/protected/extensions/captchaExtended/CaptchaExtendedAction.php

<?php

/**

* Yii extended captcha supporting more complex formulas and masking techniques.

* 

* Features:

*    - supported modes: logical, words, mathverbal, math, default

*    - supported extended characters latin1, latin2 (utf-8) including middle- east- european and cyrillyc characters

*    - implements masking elements: dots density, through lines, fillSections, font color varying

* 

* Installation:

* =============

* 

* 	  1) unzip CaptchaExtended.zip files into ../protected/extensions/captchaExtended/*.*

* 

*     2) Register class paths to [CaptchaExtendedAction] and [CaptchaExtendedValidator], e.g. in components/controller.php:

* 

*			public function init(){

*				// import class paths for captcha extended

*				Yii::$classMap = array_merge( Yii::$classMap, array(

*					'CaptchaExtendedAction' => Yii::getPathOfAlias('ext.captchaExtended').DIRECTORY_SEPARATOR.'CaptchaExtendedAction.php',

*					'CaptchaExtendedValidator' => Yii::getPathOfAlias('ext.captchaExtended').DIRECTORY_SEPARATOR.'CaptchaExtendedValidator.php'

*				));

*			}

*

* 	  3) Define action in controller, e.g. SiteController:

* 

*			public function actions(){

*				return array(

*					'captcha'=>array(

*						'class'=>'CaptchaExtendedAction',

*					),

*				);

*			}

*

* 	  4) Define client validation in model::rules():

* 

*			public function rules(){

*				return array(

*					array('verifyCode', 'CaptchaExtendedValidator', 'allowEmpty'=>!CCaptcha::checkRequirements()),

*				);

*			}

* 

* 	   5) If needed, collect localized strings via CLI command "yiic message messages/config.php" and translate captcha related strings.

* 

* 	   6) If needed, you can tune captcha modes and visibility options: 

* 		  - In "words" mode, you can place your own file [words.txt] or [words.yourlanguage.txt]

* 		  - If needed, set the dots density [0-100], the number of through lines [0-] or fillSections [0-], font and background colors

* 

* 	   7) Test & enjoy!

*/

class CaptchaExtendedAction extends CCaptchaAction{

	

	const

		MODE_MATH = 'math',

		MODE_MATHVERBAL	= 'mathverbal',

		MODE_DEFAULT = 'default',

		MODE_LOGICAL = 'logical',

		MODE_WORDS = 'words';



	/**

	 * @var integer padding around the text. Defaults to 2.

	 */

	public $offset = 2;

	

	/**

	* Captcha mode, supported values are [logical, words, mathverbal, math, default].

	* Default value is [default], which uses native frameworks implementation.

	* Captcha mode examples:

	*  - logical e.g. min(5, one, 9) or max (two, three, 3)

	*  - words e.g. [localized random words] (supports translated strings in UTF-8 including latin2 and cyrillic)

	*  - mathverbal e.g. How much is 12 plus 8 ?

	*  - math e.g. 93 - 3 =

	*  - default e.g. random latin1 characters

	*/

	public $mode = self::MODE_MATH;



	/**

	* Path to the file to be used for generating random words in "words" mode

	*/

	public $fileWords;



	/**

	* Dots density around characters 0 - 100 [%], defaults 5.

	*/

	public $density = 5; // dots density 0 - 100%

	

	/**

	* The number of lines drawn through the generated captcha picture, default 3.

	*/

	public $lines = 3;

	

	/**

	* The number of sections to be filled with random flood color, default 10.

	*/

	public $fillSections = 10;

	

	/**

	* Run action

	*/

	public function run(){

		

		if(!extension_loaded('mbstring')){

			throw new CHttpException(500, Yii::t('main','Missing extension "{ext}"', array('{ext}' => 'mbstring')));

		}



		// set font file with all extended UTF-8 characters

		// Duality supplied with the framework does not support some extended characters like ščťžôäě...

