FancyCaptcha.class.php

   1 <?php
   2
   3 class FancyCaptcha extends SimpleCaptcha {
   4         /**
   5          * Check if the submitted form matches the captcha session data provided
   6          * by the plugin when the form was generated.
   7          *
   8          * @param string $answer
   9          * @param array $info
  10          * @return bool
  11          */
  12         function keyMatch( $answer, $info ) {
  13                 global $wgCaptchaSecret;
  14
  15                 $digest = $wgCaptchaSecret . $info['salt'] . $answer . $wgCaptchaSecret . $info['salt'];
  16                 $answerHash = substr( md5( $digest ), 0, 16 );
  17
  18                 if( $answerHash == $info['hash'] ) {
  19                         wfDebug( "FancyCaptcha: answer hash matches expected {$info['hash']}\n" );
  20                         return true;
  21                 } else {
  22                         wfDebug( "FancyCaptcha: answer hashes to $answerHash, expected {$info['hash']}\n" );
  23                         return false;
  24                 }
  25         }
  26
  27         function addCaptchaAPI(&$resultArr) {
  28                 $info = $this->pickImage();
  29                 if( !$info ) {
  30                         $resultArr['captcha']['error'] = 'Out of images';
  31                         return;
  32                 }
  33                 $index = $this->storeCaptcha( $info );
  34                 $title = Title::makeTitle( NS_SPECIAL, 'Captcha/image' );
  35                 $resultArr['captcha']['type'] = 'image';
  36                 $resultArr['captcha']['id'] = $index;
  37                 $resultArr['captcha']['url'] = $title->getLocalUrl( 'wpCaptchaId=' . urlencode( $index ) );
  38         }
  39
  40         /**
  41          * Insert the captcha prompt into the edit form.
  42          */
  43         function getForm() {
  44                 $info = $this->pickImage();
  45                 if( !$info ) {
  46                         die( "out of captcha images; this shouldn't happen" );
  47                 }
  48
  49                 // Generate a random key for use of this captcha image in this session.
  50                 // This is needed so multiple edits in separate tabs or windows can
  51                 // go through without extra pain.
  52                 $index = $this->storeCaptcha( $info );
  53
  54                 wfDebug( "Captcha id $index using hash ${info['hash']}, salt ${info['salt']}.\n" );
  55
  56                 $title = Title::makeTitle( NS_SPECIAL, 'Captcha/image' );
  57
  58                 return "<p>" .
  59                         wfElement( 'img', array(
  60                                 'src'    => $title->getLocalUrl( 'wpCaptchaId=' . urlencode( $index ) ),
  61                                 'width'  => $info['width'],
  62                                 'height' => $info['height'],
  63                                 'alt'    => '' ) ) .
  64                         "</p>\n" .
  65                         wfElement( 'input', array(
  66                                 'type'  => 'hidden',
  67                                 'name'  => 'wpCaptchaId',
  68                                 'id'    => 'wpCaptchaId',
  69                                 'value' => $index ) ) .
  70                         "<p>" .
  71                         wfElement( 'input', array(
  72                                 'name' => 'wpCaptchaWord',
  73                                 'id'   => 'wpCaptchaWord',
  74                                 'tabindex' => 1 ) ) . // tab in before the edit textarea
  75                         "</p>\n";
  76         }
  77
  78         /**
  79          * Select a previously generated captcha image from the queue.
  80          * @fixme subject to race conditions if lots of files vanish
  81          * @return mixed tuple of (salt key, text hash) or false if no image to find
  82          */
  83         function pickImage() {
  84                 global $wgCaptchaDirectory, $wgCaptchaDirectoryLevels;
  85                 return $this->pickImageDir(
  86                         $wgCaptchaDirectory,
  87                         $wgCaptchaDirectoryLevels );
  88         }
  89
  90         function pickImageDir( $directory, $levels ) {
  91                 if( $levels ) {
  92                         $dirs = array();
  93
  94                         // Check which subdirs are actually present...
  95                         $dir = opendir( $directory );
  96                         while( false !== ($entry = readdir( $dir ) ) ) {
  97                                 if( ctype_xdigit( $entry ) && strlen( $entry ) == 1 ) {
  98                                         $dirs[] = $entry;
  99                                 }
 100                         }
 101                         closedir( $dir );
 102
 103                         $place = mt_rand( 0, count( $dirs ) - 1 );
 104                         // In case all dirs are not filled,
 105                         // cycle through next digits...
