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<?php
/**
* CCaptchaAction class file.
*
* @author Qiang Xue <qiang.xue@gmail.com>
* @link http://www.yiiframework.com/
* @copyright Copyright &copy; 2008-2011 Yii Software LLC
* @license http://www.yiiframework.com/license/
*/
/**
* CCaptchaAction renders a CAPTCHA image.
*
* CCaptchaAction is used together with {@link CCaptcha} and {@link CCaptchaValidator}
* to provide the {@link http://en.wikipedia.org/wiki/Captcha CAPTCHA} feature.
*
* You must configure properties of CCaptchaAction to customize the appearance of
* the generated image.
*
* Note, CCaptchaAction requires PHP GD2 extension.
*
* Using CAPTCHA involves the following steps:
* <ol>
* <li>Override {@link CController::actions()} and register an action of class CCaptchaAction with ID 'captcha'.</li>
* <li>In the form model, declare an attribute to store user-entered verification code, and declare the attribute
* to be validated by the 'captcha' validator.</li>
* <li>In the controller view, insert a {@link CCaptcha} widget in the form.</li>
* </ol>
*
* @property string $verifyCode The verification code.
*
* @author Qiang Xue <qiang.xue@gmail.com>
* @version $Id$
* @package system.web.widgets.captcha
* @since 1.0
*/
class CCaptchaAction extends CAction
{
/**
* The name of the GET parameter indicating whether the CAPTCHA image should be regenerated.
*/
const REFRESH_GET_VAR='refresh';
/**
* Prefix to the session variable name used by the action.
*/
const SESSION_VAR_PREFIX='Yii.CCaptchaAction.';
/**
* @var integer how many times should the same CAPTCHA be displayed. Defaults to 3.
* A value less than or equal to 0 means the test is unlimited (available since version 1.1.2).
*/
public $testLimit = 3;
/**
* @var integer the width of the generated CAPTCHA image. Defaults to 120.
*/
public $width = 120;
/**
* @var integer the height of the generated CAPTCHA image. Defaults to 50.
*/
public $height = 50;
/**
* @var integer padding around the text. Defaults to 2.
*/
public $padding = 2;
/**
* @var integer the background color. For example, 0x55FF00.
* Defaults to 0xFFFFFF, meaning white color.
*/
public $backColor = 0xFFFFFF;
/**
* @var integer the font color. For example, 0x55FF00. Defaults to 0x2040A0 (blue color).
*/
public $foreColor = 0x2040A0;
/**
* @var boolean whether to use transparent background. Defaults to false.
*/
public $transparent = false;
/**
* @var integer the minimum length for randomly generated word. Defaults to 6.
*/
public $minLength = 6;
/**
* @var integer the maximum length for randomly generated word. Defaults to 7.
*/
public $maxLength = 7;
/**
* @var integer the offset between characters. Defaults to -2. You can adjust this property
* in order to decrease or increase the readability of the captcha.
* @since 1.1.7
**/
public $offset = -2;
/**
* @var string the TrueType font file. Defaults to Duality.ttf which is provided
* with the Yii release.
*/
public $fontFile;
/**
* @var string the fixed verification code. When this is property is set,
* {@link getVerifyCode} will always return this value.
* This is mainly used in automated tests where we want to be able to reproduce
* the same verification code each time we run the tests.
* Defaults to null, meaning the verification code will be randomly generated.
* @since 1.1.4
*/
public $fixedVerifyCode;
/**
* Runs the action.
*/
public function run()
{
if(isset($_GET[self::REFRESH_GET_VAR])) // AJAX request for regenerating code
{
$code=$this->getVerifyCode(true);
echo CJSON::encode(array(
'hash1'=>$this->generateValidationHash($code),
'hash2'=>$this->generateValidationHash(strtolower($code)),
// we add a random 'v' parameter so that FireFox can refresh the image
// when src attribute of image tag is changed
'url'=>$this->getController()->createUrl($this->getId(),array('v' => uniqid())),
));
}
else
$this->renderImage($this->getVerifyCode());
Yii::app()->end();
}
/**
* Generates a hash code that can be used for client side validation.