		$this->fontFile = dirname(__FILE__).'/fonts/nimbus.ttf';

		

		// set captcha mode

		$this->mode = strtolower($this->mode);

		

		// set image size

		switch ($this->mode){

			case self::MODE_LOGICAL:

			case self::MODE_WORDS:

				$this->width = 300;

				$this->height = 50;

				break;

			case self::MODE_MATHVERBAL:

				$this->width = 400;

				$this->height = 50;

				break;

			case self::MODE_MATH:

			case self::MODE_DEFAULT:

			default:

				$this->width = 120;

				$this->height = 50;

		}

		

		if($this->mode == self::MODE_DEFAULT){

			// default framework implementation

			parent::run();

		}else{

			// we hash result value rather than the displayed code

			if(isset($_GET[self::REFRESH_GET_VAR])){

				$result=$this->getVerifyResult(true);

				echo CJSON::encode(array(

					'hash1'=>$this->generateValidationHash($result),

					'hash2'=>$this->generateValidationHashCI($result),

					'url'=>$this->getController()->createUrl($this->getId(),array('v' => uniqid())),

				));

			}else{

				$this->renderImage($this->getVerifyCode());

			}

		}

		Yii::app()->end();

	}

	

	/**

	* Return hash for case insensitive result (converted to lowercase)

	* @param string $result

	*/

	protected function generateValidationHashCI($result){

		$result = preg_replace('/\s/', '', $result);

		$result = mb_convert_case($result, MB_CASE_LOWER, 'utf-8');

		$result = urlencode($result);

		return $this->generateValidationHash($result);

	}

	

	/**

	 * Generates a new verification code.

	 * @return string the generated verification code

	 */

	protected function generateVerifyCode(){

		switch (strtolower($this->mode)){

			case self::MODE_MATH:

				return $this->getCodeMath();

			case self::MODE_MATHVERBAL:

				return $this->getCodeMathVerbal();

			case self::MODE_LOGICAL:

				return $this->getCodeLogical();

			case self::MODE_WORDS:

				return $this->getCodeWords();

			case self::MODE_DEFAULT:

			default:

				$code = parent::generateVerifyCode();

				return array('code' => $code, 'result' => $code);

		}

	}

	

	/**

	* Return code for random words from text file.

	* First we'll try to load file for current language, like [words.de.txt]

	* If not found, we will try to load generic file like [words.txt]

	*/

	protected function getCodeWords(){

		if($this->fileWords === null){

			// guess words file upon current language like [words.de.txt], [words.ru.txt]

			$this->fileWords = dirname(__FILE__).DIRECTORY_SEPARATOR.'words.'.Yii::app()->language.'.txt';

			if(!is_file($this->fileWords)){

				// take fallback file without language specification

				$this->fileWords = dirname(__FILE__).DIRECTORY_SEPARATOR.'words.txt';

			}

		}

		if(!file_exists($this->fileWords)){

			throw new CHttpException(500, Yii::t('main','FIle not found in "{path}"', array('{path}' => $this->fileWords)));

		}

		$words = file_get_contents($this->fileWords);

		$words = explode(' ', $words);

		$found = array();

		for($i=0;$i<count($words);++$i){

			// select random word

			$w = array_splice($words, mt_rand(0,count($words)),1);

			if(!isset($w[0])){

				continue;

			}

			// purify word

			$w = $this->purifyWord($w[0]);

			if(strlen($w)>3){

				// accept only word with at least 3 characters

				$found[] = $w;

				if(strlen(implode('', $found))>10){

					// words must have at least 10 characters together

					break;

				}

			}

		}

		$code = implode('', $found); // without whitespaces

		return array('code' => $code, 'result' => $code);

	}

	

	/**

	* Return captcha word without dirty characters like *,/,{,},.. Retain diacritics if unicode supported.

	* @param string $w The word to be purified

	*/

	protected function purifyWord($w){

		if(@preg_match('/\pL/u', 'a')){

			// unicode supported, we remove everything except for accented characters

			$w = preg_replace('/[^\p{L}]/u', '', (string) $w);

		}else{

			// Unicode is not supported. Cannot validate utf-8 characters, we keep only latin1

			$w = preg_replace('/[^a-zA-Z0-9]/','',$w);

		}

		return $w;

	}

	

	/**

	* Return code for math mode like 9+1= or 95-5=

	*/

	protected function getCodeMath(){

		$n2 = mt_rand(1,9);

		if(mt_rand(1,100) > 50){

			$n1 = mt_rand(1,9)*10+$n2;

