-class FancyCaptcha extends SimpleCaptcha {
- function keyMatch() {
- global $wgRequest, $wgCaptchaSecret;
-
- if( !isset( $_SESSION['ceAnswerVar'] ) ) {
- wfDebug( "FancyCaptcha: no session captcha key set, this is new visitor.\n" );
- return false;
- }
-
- $var = @$_SESSION['ceAnswerVar'];
- $salt = @$_SESSION['captchaSalt'];
- $hash = @$_SESSION['captchaHash'];
-
- $answer = $wgRequest->getVal( $var );
- $digest = $wgCaptchaSecret . $salt . $answer . $wgCaptchaSecret . $salt;
- $answerHash = substr( md5( $digest ), 0, 16 );
-
- if( $answerHash == $hash ) {
- wfDebug( "FancyCaptcha: answer hash matches expected $hash\n" );
- return true;
- } else {
- wfDebug( "FancyCaptcha: answer hashes to $answerHash, expected $hash\n" );
- return false;
- }
- }
-
- /**
- * Insert the captcha prompt into the edit form.
- */
- function formCallback( &$out ) {
- $dest = 'wpCaptchaWord' . mt_rand();
-
- $img = $this->pickImage();
- if( !$img ) {
- die( "out of captcha images; this shouldn't happen" );
- }
-
- $_SESSION['ceAnswerVar'] = $dest;
- $_SESSION['captchaHash'] = $img['hash'];
- $_SESSION['captchaSalt'] = $img['salt'];
- $_SESSION['captchaViewed'] = false;
- wfDebug( "Picked captcha with hash ${img['hash']}, salt ${img['salt']}.\n" );
-
- $title = Title::makeTitle( NS_SPECIAL, 'Captcha/image' );
-
- $out->addWikiText( wfMsg( "captcha-short" ) );
- $out->addHTML( "<p>" .
- wfElement( 'img', array(
- 'src' => $title->getLocalUrl(),
- 'width' => $img['width'],
- 'height' => $img['height'],
- 'alt' => '' ) ) .
- "</p>\n" .
- "<p><input name=\"$dest\" id=\"$dest\" tabindex=\"1\" /></p>" );
- }
-
- /**
- * Select a previously generated captcha image from the queue.
- * @fixme subject to race conditions if lots of files vanish
- * @return mixed tuple of (salt key, text hash) or false if no image to find
- */
- function pickImage() {
- global $wgCaptchaDirectory;
- $pick = mt_rand( 0, $this->countFiles( $wgCaptchaDirectory ) );
- $dir = opendir( $wgCaptchaDirectory );
-
- $n = mt_rand( 0, 16 );
- $count = 0;
-
- $entry = readdir( $dir );
- $pick = false;
- while( false !== $entry ) {
- $entry = readdir( $dir );
- if( preg_match( '/^image_([0-9a-f]+)_([0-9a-f]+)\\.png$/', $entry, $matches ) ) {
- $size = getimagesize( "$wgCaptchaDirectory/$entry" );
- $pick = array(
- 'salt' => $matches[1],
- 'hash' => $matches[2],
- 'width' => $size[0],
- 'height' => $size[1]
- );
- if( $count++ == $n ) {
- break;
- }
- }
- }
- closedir( $dir );
- return $pick;
- }
-
- /**
- * Count the number of files in a directory.
- * @return int
- */
- function countFiles( $dirname ) {
- $dir = opendir( $dirname );
- $count = 0;
- while( false !== ($entry = readdir( $dir ) ) ) {
- if( $dir != '.' && $dir != '..' ) {
- $count++;
- }
- }
- closedir( $dir );
- return $count;
- }
-
- function showImage() {
- global $wgOut;
- $wgOut->disable();
- if( !empty( $_SESSION['captchaViewed'] ) ) {
- wfHttpError( 403, 'Access Forbidden', "Can't view captcha image a second time." );
- return false;
- }
- $_SESSION['captchaViewed'] = wfTimestamp();
-
- if( isset( $_SESSION['captchaSalt'] ) ) {
- $salt = $_SESSION['captchaSalt'];
- if( isset( $_SESSION['captchaHash'] ) ) {
- $hash = $_SESSION['captchaHash'];
-
- global $wgCaptchaDirectory;
- $file = $wgCaptchaDirectory . DIRECTORY_SEPARATOR . "image_{$salt}_{$hash}.png";
- if( file_exists( $file ) ) {
- header( 'Content-type: image/png' );
- readfile( $file );
- }
- }
- } else {
- wfHttpError( 500, 'Internal Error', 'Requested bogus captcha image' );
- }
- }
-}
-
-} # End invocation guard
-
-?>