* @param string $code the CAPTCHA code
* @return string a hash code generated from the CAPTCHA code
* @since 1.1.7
*/
public function generateValidationHash($code)
{
for($h=0,$i=strlen($code)-1;$i>=0;--$i)
$h+=ord($code[$i]);
return $h;
}
/**
* Gets the verification code.
* @param boolean $regenerate whether the verification code should be regenerated.
* @return string the verification code.
*/
public function getVerifyCode($regenerate=false)
{
if($this->fixedVerifyCode !== null)
return $this->fixedVerifyCode;
$session = Yii::app()->session;
$session->open();
$name = $this->getSessionKey();
if($session[$name] === null || $regenerate)
{
$session[$name] = $this->generateVerifyCode();
$session[$name . 'count'] = 1;
}
return $session[$name];
}
/**
* Validates the input to see if it matches the generated code.
* @param string $input user input
* @param boolean $caseSensitive whether the comparison should be case-sensitive
* @return boolean whether the input is valid
*/
public function validate($input,$caseSensitive)
{
$code = $this->getVerifyCode();
$valid = $caseSensitive ? ($input === $code) : !strcasecmp($input,$code);
$session = Yii::app()->session;
$session->open();
$name = $this->getSessionKey() . 'count';
$session[$name] = $session[$name] + 1;
if($session[$name] > $this->testLimit && $this->testLimit > 0)
$this->getVerifyCode(true);
return $valid;
}
/**
* Generates a new verification code.
* @return string the generated verification code
*/
protected function generateVerifyCode()
{
if($this->minLength < 3)
$this->minLength = 3;
if($this->maxLength > 20)
$this->maxLength = 20;
if($this->minLength > $this->maxLength)
$this->maxLength = $this->minLength;
$length = mt_rand($this->minLength,$this->maxLength);
$letters = 'bcdfghjklmnpqrstvwxyz';
$vowels = 'aeiou';
$code = '';
for($i = 0; $i < $length; ++$i)
{
if($i % 2 && mt_rand(0,10) > 2 || !($i % 2) && mt_rand(0,10) > 9)
$code.=$vowels[mt_rand(0,4)];
else
$code.=$letters[mt_rand(0,20)];
}
return $code;
}
/**
* Returns the session variable name used to store verification code.
* @return string the session variable name
*/
protected function getSessionKey()
{
return self::SESSION_VAR_PREFIX . Yii::app()->getId() . '.' . $this->getController()->getUniqueId() . '.' . $this->getId();
}
/**
* Renders the CAPTCHA image based on the code.
* @param string $code the verification code
* @return string image content
*/
protected function renderImage($code)
{
$image = imagecreatetruecolor($this->width,$this->height);
$backColor = imagecolorallocate($image,
(int)($this->backColor % 0x1000000 / 0x10000),
(int)($this->backColor % 0x10000 / 0x100),
$this->backColor % 0x100);
imagefilledrectangle($image,0,0,$this->width,$this->height,$backColor);
imagecolordeallocate($image,$backColor);
if($this->transparent)
imagecolortransparent($image,$backColor);
$foreColor = imagecolorallocate($image,
(int)($this->foreColor % 0x1000000 / 0x10000),
(int)($this->foreColor % 0x10000 / 0x100),
$this->foreColor % 0x100);
if($this->fontFile === null)
$this->fontFile = dirname(__FILE__) . '/Duality.ttf';
$length = strlen($code);
$box = imagettfbbox(30,0,$this->fontFile,$code);
$w = $box[4] - $box[0] + $this->offset * ($length - 1);
$h = $box[1] - $box[5];
$scale = min(($this->width - $this->padding * 2) / $w,($this->height - $this->padding * 2) / $h);
$x = 10;
$y = round($this->height * 27 / 40);
for($i = 0; $i < $length; ++$i)
{
$fontSize = (int)(rand(26,32) * $scale * 0.8);
$angle = rand(-10,10);
$letter = $code[$i];
$box = imagettftext($image,$fontSize,$angle,$x,$y,$foreColor,$this->fontFile,$letter);
$x = $box[2] + $this->offset;
}
imagecolordeallocate($image,$foreColor);
header('Pragma: public');
header('Expires: 0');
header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
header('Content-Transfer-Encoding: binary');
header("Content-type: image/png");
imagepng($image);
imagedestroy($image);
}
}
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