			$code = $n1.'-'.$n2.'=';

			$r = $n1-$n2;

		}else{

			$n1 = mt_rand(1,10)*10-$n2;

			$code = $n1.'+'.$n2.'=';

			$r = $n1+$n2;

		}

		return array('code' => $code, 'result' => $r);

	}

	

	/**

	* Return numbers 0..9 translated into word

	*/

	protected static function getNumbers(){

		return array(

			'0' => Yii::t('main','zero'),

			'1' => Yii::t('main','one'),

			'2' => Yii::t('main','two'),

			'3' => Yii::t('main','three'),

			'4' => Yii::t('main','four'),

			'5' => Yii::t('main','five'),

			'6' => Yii::t('main','six'),

			'7' => Yii::t('main','seven'),

			'8' => Yii::t('main','eight'),

			'9' => Yii::t('main','nine'),

		);

	}

	

	/**

	* Return verbal representation for supplied number, like 1 => one

	* @param int $n The number to be translated

	*/

	protected static function getNumber($n){

		static $nums;

		if(empty($nums)){

			$nums = self::getNumbers();

		}

		return array_key_exists($n, $nums) ? $nums[$n] : '';

	}

	

	/**

	* Return code for logical formula like min(one,7,four)

	*/

	protected function getCodeLogical(){

		$t = mt_rand(2,4);

		$a = array();

		for($i=0;$i<$t;++$i){

			// we dont use zero

			$a[] = mt_rand(1,9);

		}

		if(mt_rand(0,1)){

			$r = max($a);

			$code = array();

			for($i=0;$i<count($a);++$i){

				$code[] = mt_rand(1,100)>30 ? self::getNumber($a[$i]) : $a[$i];

			}

			$code = Yii::t('main','max').' ( '.implode(', ',$code).' )';

		}else{

			$r = min($a);

			$code = array();

			for($i=0;$i<count($a);++$i){

				$code[] = mt_rand(1,100)>30 ? self::getNumber($a[$i]) : $a[$i];

			}

			$code = Yii::t('main','min').' ( '.implode(', ',$code).' )';

		}

		return array('code' => $code, 'result' => $r);

	}

	

	/**

	* Return code for verbal math mode like "How much is 1 plus 1 ?"

	*/

	protected function getCodeMathVerbal(){

		$n2 = mt_rand(1,9);

		if(mt_rand(1,100) > 50){

			switch(mt_rand(0,2)){

				case 0:

					$op = Yii::t('main','minus');

					break;

				case 1:

					$op = Yii::t('main','deducted by');

					break;

				case 2:

					$op = '-';

					break;

			}

			$n1 = mt_rand(1,9)*10+$n2;

			$code = $n1.' '.$op.' '. ( mt_rand(1,10)>3 ? self::getNumber($n2) : $n2);

			$r = $n1-$n2;

		}else{

			switch(mt_rand(0,2)){

				case 0:

					$op = Yii::t('main','plus');

					break;

				case 1:

					$op = Yii::t('main','and');

					break;

				case 2:

					$op = '+';

					break;

			}

			$n1 = mt_rand(1,10)*10-$n2;

			$code = $n1.' '.$op.' '.( mt_rand(1,10)>3 ? self::getNumber($n2) : $n2);

			$r = $n1+$n2;

		}

		switch (mt_rand(0,2)){

			case 0:

				$question = Yii::t('main','How much is');

				break;

			case 1:

				$question = Yii::t('main','What\'s result for');

				break;

			case 2:

				$question = Yii::t('main','Give result for');

				break;

		}



		switch (mt_rand(0,2)){

			case 0:

				$equal = '?';

				break;

			case 1:

				$equal = '=';

				break;

			case 2:

				$equal = str_repeat('.', mt_rand(2,5));

				break;

		}



		$code = $question.' '.$code.' '.$equal;

		return array('code' => $code, 'result' => $r);

	}	

	

	

	/**

	 * 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 whether the input is valid

	 */

	public function validate($input,$caseSensitive){

		// open session, if necessary generate new code

		$this->getVerifyCode();

		// read result

		$session = Yii::app()->session;

		$name = $this->getSessionKey();

		$result = $session[$name . 'result'];

