PHP how to make authentication

Learn how to create a secure authentication system with PHP and MySQL. Follow a step-by-step guide to understand the process with a practical example.

Creating Authentication with PHP

Creating authentication with PHP is a simple process that involves several steps. The following example outlines the necessary steps for creating a basic user authentication system.

Step 1: Create the Database

The first step is to create the database that will store the user's credentials. This includes all of the information that will be used to authenticate the user, such as their username, email address, and password. The following code can be used to create the database:


CREATE DATABASE authentication;

USE authentication;

CREATE TABLE users(
  user_id INT(11) AUTO_INCREMENT PRIMARY KEY,
  username VARCHAR(50) NOT NULL,
  email VARCHAR(50) NOT NULL,
  password VARCHAR(255) NOT NULL
);

Step 2: Create the Registration Form

The next step is to create a registration form which the user can use to create an account. This form will require the user to enter their desired username, email address, and password. The following code can be used to create a basic registration form:


<form action="register.php" method="post">
  <input type="text" name="username" placeholder="Username">
  <input type="email" name="email" placeholder="Email">
  <input type="password" name="password" placeholder="Password">
  <input type="submit" value="Register">
</form>

Step 3: Create the register.php File

The next step is to create a file called register.php which will process the information submitted by the user. This file will need to connect to the database and check if the username or email address is already in use. If the username and email address are available, the user's information will be inserted into the database. The following code can be used to create the register.php file:


<?php
  // Connect to the database
  $db = mysqli_connect('localhost', 'username', 'password', 'authentication');

  // Check if the form is submitted
  if (isset($_POST['register'])) {
    // Get the form data
    $username = mysqli_real_escape_string($db, $_POST['username']);
    $email = mysqli_real_escape_string($db, $_POST['email']);
    $password = mysqli_real_escape_string($db, $_POST['password']);

    // Check if the username or email address is already in use
    $sql = "SELECT * FROM users WHERE username='$username' OR email='$email'";
    $result = mysqli_query($db, $sql);
    if (mysqli_num_rows($result) > 0) {
      echo "Username or email address is already in use.";
    } else {
      // Insert the user into the database
      $sql = "INSERT INTO users (username, email, password)
              VALUES ('$username', '$email', '$password')";
      if (mysqli_query($db, $sql)) {
        echo "User registered successfully.";
      } else {
        echo "Error: " . $sql . "<br>" . mysqli_error($db);
      }
    }
  }
?>

Step 4: Create the Login Form

The next step is to create a login form which the user can use to log into their account. This form will require the user to enter their username and password. The following code can be used to create a basic login form:


<form action="login.php" method="post">
  <input type="text" name="username" placeholder="Username">
  <input type="password" name="password" placeholder="Password">
  <input type="submit" value="Login">
</form>

Step 5: Create the login.php File

The next step is to create a file called login.php which will process the information submitted by the user. This file will need to connect to the database and check if the username and password match any records in the database. If the username and password match, the user will be logged in. The following code can be used to create the login.php file:


<?php
  // Connect to the database
  $db = mysqli_connect('localhost', 'username', 'password', 'authentication');

  // Check if the form is submitted
  if (isset($_POST['login'])) {
    // Get the form data
    $username = mysqli_real_escape_string($db, $_POST['username']);
    $password = mysqli_real_escape_string($db, $_POST['password']);

    // Check if the username and password match any records in the database
    $sql = "SELECT * FROM users WHERE username='$username' AND password='$password'";
    $result = mysqli_query($db, $sql);
    if (mysqli_num_rows($result) > 0) {
      // Start a session
      session_start();

      // Store the user's information in the session
      $_SESSION['username'] = $username;

      // Redirect the user to the home page
      header('location: home.php');
    } else {
      echo "Username or password is incorrect.";
    }
  }
?>

By following these steps, a basic user authentication system can be created with PHP. This system can then be expanded to include additional features such as email verification, two-factor authentication, and password reset.

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