* @copyright © 2006 Rob Church * @licence GNU General Public Licence 2.0 */ if( defined( 'MEDIAWIKI' ) ) { class MathCaptcha extends SimpleCaptcha { /** Validate a captcha response */ function keyMatch( $req, $info ) { return (int)$req->getVal( 'wpCaptchaAnswer' ) == (int)$info['answer']; } /** Produce a nice little form */ function getForm() { list( $sum, $answer ) = $this->pickSum(); $index = $this->storeCaptcha( array( 'answer' => $answer ) ); $form = ''; $form .= '

' . $this->fetchMath( $sum ) . '

' . wfInput( 'wpCaptchaAnswer', false, false, array( 'tabindex' => '1' ) ) . '

'; $form .= wfHidden( 'wpCaptchaId', $index ); return $form; } /** Pick a random sum */ function pickSum() { $a = mt_rand( 0, 100 ); $b = mt_rand( 0, 10 ); $op = mt_rand( 0, 1 ) ? '+' : '-'; $sum = "{$a} {$op} {$b} = "; $ans = $op == '+' ? ( $a + $b ) : ( $a - $b ); return array( $sum, $ans ); } /** Fetch the math */ function fetchMath( $sum ) { $math = new MathRenderer( $sum ); $math->setOutputMode( MW_MATH_PNG ); $html = $math->render(); return preg_replace( '/alt=".*"/', '', $html ); } } } else { echo( "This file is an extension to the MediaWiki software and cannot be used standalone.\n" ); die( 1 ); }