CAPTCHA Component

A CAPTCHA (an acronym for "Completely Automated Public Turing test to tell Computers and Humans Apart") is a type of challenge-response test used in computing to determine whether or not the user is human.

Options

The CAPTCHA ships with the following adapter types:

• math adapter. Renders a simply arithmetic expression, like 2 + 3.
• number adapter. Renders a random number
• fixed adapter. Renders test message
• randomadapter. Renders randomly generated text

These options must be defined in options section as a value of the text key.

There are also several options that define the looks. Here they are:

• width. Defines a width of an image to be generated. If omitted then 120 used as a default value.
• height. Defines a width of an image to be generated. If omitted then 50 used as a default value.
• padding. The padding offset. If omitted then 3 used as a default value.
• transparent. Defines whether generated image should be transparent or not. If omitted, then false used as a default value.
• background_color. Defines a background color for the CAPTCHA image. If omitted, then 0xFFFFFF (white) used as a default value.
• text_color. Defines a text color of the CAPTCHA symbols. If omitted, then 0x3440A0 (blue) used as a default value.
• font. The basename of font file. You can use any one of: Windsong.ttf, Walkway_Bold.ttf, Pacifico.ttf, Duality.ttf, Arimo.ttf. If omitted, then Arimo.ttf used as a default value.

Example: Using with the framework

The CAPTCHA is not activated by default. In order to activate it, you should enable the service in configuration array.

Step 1: Register a service in a configuration file

First of all, open /config/app.php and add this definition:

'components' => array(
    //...

    // Add this:
    'captcha' => array(
        // The type
        'type' => 'standard',
        // Options for provided type
        'options' => array(
            'text' => 'math'
            // Aforementioned options (such as width, height) can be optionally set here
        )
    ),

    //....

Done. Now the framework knows about this service.

Step 2: Render the CAPTCHA!

Before you render the CAPTCHA, you need to declare a route that responses as a rendered CAPTCHA image. So, you can simply attach a new route in your module.

return array(

    //..

    '/site/captcha' => array(
        'controller' => 'YourModule@renderAction'
    ),

    // ...
)

Now you have a service which is called captchaand you can access it in controllers, just like another services. All you have to do is to simply render an image. For example:

<?php

namespace YourModule\Controller;

use Krystal\Application\Controller\AbstractController;

class Captcha extends AbstractController
{
     public function renderAction()
     {
          $this->captcha->render();
     }
}

Then in templates you can render an image, like this:

<img src="<?php echo $this->url('YourModule@renderAction'); ?>" />

Step 3: Validate entered answer

To validate an answer, you simply need to attach the CAPTCHA's service to validation rules.

  'definition' => array(
      'email' => new Pattern\Email(),
      'captcha' => new Pattern\Captcha($this->captcha)
  )

Where captcha and email are POST keys. If you're not sure how to use validation and patterns, please refer to its documentation.

Example: Using as a standalone component

In case you want to use this component as a standalone library without the framework itself, you can do it like this:

<?php

// Include Composer's autoloader
require('vendor/autoload.php');

// Now simply, instantiate a captcha
$captcha = \Krystal\Captcha\Standard\CaptchaFactory::build(array(
    // Additional options can be set here
    'text' => 'math'
));


// Done! You're ready!
if (isset($_GET['render'])) {

    $captcha->render();
    exit;
}

// Checking is answer is valid
if (isset($_POST['answer']) && $captcha->isValid($_POST['answer'])) {

    echo 'Valid answer!';
    $captcha->clear();

} else {

    echo $captcha->getError();
}

?>

<form method="POST">

    <img src="<?php echo $_SERVER['REQUEST_URI'];?>?render=1" />

    <br />

    <input type="text" name="answer" />

    <button type="submit">Verify</button>

</form>