CodeIgniter CAPTCHA Helper

A CAPTCHA (Complete Automated Public Turning test to tell Computer and Humans Apart) helper is a function that is used in web application to check whether the user is human or machine. It provides a randomly generated string to identify the user. In this way, it protects the web application from various spams.

A CAPTCHA is an important part of a web application, where the action is processed based on the user’s inputs or responses.

A CAPTCHA helper file has some predefined function that is used to create CAPTCHA images.

• Loading the helper

It is used to load the helper class and passes the helper function in the controller’s method.

Syntax: - $this->load->helper(‘captcha’);

Configuration of CAPTCHA helper

• img_path: It defines the path where all the CAPTCHA images are stored.
• img_url: It defines the URL, where the CAPTCHA images are shown.
• img_width: It represents the width of the CAPTCHA image. By default, it is 150.
• img_height: It represents the height of the CAPTCHA image. By default, it is 30.
• word_length: It is optional. You can define it or leave it. By default, it is 8.
• font_size: It is also optional. It defines the size of the CAPTCHA word. The default font size is 16.
• font_path (optional): It defines the path where the font directory is stored.
• expiration (in seconds): It shows that for how long the picture can be stored in the CAPTCHA folder before it gets deleted. By default, it remains in the folder for 2 hours.
• pool: It is an optional feature. It is used in the CAPTCHA to specify the type of letters you want to use. By default, it uses ‘0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ’;

Example of Predefined data in CAPTCHA Helper:

Before loading the CAPTCHA helper in Controller, you need to create a folder in CodeIgniter application where you can save your CAPTCHA images.

In the following image, we have created a folder named captcha_images.

Example: Create a Tests.php file in application/controller folder and write the following program:

Tests.php

<?php
 class Tests extends CI_Controller {
  public function index()
 {
      echo "<title> Welcome To Tutorials And Examples </title>"; 
     $this->load->helper('CAPTCHA'); // load the captcha helper
     $info = array ( 
      'word' => "AMIT YADAV",  // Predefined names
         'img_path'      => 'captcha_images/',
         'img_url'       => base_url().'captcha_images/', 
         'font_path'  => 'system/fonts/texb.ttf',
         'img_width'     => '250',
         'img_height'    => '70',
         'word_length'   => '10',
         'font_size'     => '20',
         'colors'        => array (          // White background and border, black text and red grid
           'background' => array (100, 125, 255),
           'border' => array (255, 100, 255), 
           'text' => array (2, 7, 0),
           'grid' => array (125, 40, 40)
   )     
 ); 
 echo "<h2>Captcha Images: Predefined Data </h2>"; 
 $captcha = create_captcha($info);
 echo $cap['image'];
 }
 } 
 ?> 

Let’s execute the above program by invoking the URL localhost/CodeIgniter-3.1.11/index.php/test/. It shows the output, as shown below.

Example of Random generated images in CAPTCHA Helper:

As the name suggests, random CAPTCHA images are generated in this web application. Now create a Tests.php file in application/controller folder and write the following program:

Tests.php

<?php
 class Tests extends CI_Controller {
  public function index(){
      echo "<title> Welcome To Tutorials And Examples </title>"; 
     $this->load->helper('CAPTCHA');
     $vals = array (
         'img_path'      => 'CAPTCHA_images/',
         'img_url'       => base_url().'CAPTCHA_images/', 
         'font_path'  => 'system/fonts/texb.ttf',
         'img_width'     => '250',
         'img_height'    => '70',
         'word_length'   => '10',
         'font_size'     => '20', 
         'pool'          => '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ',
         'colors'        => array (     // it is used to change the background color, border, text
           'background' => array (100, 125, 255),
           'border' => array (255, 100, 255),
           'text' => array (2, 7, 0), 
           'grid' => array (125, 40, 40)
   )
 ); 
 echo "<h2>Captcha Images: Predefined Data </h2>"; 
 $CAPTCHA = create_CAPTCHA($info);
 echo $cap['image'];
 }
 }
 ?> 

Let’s execute the above program by invoking the URL localhost/CodeIgniter-3.1.11/index.php/test/. It shows the output, as shown below.

When we refresh the page, it produces a new CAPTCHA image, as shown in the following image.