File controllers/components/captcha.php | BEdita API doc

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<?php
/*-----8<--------------------------------------------------------------------
 * 
 * BEdita - a semantic content management framework
 * 
 * Copyright 2008 ChannelWeb Srl, Chialab Srl
 * 
 * This file is part of BEdita: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published 
 * by the Free Software Foundation, either version 3 of the License, or 
 * (at your option) any later version.
 * BEdita is distributed WITHOUT ANY WARRANTY; without even the implied 
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU Lesser General Public License for more details.
 * You should have received a copy of the GNU Lesser General Public License 
 * version 3 along with BEdita (see LICENSE.LGPL).
 * If not, see <http://gnu.org/licenses/lgpl-3.0.html>.
 * 
 *------------------------------------------------------------------->8-----
 */

/**
 * Captcha creation and management
 *
 * @version         $Revision$
 * @modifiedby      $LastChangedBy$
 * @lastmodified    $LastChangedDate$
 * 
 * $Id$
 */
class CaptchaComponent extends Object {
    
    var $controller;
    private $fontColor = array("red" => 193, "green" => 0, "blue" => 118);
    private $background;
    private $fontType;
    
    function startup(&$controller) {
        $this->controller = &$controller;
        // set default
        $this->background = BEDITA_CORE_PATH . DS . "webroot".DS."captcha".DS."img".DS."button.png";
        $this->fontType = BEDITA_CORE_PATH . DS . "webroot".DS."captcha".DS."fonts".DS."Vera.ttf";
    }

    /**
     * output a PNG image captcha
     * 
     * @param array $options
     */
    public function image($options=array()) {
        $length = (!empty($options["length"]))? $options["length"] : 4;
        if (!empty($options["color"]))
            $this->fontColor = $options["color"];
         
        // Create a random string, leaving out 'o' to avoid confusion with '0'
        $str = strtoupper(substr(str_shuffle('123456789abcdefghjkmnpqrstuvwxyz'), 0, $length));
        
        // put captcha id in session
        $this->controller->Session->write("captcha_id", $str);
        
        // send several headers to make sure the image is not cached
        // taken directly from the PHP Manual

        // Expire in the past, always modified
        header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
        header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT"); 
        // HTTP/1.1
        header("Cache-Control: no-store, no-cache, must-revalidate");
        header("Cache-Control: post-check=0, pre-check=0", false); 
        // HTTP/1.0
        header('Pragma: no-cache');
        //content type
        header('Content-type: image/png'); 
                    
        // Create a background image
        if (is_dir(APP . "webroot".DS."captcha".DS."img")) {
            foreach (glob(APP . "webroot".DS."captcha".DS."img".DS."*.png") as $filename) {
                $bgArr[] = $filename;
            }
        } else {
            foreach (glob(BEDITA_CORE_PATH . "webroot".DS."captcha".DS."img".DS."*.png") as $filename) {
                $bgArr[] = $filename;
            }
        }
        
        if (!empty($bgArr))
            $this->background = $bgArr[array_rand($bgArr)];
        
        $image = imagecreatefrompng($this->background);
        
        // Set the font colour
        $colour = imagecolorallocate($image, $this->fontColor["red"], $this->fontColor["green"], $this->fontColor["blue"]);
        
        // Set the font
        if (is_dir(APP . "webroot".DS."captcha".DS."fonts")) {
            foreach (glob(APP . "webroot".DS."captcha".DS."fonts".DS."*.ttf") as $filename) {
                $fontArr[] = $filename;
            }
        } else {
            foreach (glob(BEDITA_CORE_PATH . "webroot".DS."captcha".DS."fonts".DS."*.ttf") as $filename) {
                $fontArr[] = $filename;
            }
        }
        
        if (!empty($fontArr))
            $this->fontType = $fontArr[array_rand($fontArr)];
        
        // get image size
        $imgsize = getimagesize($this->background);
        $width = $imgsize[0];
        $height = $imgsize[1];
        $charSpace = $width / (strlen($str)+1);
        
        // Create an image using our original image and adding the detail
        for ($i=0; $i< strlen($str); $i++)  {
            imagettftext($image, 14+mt_rand(0,8), -20+mt_rand(0,40), ($i+0.3)*$charSpace, ($height/2)+mt_rand(0,10), $colour, $this->fontType, $str{$i});
        }
        
        // Output the image as a png
        imagepng($image);
    }

    /**
     * Check captcha form data
     * 
     * @return boolean
     * @throws BeditaException
     */
    public function checkCaptcha() {
        if (empty($this->controller->params["form"]["captcha"]))
            throw new BeditaException(__("Captcha image and text don't match", true));
        $captcha = $this->controller->params["form"]["captcha"];
        if( $this->controller->Session->valid() && (strtoupper($captcha) == $this->controller->Session->read('captcha_id')) )
            return true;
        else
            throw new BeditaException(__("Text doesn't match image", true));
    }

    /**
     * Set font color
     * 
     * @param string $red
     * @param string $green
     * @param string $blue
     */
    public function setFontColor($red, $green, $blue) {
        $this->fontColor = array("red" => $red, "green" => $green, "blue" => $blue);
    }
    
}

?>

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