		// input always taken without whitespaces

		$input = preg_replace('/\s/','',$input);

		$valid = $caseSensitive ? strcmp($input, $result)===0 : strcasecmp($input, $result)===0;

		// increase attempts counter

		$name = $this->getSessionKey() . 'count';

		$session[$name] = $session[$name] + 1;

		if($valid || $session[$name] > $this->testLimit && $this->testLimit > 0){

			// generate new code also each time correctly entered

			$this->getVerifyCode(true);

		}

		return $valid;

	}

	

	/**

	 * 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(empty($session[$name]) || $regenerate){

			$code = $this->generateVerifyCode();

			$session[$name] = $code['code'];

			$session[$name . 'result'] = $code['result'];

			$session[$name . 'count'] = 1;

		}

		return $session[$name];

	}

	

	/**

	* Return verification result expected by user

	* @param bool $regenerate

	*/

	public function getVerifyResult($regenerate=false){

		if($this->fixedVerifyCode !== null){

			return $this->fixedVerifyCode;

		}

		$session = Yii::app()->session;

		$session->open();

		$name = $this->getSessionKey();

		if(empty($session[$name . 'result']) || $regenerate){

			$code = $this->generateVerifyCode();

			$session[$name] = $code['code'];

			$session[$name . 'result'] = $code['result'];

			$session[$name . 'count'] = 1;

		}

		return $session[$name . 'result'];

	}

	

	/**

	 * 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);

		}



		if($this->fontFile === null){

			$this->fontFile = dirname(__FILE__) . '/Duality.ttf';

		}



		$length = strlen($code);

		$box = imagettfbbox(25,0,$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);

		

		$r = (int)($this->foreColor % 0x1000000 / 0x10000);

		$g = (int)($this->foreColor % 0x10000 / 0x100);

		$b = $this->foreColor % 0x100;

		$foreColor = imagecolorallocate($image, mt_rand($r-50,$r+50), mt_rand($g-50,$g+50),mt_rand($b-50,$b+50));

		

		for($i = 0; $i < $length; ++$i){

			$fontSize = (int)(rand(26,32) * $scale * 0.8);

			$angle = rand(-10,10);

			$letter = $code[$i];

			

			// UTF-8 characters above > 127 are stored in two bytes

			if(ord($letter)>127){

				++$i;

				$letter .= $code[$i];

			}

			

			// randomize font color

			if(mt_rand(0,10)>7){

				$foreColor = imagecolorallocate($image, mt_rand($r-50,$r+50), mt_rand($g-50,$g+50),mt_rand($b-50,$b+50));

			}

			

			$box = imagettftext($image,$fontSize,$angle,$x,$y,$foreColor,$this->fontFile,$letter);

			$x = $box[2] + $this->offset;

		}

		

		// add density dots

		$this->density = intval($this->density);

		if($this->density > 0){

			$length = intval($this->width*$this->height/100*$this->density);

			$c = imagecolorallocate($image, mt_rand(0,255), mt_rand(0,255), mt_rand(0,255)); 

			for($i=0;$i<$length;++$i){

				$x = mt_rand(0,$this->width);

				$y = mt_rand(0,$this->height);

				imagesetpixel($image, $x, $y, $c);

			}

		}

		

		// add lines

		$this->lines = intval($this->lines);

		if($this->lines > 0){

			for($i=0; $i<$this->lines; ++$i){

				imagesetthickness($image, mt_rand(1,2));

				// gray lines only to save human eyes:-)

				$c = imagecolorallocate($image, mt_rand(200,255), mt_rand(200,255), mt_rand(200,255));

				$x = mt_rand(0, $this->width);

				$y = mt_rand(0, $this->width);

				imageline($image, $x, 0, $y, $this->height, $c);

			}

		}

		

		// filled flood section

		$this->fillSections = intval($this->fillSections);

		if($this->fillSections > 0){

			for($i = 0; $i < $this->fillSections; ++$i){

				$c = imagecolorallocate($image, mt_rand(200,255), mt_rand(200,255), mt_rand(200,255));

				$x = mt_rand(0, $this->width);

				$y = mt_rand(0, $this->width);

				imagefill($image, $x, $y, $c);

			}

		}



		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);

	}

	

}