A simple CodeIgniter PHP CAPTCHA script

WARNING: This package is no longer being maintained.

This is a fork of Cory LaViska's simple, highly readable PHP captcha: https://github.com/claviska/simple-php-captcha

This is the exact same script, modified to work with the CodeIgniter PHP framework.

Copyright 2011 Cory LaViska for A Beautiful Site, LLC. (http://abeautifulsite.net/)

Dual licensed under the MIT / GPLv2 licenses

Original Demo

http://labs.abeautifulsite.net/simple-php-captcha/

Requirements

• Requires PHP GD library
• Background images must be in PNG format
• Fonts can be either TTF or OTF format

This code was tested with CodeIgniter 2.1.3.

Installation

• Move the controller file to your controllers directory.
• Move the libraries file to your libraries directory.
• Move the entire captcha directory to wherever you keep your assets (images, javascript, css, etc)
• You will need to change the png_backgrounds and fonts settings in the library file to wherever you keep your assets, or simply pass an array with the new configuration when calling $this->captcha->main().

Usage

Place this code in the controller that processes the form:

$this->load->library('captcha');
$data['captcha'] = $this->captcha->main();
$this->session->set_userdata('captcha_info', $data['captcha']);

You can then pass $data['captcha'] to your view and show the captcha image like so:

<img src="<?php echo $captcha['image_src'];?>" alt="CAPTCHA security code" />

To validate the captcha code after the form is submitted, compare the user's input to the captcha_info userdata, in the code value. E.g.:

$captcha_info = $this->session->userdata('captcha_info');
if ($captcha_info['code'] != $this->input->post('captcha'))
{
	//don't process the form
}

Or, you can use the validation function below.

Validation Function

You can use this function in conjunction with the form_validation class. Place this function in the same controller.

/**
 * verifies that the captcha is correct
 * @param  string $str the captcha string
 * @return bool        true on pass, false on failure
 */
public function captcha($str)
{
	$captcha_info = $this->session->userdata('captcha_info');
	if ($captcha_info['code'] != $str)
	{
		$this->form_validation->set_message('captcha', 'The %s was not input correctly. Please try again.');
		return false;
	}

	return true;
}

Add this rule to your form to use the function:

$this->form_validation->set_rules('captcha', 'CAPTCHA', 'trim|required|callback_captcha|xss_clean');