Tutorial to create a login system using HTML, PHP, and MySQL

This is a tutorial for creating a login system with the help of HTML, PHP, and MySQL. Your website needs to be dynamic and your visitors need to have instant access to it. Therefore, they want to log in as many times as possible. The login authentication system is very common for any web application. It allows registered users to access the website and members-only features. It is also helpful when we want to store information for users. It covers everything from shopping sites, educational sites, and membership sites, etc.


This tutorial is covered in 4 parts.


Table of Contents


  1. Signup System
  2. Login System
  3. Welcome Page
  4. Logout Script

1) Building a Signup system


In this part, We will create a signup system that allows users to create a new account to the system. Our first step is to create a HTML registration form. The form is pretty simple to create. It only asks for a name, email, password, and confirm password. Email addresses will be unique for every user. Multiple accounts for the same email address are not allowed. It will show an error message to the users who try to create multiple accounts with the same email address.


Step 1: Creating Registration Form in HTML


We will create a PHP file named register.php with the following code in it. This is a simple HTML form with some basic validation. If you are not familiar with HTML then you can get it from many online sites who give ready-made html5 login form templates.


<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>Sign Up</title>
        <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/css/bootstrap.min.css">
    </head>
    <body>
        <div class="container">
            <div class="row">
                <div class="col-md-12">
                    <h2>Register</h2>
                    <p>Please fill this form to create an account.</p>
                    <form action="" method="post">
                        <div class="form-group">
                            <label>Full Name</label>
                            <input type="text" name="name" class="form-control" required>
                        </div>    
                        <div class="form-group">
                            <label>Email Address</label>
                            <input type="email" name="email" class="form-control" required />
                        </div>    
                        <div class="form-group">
                            <label>Password</label>
                            <input type="password" name="password" class="form-control" required>
                        </div>
                        <div class="form-group">
                            <label>Confirm Password</label>
                            <input type="password" name="confirm_password" class="form-control" required>
                        </div>
                        <div class="form-group">
                            <input type="submit" name="submit" class="btn btn-primary" value="Submit">
                        </div>
                        <p>Already have an account? <a href="login.php">Login here</a>.</p>
                    </form>
                </div>
            </div>
        </div>    
    </body>
</html>

The output of the above HTML form will look like this.


Sign Up

All the input fields are required by adding the "required" attribute which is the default HTML attribute. The use of type="email" will validate the email address provided by users and gives an error if the email address is not valid. For the registration form, we have used bootstrap for rapid development. If you want to save your time on HTML code you can always use some free html5 templates for your project.


Step 2: Creating the MySQL Database Table


You will need to create a new database with any suitable name you want. After that please execute the below SQL query to create the user's table inside your newly created MySQL database.


CREATE TABLE `users` (
  `id` int(11) unsigned NOT NULL AUTO_INCREMENT,
  `name` varchar(75) NOT NULL,
  `password` varchar(255) NOT NULL,
  `email` varchar(100) NOT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `email` (`email`)
) ENGINE=InnoDB  DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci AUTO_INCREMENT=1;

Step 3: Creating Database Configuration File


Now, we have created the users table. Let's create a new PHP file named config.php to connect with the MySQL database. Paste the following code in the config.php file and change the database name to whatever you choose while creating the database.


<?php
define('DBSERVER', 'localhost'); // Database server
define('DBUSERNAME', 'root'); // Database username
define('DBPASSWORD', ''); // Database password
define('DBNAME', 'demo'); // Database name
 
/* connect to MySQL database */
$db = mysqli_connect(DBSERVER, DBUSERNAME, DBPASSWORD, DBNAME);
 
// Check db connection
if($db === false){
    die("Error: connection error. " . mysqli_connect_error());
}
?>

Step 4: Creating a Session File


Let's create a file named session.php. In this file, we will start the session and check if a user is already logged in, if yes then we will redirect the user to welcome.php file.


<?php
// Start the session
session_start();

// if the user is already logged in then redirect user to welcome page
if (isset($_SESSION["userid"]) && $_SESSION["userid"] === true) {
    header("location: welcome.php");
    exit;
}
?>

Step 5: Create Registration Form in PHP


Finally, it's time to create a PHP code that allows users to register their accounts into the system. This PHP code will alert users with an error if any user is already registered with the same email address.


