pickSum(); $index = $this->storeCaptcha( array( 'answer' => $answer ) ); $resultArr['captcha']['type'] = 'math'; $resultArr['captcha']['mime'] = 'text/tex'; $resultArr['captcha']['id'] = $index; $resultArr['captcha']['question'] = $sum; } /** Produce a nice little form */ function getForm() { list( $sum, $answer ) = $this->pickSum(); $index = $this->storeCaptcha( array( 'answer' => $answer ) ); $form = ''; $form .= '

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

' . Html::input( 'wpCaptchaWord', false, false, array( 'tabindex' => '1', 'required' ) ) . '

'; $form .= Html::hidden( '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 ) { if ( MWInit::classExists( 'MathRenderer' ) ) { $math = new MathRenderer( $sum ); } else { throw new MWException( 'MathCaptcha requires the Math extension for MediaWiki versions 1.18 and above.' ); } $math->setOutputMode( MW_MATH_PNG ); $html = $math->render(); return preg_replace( '/alt=".*?"/', '', $html ); } }