logged in, the same way the login page did. If they are logged in, they are shown the members area. If they are not logged in they are redirected to the login page.

Be sure to download the full code on GitHub: https://github.com/Goatella/Simple-PHP-Login

7
Logout Page

 <?php 

 $past = time() - 100; 

 //this makes the time in the past to destroy the cookie 

 setcookie(ID_my_site, gone, $past); 

 setcookie(Key_my_site, gone, $past); 

 header("Location: login.php"); 

 ?> 

All our logout page does is

destroy the cookie

, and then direct them back to the login page. We destroy the cookie by setting the expiration to some time in the past.