**Course Title:** Mastering CodeIgniter Framework: Fast, Lightweight Web Development **Section Title:** Forms, Validation, and Session Management **Topic:** Handling forms and user input in CodeIgniter In this topic, we will explore how to handle forms and user input in CodeIgniter, including implementing form validation and managing user sessions. This is an essential aspect of web development, and understanding how to do it correctly is crucial for building secure and reliable web applications. **Understanding Form Input in CodeIgniter** When a user submits a form, you need to validate their input data to ensure it meets your application's requirements. CodeIgniter provides the `Form_validation` library, which makes it easy to implement form validation. **Required Concepts and Tools** To implement form validation, you will need to understand the following concepts: * **Validators**: These are functions that check the input data against specific criteria. CodeIgniter provides several built-in validators, such as `required`, `min_length`, `max_length`, etc. * **Validation rules**: These define how the input data should be validated. For example, you can use the `required` validator to ensure a field is not empty. * **Form validation models**: These are classes that contain validation rules and behave like models in your application. **Implementing Form Validation** To implement form validation, follow these steps: 1. Load the `Form_validation` library using the following code: ```php require APPPATH . 'libraries/Form_validation.php'; ``` This assumes your application's code is organized like this: ``` app/code app/config app/drivers app ethernet erste app/.exceptions ``` 2. Create a form and add validation fields using the following code: ```php $this->form_validation->set_rules('full_name', 'Full Name', 'required'); $this->form_validation->set_rules('email', 'Email', 'required|valid_email'); ``` This code adds the `full_name` and `email` fields to the form, requiring the user to enter a value for both fields. The `valid_email` validator ensures the email address is in a valid format. 3. Check if the form has been submitted using the following code: ```php if ($this->form_validation->run() == FALSE) { // Display the validation errors $this->load->view('form', $data); } else { // The form has been submitted successfully $this->do_something(); } ``` 4. In your controller, you can access the validated input data using the following code: ```php $data = $this->input->post(); // Use the $data array as needed ``` **Example Code** Here's a complete example of handling forms and user input in CodeIgniter: ```php <?php defined('BASEPATH') OR exit('No direct script access allowed'); class Users extends CI_Controller { public function index() { $this->load->view('form'); } public function submit() { // Load the form_validation library require APPPATH . 'libraries/Form_validation.php'; // Create a form model $this->load->model('users_model'); // Set the validation rules $this->form_validation->set_rules('full_name', 'Full Name', 'required'); $this->form_validation->set_rules('email', 'Email', 'required|valid_email'); // Check if the form has been submitted if ($this->form_validation->run() == FALSE) { // Display the validation errors $data = array('error' => $this->form_validation->error_string()); $this->load->view('form', $data); } else { // The form has been submitted successfully // Get the validated input data $data = $this->input->post(); $this->users_model->insert_user($data); redirect('users/success'); } } } class Users_model extends CI_Model { public function insert_user($data) { // Insert the user into the database $this->db->insert('users', $data); return $this->db->insert_id(); } } ``` **Tasks** 1. Implement a form that collects the user's full name and email address. Use form validation to ensure that both fields are not empty and contain a valid email address. 2. Create a form that collects the year of birth from the user. Use form validation to ensure that the entered year is between 1900 and 2023. 3. Implement a form that accepts different file types for uploading, such as images and documents. 4. Implement a form that automatically populates a certain field based on the user's input. What are some common forms features that are used to process data collected? At the following URL there are additional articles related topics.https://www CodeIgniter.com/userguide3/formvalidation Please let me know if you Have any question related to following Examples. Do leave a comment, and I will respond to it.