PHP Login and logout script and example

Depending on the visitors session condition whether logged in or not we can display different messages to the members.We should show an welcome messages to a logged in user like "Welcome john" with a logout button. Same way we if the member has not logged in then we can show login input box in that place or show the link to login page.
In PHP 5 and above the session checking has to be done line this

if(!isset($_SESSION['userid'])){
// session not logged in so display form

}else{
// session logged
}

Here is the code




if(isset($session[userid])){ // Member is logged in so we have to display welcome message with userid and one logout link
echo "

";

}else { // Member has not logged in so we can display the login form allowing member to login with user id and password

echo "

";

Welcome $session[userid]
LOGOUT
Username
Password
Forgot password

} // End of else condtiion

echo "";
?>

PHP Login Script (MORE DETAILED)

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.

Registration Page 1

// 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);
?>

Registered

Thank you, you have registered - you may now login.

Registration Page 2

}
else
{
?>

" method="post">

Username:
Password:
Confirm Password:

}
?>

The Login Page 1

// 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 ($check2 == 0) {
die('That user does not exist in our database. Click Here to Register');
}
while($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.');
}

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
?>

" method="post">

Login
Username:
Password:

}

?>

Members Area

// 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

";
echo "Your Content

";
echo "Logout";
}
}
}
else

//if the cookie does not exist, they are taken to the login screen
{
header("Location: login.php");
}
?>

Logout Page

$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");
?>