Replace the following code in the register.php file.


<?php

require_once "config.php";
require_once "session.php";

if ($_SERVER["REQUEST_METHOD"] == "POST" && isset($_POST['submit'])) {

    $fullname = trim($_POST['name']);
    $email = trim($_POST['email']);
    $password = trim($_POST['password']);
    $confirm_password = trim($_POST["confirm_password"]);
    $password_hash = password_hash($password, PASSWORD_BCRYPT);

    if($query = $db->prepare("SELECT * FROM users WHERE email = ?")) {
        $error = '';
        // Bind parameters (s = string, i = int, b = blob, etc), in our case the username is a string so we use "s"
	$query->bind_param('s', $email);
	$query->execute();
	// Store the result so we can check if the account exists in the database.
	$query->store_result();
        if ($query->num_rows > 0) {
            $error .= '<p class="error">The email address is already registered!</p>';
        } else {
            // Validate password
            if (strlen($password ) < 6) {
                $error .= '<p class="error">Password must have atleast 6 characters.</p>';
            }

            // Validate confirm password
            if (empty($confirm_password)) {
                $error .= '<p class="error">Please enter confirm password.</p>';
            } else {
                if (empty($error) && ($password != $confirm_password)) {
                    $error .= '<p class="error">Password did not match.</p>';
                }
            }
            if (empty($error) ) {
                $insertQuery = $db->prepare("INSERT INTO users (name, email, password) VALUES (?, ?, ?);");
                $insertQuery->bind_param("sss", $fullname, $email, $password_hash);
                $result = $insertQuery->execute();
                if ($result) {
                    $error .= '<p class="success">Your registration was successful!</p>';
                } else {
                    $error .= '<p class="error">Something went wrong!</p>';
                }
            }
        }
    }
    $query->close();
    $insertQuery->close();
    // Close DB connection
    mysqli_close($db);
}
?>
<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>Sign Up</title>
        <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/css/bootstrap.min.css">
    </head>
    <body>
        <div class="container">
            <div class="row">
                <div class="col-md-12">
                    <h2>Register</h2>
                    <p>Please fill this form to create an account.</p>
                    <?php echo $success; ?>
                    <?php echo $error; ?>
                    <form action="" method="post">
                        <div class="form-group">
                            <label>Full Name</label>
                            <input type="text" name="name" class="form-control" required>
                        </div>    
                        <div class="form-group">
                            <label>Email Address</label>
                            <input type="email" name="email" class="form-control" required />
                        </div>    
                        <div class="form-group">
                            <label>Password</label>
                            <input type="password" name="password" class="form-control" required>
                        </div>
                        <div class="form-group">
                            <label>Confirm Password</label>
                            <input type="password" name="confirm_password" class="form-control" required>
                        </div>
                        <div class="form-group">
                            <input type="submit" name="submit" class="btn btn-primary" value="Submit">
                        </div>
                        <p>Already have an account? <a href="login.php">Login here</a>.</p>
                    </form>
                </div>
            </div>
        </div>    
    </body>
</html>

Once user click on submit button it will check if $_SERVER["REQUEST_METHOD"] == "POST" and $_POST['submit'] variable has been set. For security concerns, we always suggest not to store the password as plain text in the database. We have used password_hash() function which creates a new password hash using a strong one-way hashing algorithm.


The above PHP script will validate that no user is registered with the same email address and also validate password. After validation is confirmed we store the user-provided information in the users' table and alert the user that registration was successful.


2) Building a Login System


In this part, we will create a login form to allow users to access the restricted area of the system. In our case, the restricted area is a welcome page which we will cover in the next part.


Step 1: Creating a Login Form in HTML


Below is the Login Form in HTML. Paste it in a file named login.php


<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>Login</title>
        <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/css/bootstrap.min.css">
    </head>
    <body>
        <div class="container">
            <div class="row">
                <div class="col-md-12">
                    <h2>Login</h2>
                    <p>Please fill in your email and password.</p>
                    <form action="" method="post">
                        <div class="form-group">
                            <label>Email Address</label>
                            <input type="email" name="email" class="form-control" required />
                        </div>    
                        <div class="form-group">
                            <label>Password</label>
                            <input type="password" name="password" class="form-control" required>
                        </div>
                        <div class="form-group">
                            <input type="submit" name="submit" class="btn btn-primary" value="Submit">
                        </div>
                        <p>Don't have an account? <a href="register.php">Register here</a>.</p>
                    </form>
                </div>
            </div>
        </div>    
    </body>
</html>

The output of the above code will look like this


Login

Step 2: Creating a Login System in PHP


After creating the login form in HTML, we will write a code to validate login credentials. On form submit we will check that the email and password are filled. If they filled then we will execute a SELECT query to find the record in a database on the basis of email and password. If any record found, then we will store the "userID" in session and the user is redirected to the welcome.php file, otherwise, the user is alerted with an error message.


