*/ // must be run within Dokuwiki if(!defined('DOKU_INC')) die(); if(!defined('DOKU_PLUGIN')) define('DOKU_PLUGIN',DOKU_INC.'lib/plugins/'); require_once(DOKU_INC.'inc/blowfish.php'); class helper_plugin_captcha extends DokuWiki_Plugin { /** * Check if the CAPTCHA should be used. Always check this before using the methods below. * * @return bool true when the CAPTCHA should be used */ function isEnabled(){ if(!$this->getConf('forusers') && $_SERVER['REMOTE_USER']) return false; return true; } /** * Returns the HTML to display the CAPTCHA with the chosen method */ function getHTML(){ global $ID; $rand = (float) (rand(0,10000))/10000; $code = $this->_generateCAPTCHA($this->_fixedIdent(),$rand); $secret = PMA_blowfish_encrypt($rand,auth_cookiesalt()); $out = ''; $out .= '
'; $out .= ''; $out .= ' '; $out .= ' '; switch($this->getConf('mode')){ case 'text': $out .= $code; break; case 'js': $out .= ''.$code.''; break; case 'image': $out .= ' '; break; case 'audio': $out .= ' '; $out .= ''; $out .= ''.$this->getLang('soundlink').''; break; case 'figlet': require_once(dirname(__FILE__).'/figlet.php'); $figlet = new phpFiglet(); if($figlet->loadfont(dirname(__FILE__).'/figlet.flf')){ $out .= '
';
                    $out .= rtrim($figlet->fetch($code));
                    $out .= '
'; }else{ msg('Failed to load figlet.flf font file. CAPTCHA broken',-1); } break; } $out .= '
'; return $out; } /** * Checks if the the CAPTCHA was solved correctly * * @param bool $msg when true, an error will be signalled through the msg() method * @return bool true when the answer was correct, otherwise false */ function check($msg=true){ // compare provided string with decrypted captcha $rand = PMA_blowfish_decrypt($_REQUEST['plugin__captcha_secret'],auth_cookiesalt()); $code = $this->_generateCAPTCHA($this->_fixedIdent(),$rand); if(!$_REQUEST['plugin__captcha_secret'] || !$_REQUEST['plugin__captcha'] || strtoupper($_REQUEST['plugin__captcha']) != $code){ if($msg) msg($this->getLang('testfailed'),-1); return false; } return true; } /** * Build a semi-secret fixed string identifying the current page and user * * This string is always the same for the current user when editing the same * page revision. */ function _fixedIdent(){ global $ID; $lm = @filemtime(wikiFN($ID)); return auth_browseruid(). auth_cookiesalt(). $ID.$lm; } /** * Generates a random 5 char string * * @param $fixed string - the fixed part, any string * @param $rand float - some random number between 0 and 1 */ function _generateCAPTCHA($fixed,$rand){ $fixed = hexdec(substr(md5($fixed),5,5)); // use part of the md5 to generate an int $numbers = md5($rand * $fixed); // combine both values // now create the letters $code = ''; for($i=0;$i<10;$i+=2){ $code .= chr(floor(hexdec($numbers[$i].$numbers[$i+1])/10) + 65); } return $code; } /** * Create a CAPTCHA image */ function _imageCAPTCHA($text){ $w = $this->getConf('width'); $h = $this->getConf('height'); $fonts = glob(dirname(__FILE__).'/fonts/*.ttf'); // create a white image $img = imagecreate($w, $h); imagecolorallocate($img, 255, 255, 255); // add some lines as background noise for ($i = 0; $i < 30; $i++) { $color = imagecolorallocate($img,rand(100, 250),rand(100, 250),rand(100, 250)); imageline($img,rand(0,$w),rand(0,$h),rand(0,$w),rand(0,$h),$color); } // draw the letters for ($i = 0; $i < strlen($text); $i++){ $font = $fonts[array_rand($fonts)]; $color = imagecolorallocate($img, rand(0, 100), rand(0, 100), rand(0, 100)); $size = rand(floor($h/1.8),floor($h*0.7)); $angle = rand(-35, 35); $x = ($w*0.05) + $i * floor($w*0.9/5); $cheight = $size + ($size*0.5); $y = floor($h / 2 + $cheight / 3.8); imagettftext($img, $size, $angle, $x, $y, $color, $font, $text[$i]); } header("Content-type: image/png"); imagepng($img); imagedestroy($img); } }