 106                         for( $j = 0; $j < count( $dirs ); $j++ ) {
 107                                 $char = $dirs[($place + $j) % count( $dirs )];
 108                                 $return = $this->pickImageDir( "$directory/$char", $levels - 1 );
 109                                 if( $return ) {
 110                                         return $return;
 111                                 }
 112                         }
 113                         // Didn't find any images in this directory... empty?
 114                         return false;
 115                 } else {
 116                         return $this->pickImageFromDir( $directory );
 117                 }
 118         }
 119
 120         function pickImageFromDir( $directory ) {
 121                 if( !is_dir( $directory ) ) {
 122                         return false;
 123                 }
 124                 $n = mt_rand( 0, $this->countFiles( $directory ) - 1 );
 125                 $dir = opendir( $directory );
 126
 127                 $count = 0;
 128
 129                 $entry = readdir( $dir );
 130                 $pick = false;
 131                 while( false !== $entry ) {
 132                         $entry = readdir( $dir );
 133                         if( preg_match( '/^image_([0-9a-f]+)_([0-9a-f]+)\\.png$/', $entry, $matches ) ) {
 134                                 $size = getimagesize( "$directory/$entry" );
 135                                 $pick = array(
 136                                         'salt' => $matches[1],
 137                                         'hash' => $matches[2],
 138                                         'width' => $size[0],
 139                                         'height' => $size[1],
 140                                         'viewed' => false,
 141                                 );
 142                                 if( $count++ == $n ) {
 143                                         break;
 144                                 }
 145                         }
 146                 }
 147                 closedir( $dir );
 148                 return $pick;
 149         }
 150
 151         /**
 152          * Count the number of files in a directory.
 153          * @return int
 154          */
 155         function countFiles( $dirname ) {
 156                 $dir = opendir( $dirname );
 157                 $count = 0;
 158                 while( false !== ($entry = readdir( $dir ) ) ) {
 159                         if( $entry != '.' && $entry != '..' ) {
 160                                 $count++;
 161                         }
 162                 }
 163                 closedir( $dir );
 164                 return $count;
 165         }
 166
 167         function showImage() {
 168                 global $wgOut, $wgRequest;
 169
 170                 $wgOut->disable();
 171
 172                 $info = $this->retrieveCaptcha();
 173                 if( $info ) {
 174                         /*
 175                         // Be a little less restrictive for now; in at least some circumstances,
 176                         // Konqueror tries to reload the image even if you haven't navigated
 177                         // away from the page.
 178                         if( $info['viewed'] ) {
 179                                 wfHttpError( 403, 'Access Forbidden', "Can't view captcha image a second time." );
 180                                 return false;
 181                         }
 182                         */
 183
 184                         $info['viewed'] = wfTimestamp();
 185                         $this->storeCaptcha( $info );
 186
 187                         $salt = $info['salt'];
 188                         $hash = $info['hash'];
 189                         $file = $this->imagePath( $salt, $hash );
 190
 191                         if( file_exists( $file ) ) {
 192                                 global $IP;
 193                                 require_once "$IP/includes/StreamFile.php";
 194                                 header( "Cache-Control: private, s-maxage=0, max-age=3600" );
 195                                 wfStreamFile( $file );
 196                                 return true;
 197                         }
 198                 }
 199                 wfHttpError( 500, 'Internal Error', 'Requested bogus captcha image' );
 200                 return false;
 201         }
 202
 203         function imagePath( $salt, $hash ) {
 204                 global $wgCaptchaDirectory, $wgCaptchaDirectoryLevels;
 205                 $file = $wgCaptchaDirectory;
 206                 $file .= DIRECTORY_SEPARATOR;
 207                 for( $i = 0; $i < $wgCaptchaDirectoryLevels; $i++ ) {
 208                         $file .= $hash{$i};
 209                         $file .= DIRECTORY_SEPARATOR;
 210                 }
 211                 $file .= "image_{$salt}_{$hash}.png";
 212                 return $file;
 213         }
 214
 215         /**
 216          * Show a message asking the user to enter a captcha on edit
 217          * The result will be treated as wiki text
 218          *
 219          * @param $action Action being performed
 220          * @return string
 221          */
 222         function getMessage( $action ) {
 223                 $name = 'fancycaptcha-' . $action;
 224                 $text = wfMsg( $name );
 225                 # Obtain a more tailored message, if possible, otherwise, fall back to
 226                 # the default for edits
 227                 return wfEmptyMsg( $name, $text ) ? wfMsg( 'fancycaptcha-edit' ) : $text;
 228         }
 229
 230 }