Let's replace the following code in the login.php file.


<?php

require_once "config.php";
require_once "session.php";


$error = '';
if ($_SERVER["REQUEST_METHOD"] == "POST" && isset($_POST['submit'])) {

    $email = trim($_POST['email']);
    $password = trim($_POST['password']);

    // validate if email is empty
    if (empty($email)) {
        $error .= '<p class="error">Please enter email.</p>';
    }

    // validate if password is empty
    if (empty($password)) {
        $error .= '<p class="error">Please enter your password.</p>';
    }

    if (empty($error)) {
        if($query = $db->prepare("SELECT * FROM users WHERE email = ?")) {
            $query->bind_param('s', $email);
            $query->execute();
            $row = $query->fetch();
            if ($row) {
                if (password_verify($password, $row['password'])) {
                    $_SESSION["userid"] = $row['id'];
                    $_SESSION["user"] = $row;

                    // Redirect the user to welcome page
                    header("location: welcome.php");
                    exit;
                } else {
                    $error .= '<p class="error">The password is not valid.</p>';
                }
            } else {
                $error .= '<p class="error">No User exist with that email address.</p>';
            }
        }
        $query->close();
    }
    // Close connection
    mysqli_close($db);
}
?>
<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>Login</title>
        <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/css/bootstrap.min.css">
    </head>
    <body>
        <div class="container">
            <div class="row">
                <div class="col-md-12">
                    <h2>Login</h2>
                    <p>Please fill in your email and password.</p>
                    <?php echo $error; ?>
                    <form action="" method="post">
                        <div class="form-group">
                            <label>Email Address</label>
                            <input type="email" name="email" class="form-control" required />
                        </div>    
                        <div class="form-group">
                            <label>Password</label>
                            <input type="password" name="password" class="form-control" required>
                        </div>
                        <div class="form-group">
                            <input type="submit" name="submit" class="btn btn-primary" value="Submit">
                        </div>
                        <p>Don't have an account? <a href="register.php">Register here</a>.</p>
                    </form>
                </div>
            </div>
        </div>    
    </body>
</html>

3) Creating a Welcome Page


Below is the code for the welcome.php file. Users will be redirected to this page after a successful login process. We have added some code at the top of the page to check if the user is not logged in, then redirect the user to the login page.


Let's create a welcome.php file and paste the following code in it.


<?php
// start the session
session_start();

// Check if the user is not logged in, then redirect the user to login page
if (!isset($_SESSION["userid"]) || $_SESSION["userid"] !== true) {
    header("location: login.php");
    exit;
}
?>
<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>Welcome <?php echo $_SESSION["name"]; ?></title>
        <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/css/bootstrap.min.css">
    </head>
    <body>
        <div class="container">
            <div class="row">
                <div class="col-md-12">
                    <h1>Hello, <strong><?php echo $_SESSION["name"]; ?></strong>. Welcome to demo site.</h1>
                </div>
                <p>
                    <a href="logout.php" class="btn btn-secondary btn-lg active" role="button" aria-pressed="true">Log Out</a>
                </p>
            </div>
        </div>
    </body>
</html>

4) The Logout script


Finally, Let's create a logout.php file with the following code in it.


<?php
// Start the session
session_start();

// Destroy the session.
if (session_destroy()) {
    // redirect to the login page
    header("Location: login.php");
    exit;
}
?>

Once the user clicks on the Log Out link, the above script, will be called to destroy the session and redirect user to the login.php file.


Conclusion


In this tutorial, I explained how you can create a Login System using HTML, PHP and MySQL. Once you understand how simple it is to create a login system you can add other features like reset password, forgot password, verify email address, edit user's profile, etc.

Tags:
html5, html, php, mysql, php development

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