Why Use Codeigniter’s Built-in Captcha

Captchas are the images you use on your forms to keep bots off the bay. Codeigniter gives you a built-in captcha helper which you can use to generate some captchas. Bit confusing part for newbies is using codeigniter’s form validation with built-in captcha. Following is the working example of captcha generation and captcha validation in codeigniter.

Controller

Test.php

[php]
<?php class Test extends CI_Controller { public function my_form(){ if($this->input->post()){
$this->load->library("form_validation");
$this->form_validation->set_rules(‘captcha’, ‘Captcha’, ‘callback_validate_captcha’); // Described below

if ($this->form_validation->run() == FALSE) {
$data[‘captcha’][‘image’] = $this->session->userdata("image");
}
else {
if(!$this->session->has_userdata(‘filename’))
redirect("Test/my_form");

if(file_exists(BASEPATH."../assets/captcha/".$this->session->userdata[‘filename’]))
unlink(BASEPATH."../assets/captcha/".$this->session->userdata[‘filename’]);

session_destroy();
print "So, You are not a robot!";
exit;
}
}
else{
$data[‘captcha’] = $this->_generate_captcha(); // Captcha Generated using custom function defined below
$session_data = array(‘captcha’ => $data[‘captcha’][‘word’],
‘image’ => $data[‘captcha’][‘image’],
‘filename’ => $data[‘captcha’][‘filename’] );

$this->load->library(‘session’);
$this->session->set_userdata($session_data);
}

$this->load->view(‘myform’, $data);
}

function _generate_captcha(){
$this->load->library(‘image_lib’);
$this->load->helper(‘captcha’);

$options = array(
‘img_path’ => ‘./assets/captcha/’, // this directory needs to be created to store generated image
‘img_url’ => base_url("assets/captcha"), // absolute path to directory.
‘img_width’ => 200,
‘expiration’ => 7200,
‘word_length’ => 8,
‘font_size’ => 30,
‘img_id’ => ‘Imageid’,
‘pool’ => ‘0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ’,

‘colors’ => array(
‘background’ => array(255, 255, 255),
‘border’ => array(255, 255, 255),
‘text’ => array(0, 0, 0),
‘grid’ => array(255, 40, 40))
);

$captcha = create_captcha($options);
return $captcha;
}

public function validate_captcha(){
$this->load->library(array("form_validation", "session"));
if(strtolower($this->input->post(‘captcha’)) != strtolower($this->session->userdata[‘captcha’])){
$this->form_validation->set_message(‘validate_captcha’, ‘Wrong captcha code’);
return false;
}
else{
return true;
}

}
}
?>

[/php]

View

myform.php

[html]

<form method="post">
<?php print $captcha[‘image’] ; print form_error(‘captcha’); ?>
<input name="captcha" placeholder="captcha" type="text">
<button type="submit">Validate Captcha</button>
</form>

[/html]

Download the compressed source code from here (mirror).

• Tags:
• codeigniter
• php