How to make authorization in PHP

Learn how to create user authentication in PHP with a step-by-step example. Create secure and reliable authentication easily.

Using PHP for Authorization

Authorization is one of the most important aspects of web application development, and PHP is a great language for implementing it. PHP offers a wide range of tools for implementing authorization, from simple session-based authentication to OAuth-based authorization. In this article, we'll look at how to use PHP for authorization with a simple example.

We'll start by setting up a basic authentication system with a form and a login page. To do this, we'll need to create a form on our login page with two fields: a username and a password. We'll also need to create a PHP script that will check the credentials that the user has entered against a database of valid users.

First, let's create the form. We'll use the following code to create the form:

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

This code will create a form with two fields: a username and a password. The form will be submitted to the login.php script when the user clicks the "Login" button.

Now let's create the login.php script. This script will check the credentials that the user has entered against a database of valid users. We'll use the following code to do this:

<?php
// Check if the form has been submitted
if (isset($_POST["username"]) && isset($_POST["password"])) {
  
  // Get the username and password from the form
  $username = $_POST["username"];
  $password = $_POST["password"];
  
  // Connect to the database
  $db = new mysqli("localhost", "username", "password", "database");
  if ($db->connect_error) {
    die("Connection failed: " . $db->connect_error);
  }
  
  // Query the database for a user with the given username and password
  $query = "SELECT * FROM users WHERE username = '$username' AND password = '$password'";
  $result = $db->query($query);
  
  // If a user was found, set session variables and redirect to the home page
  if ($result->num_rows > 0) {
    session_start();
    $_SESSION["logged_in"] = true;
    $_SESSION["username"] = $username;
    header("Location: home.php");
  }
  
  // If no user was found, redirect back to the login page
  else {
    header("Location: login.php");
  }
  
  // Close the connection
  $db->close();
}
?>

This code will check the credentials that the user has entered against a database of valid users. If a user is found with the given username and password, the script will set session variables and redirect the user to the home page. If no user is found, the user will be redirected back to the login page.

That's it! We've just created a basic authentication system with a form and a login page using PHP. This system can be easily extended to use more advanced authentication methods such as OAuth, as well as additional features such as a forgot password page. PHP provides a wide range of tools for implementing authorization, and this example should give you a good starting point for your own projects.