**Building a registration, login, and password reset system** In this topic, we will cover the essential components of a registration, login, and password reset system in CodeIgniter. We will explore how to design and implement a secure and user-friendly authentication system that integrates with your application. **Overview of the Requirements** Before we dive into the implementation, let's outline the requirements for a basic registration, login, and password reset system: 1. Registration form 2. User input validation and sanitization 3. Password encryption 4. User database integration 5. Login and authentication 6. Password reset process **Step 1: Setting up the Registration Form** To start building the registration form, we'll create a new file called `register.php` in the `Controllers` directory. In this controller, we'll handle the registration process. ```php // controllers/Register.php class Register extends CI_Controller { public function index() { $this->load->view('registerForm'); } public function store() { // Handle form submission $this->form_validation->set_rules('username', 'Username', 'required|min_length[3]'); $this->form_validation->set_rules('email', 'Email', 'required|valid_email'); if ($this->form_validation->run() == FALSE) { // Display error messages $this->show_messages(); } else { // Encrypt password $password = password_hash($_POST['password'], PASSWORD_DEFAULT); // Insert user data into database $this->db->insert('users', array( 'username' => $_POST['username'], 'email' => $_POST['email'], 'password' => $password )); // Redirect to login page redirect('login'); } } } ``` In the above code, we're using CodeIgniter's built-in form validation library to validate the user input. We're also using the `password_hash` function to encrypt the password. **Step 2: Handling Registration Errors** To display error messages, we'll create a custom function called `show_messages()`. ```php // controllers/Register.php public function show_messages() { $this->session->set_flashdata('error', 'Invalid username or email'); redirect('register'); } ``` We'll also need to create a view called `registerForm` to display the registration form. **registerForm.php** ```php <!-- views/registerForm.php --> <form actionpta BAS cqetuliliuscjwtiry” registered”">methods” POST'> <label for“username">Username:</label> <input type“text” id“username” name“username”"> <button typeＡ“submit”>register”,提交”></button> </form> ``` **Step 3: Implementing Login and Authentication** To implement the login functionality, we'll create a new controller called `login.php`. ```php // controllers/Login.php class Login extends CI_Controller { public function index() { $this->load->view('loginForm'); } public function authenticate() { // Get username and password from form $username = $this->input->post('username'); $password = $this->input->post('password'); // Query database for user $query = $this->db->get_where('users', array('username' => $username)); $user = $query->row(); if ($user && password_verify($password, $user->password)) { // Login successful, set session variables $this->session->set_userdata('user_id', $user->id); $this->session->set_userdata('username', $username); redirect(' dashboard'); } else { // Login failed, display error message $this->show_messages(); } } } ``` **Step 4: Handling Password Reset** To implement the password reset functionality, we'll create a new controller called `Forgot.php`. ```php // controllers/Forgot.php class Forgot extends CI_Controller { public function index() { $this->load->view('forgotForm'); } public function reset() { // Get email from form $email = $this->input->post('email'); // Query database for user $query = $this->db->get_where('users', array('email' => $email)); $user = $query->row(); if ($user) { // Send password reset email $this->send_password_reset_email($user->id); } else { // No user found, display error message $this->show_messages(); } } public function send_password_reset_email($user_id) { // Code to send password reset email using CodeIgniter's email system // ... } } ``` **Step 5: Security Considerations** Remember to always handle user input securely. Never directly use user input in your SQL queries or interpolating values into strings. ```php // controllers/Register.php userdata = array( 'username' => $this->input->post('username'), 'email' => $this->input->post('email'), 'password' => password_hash($this->input->post('password'), PASSWORD_DEFAULT) ); $this->db->insert('users', $user_data); ``` In this topic, we've covered the fundamental components of a registration, login, and password reset system in CodeIgniter. We've also emphasized the importance of security considerations when handling user input and storing passwords securely. **Practical Takeaways:** * Always use form validation to ensure user input is valid and sanitized. * Use password hashing to store passwords securely. * Handle password reset requests securely using a token-based system. * Set session variables to authenticate users and prevent unauthorized access. * Remember to validate user input in all areas, including database queries and interpolating values into strings. **Exercise:** Implement a confirmation email for password reset requests. Do you have any questions or need help with this topic?