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   1  <?php
   2  // This file is part of Moodle - http://moodle.org/
   3  //
   4  // Moodle is free software: you can redistribute it and/or modify
   5  // it under the terms of the GNU General Public License as published by
   6  // the Free Software Foundation, either version 3 of the License, or
   7  // (at your option) any later version.
   8  //
   9  // Moodle is distributed in the hope that it will be useful,
  10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  // GNU General Public License for more details.
  13  //
  14  // You should have received a copy of the GNU General Public License
  15  // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  16  
  17  /**
  18   * This file is responsible for serving the one theme and plugin images.
  19   *
  20   * @package   core
  21   * @copyright 2009 Petr Skoda (skodak)  {@link http://skodak.org}
  22   * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  23   */
  24  
  25  
  26  // disable moodle specific debug messages and any errors in output,
  27  // comment out when debugging or better look into error log!
  28  define('NO_DEBUG_DISPLAY', true);
  29  
  30  // we need just the values from config.php and minlib.php
  31  define('ABORT_AFTER_CONFIG', true);
  32  require('../config.php'); // this stops immediately at the beginning of lib/setup.php
  33  
  34  if ($slashargument = min_get_slash_argument()) {
  35      $slashargument = ltrim($slashargument, '/');
  36      if (substr_count($slashargument, '/') < 3) {
  37          image_not_found();
  38      }
  39      if (strpos($slashargument, '_s/') === 0) {
  40          // Can't use SVG
  41          $slashargument = substr($slashargument, 3);
  42          $usesvg = false;
  43      } else {
  44          $usesvg = true;
  45      }
  46      // image must be last because it may contain "/"
  47      list($themename, $component, $rev, $image) = explode('/', $slashargument, 4);
  48      $themename = min_clean_param($themename, 'SAFEDIR');
  49      $component = min_clean_param($component, 'SAFEDIR');
  50      $rev       = min_clean_param($rev, 'INT');
  51      $image     = min_clean_param($image, 'SAFEPATH');
  52  
  53  } else {
  54      $themename = min_optional_param('theme', 'standard', 'SAFEDIR');
  55      $component = min_optional_param('component', 'core', 'SAFEDIR');
  56      $rev       = min_optional_param('rev', -1, 'INT');
  57      $image     = min_optional_param('image', '', 'SAFEPATH');
  58      $usesvg    = (bool)min_optional_param('svg', '1', 'INT');
  59  }
  60  
  61  if (empty($component) or $component === 'moodle' or $component === 'core') {
  62      $component = 'core';
  63  }
  64  
  65  if (empty($image)) {
  66      image_not_found();
  67  }
  68  
  69  if (file_exists("$CFG->dirroot/theme/$themename/config.php")) {
  70      // exists
  71  } else if (!empty($CFG->themedir) and file_exists("$CFG->themedir/$themename/config.php")) {
  72      // exists
  73  } else {
  74      image_not_found();
  75  }
  76  
  77  $candidatelocation = "$CFG->localcachedir/theme/$rev/$themename/pix/$component";
  78  $etag = sha1("$rev/$themename/$component/$image");
  79  
  80  if ($rev > 0) {
  81      if (file_exists("$candidatelocation/$image.error")) {
  82          // This is a major speedup if there are multiple missing images,
  83          // the only problem is that random requests may pollute our cache.
  84          image_not_found();
  85      }
  86      $cacheimage = false;
  87      if ($usesvg && file_exists("$candidatelocation/$image.svg")) {
  88          $cacheimage = "$candidatelocation/$image.svg";
  89          $ext = 'svg';
  90      } else if (file_exists("$candidatelocation/$image.png")) {
  91          $cacheimage = "$candidatelocation/$image.png";
  92          $ext = 'png';
  93      } else if (file_exists("$candidatelocation/$image.gif")) {
  94          $cacheimage = "$candidatelocation/$image.gif";
  95          $ext = 'gif';
  96      } else if (file_exists("$candidatelocation/$image.jpg")) {
  97          $cacheimage = "$candidatelocation/$image.jpg";
  98          $ext = 'jpg';
  99      } else if (file_exists("$candidatelocation/$image.jpeg")) {
 100          $cacheimage = "$candidatelocation/$image.jpeg";
 101          $ext = 'jpeg';
 102      } else if (file_exists("$candidatelocation/$image.ico")) {
 103          $cacheimage = "$candidatelocation/$image.ico";
 104          $ext = 'ico';
 105      }
 106      if ($cacheimage) {
 107          if (!empty($_SERVER['HTTP_IF_NONE_MATCH']) || !empty($_SERVER['HTTP_IF_MODIFIED_SINCE'])) {
 108              // we do not actually need to verify the etag value because our files
 109              // never change in cache because we increment the rev parameter
 110              $lifetime = 60*60*24*60; // 60 days only - the revision may get incremented quite often
 111              $mimetype = get_contenttype_from_ext($ext);
 112              header('HTTP/1.1 304 Not Modified');
 113              header('Expires: '. gmdate('D, d M Y H:i:s', time() + $lifetime) .' GMT');
 114              header('Cache-Control: public, max-age='.$lifetime.', no-transform');
 115              header('Content-Type: '.$mimetype);
 116              header('Etag: "'.$etag.'"');
 117              die;
 118          }
 119          send_cached_image($cacheimage, $etag);
 120      }
 121  }
 122  
 123  //=================================================================================
 124  // ok, now we need to start normal moodle script, we need to load all libs and $DB
 125  define('ABORT_AFTER_CONFIG_CANCEL', true);
 126  
 127  define('NO_MOODLE_COOKIES', true); // Session not used here
 128  define('NO_UPGRADE_CHECK', true);  // Ignore upgrade check
 129  
 130  require("$CFG->dirroot/lib/setup.php");
 131  
 132  $theme = theme_config::load($themename);
 133  $themerev = theme_get_revision();
 134  
 135  if ($themerev <= 0 or $rev != $themerev) {
 136      // Do not send caching headers if they do not request current revision,
 137      // we do not want to pollute browser caches with outdated images.
 138      $imagefile = $theme->resolve_image_location($image, $component, $usesvg);
 139      if (empty($imagefile) or !is_readable($imagefile)) {
 140          image_not_found();
 141      }
 142      send_uncached_image($imagefile);
 143  }
 144  
 145  make_localcache_directory('theme', false);
 146  
 147  // At this stage caching is enabled, and either:
 148  // * we have no cached copy of the image in any format (either SVG, or non-SVG); or
 149  // * we have a cached copy of the SVG, but the non-SVG was requested by the browser.
 150  //
 151  // Because of the way in which the cache return code works above:
 152  // * if we are allowed to return SVG, we do not need to cache the non-SVG version; however
 153  // * if the browser has requested the non-SVG version, we *must* cache _both_ the SVG, and the non-SVG versions.
 154  
 155  // First get all copies - including, potentially, the SVG version.
 156  $imagefile = $theme->resolve_image_location($image, $component, true);
 157  
 158  if (empty($imagefile) || !is_readable($imagefile)) {
 159      // Unable to find a copy of the image file in any format.
 160      // We write a .error file for the image now - this will be used above when searching for cached copies to prevent
 161      // trying to find the image in the future.
 162      if (!file_exists($candidatelocation)) {
 163          @mkdir($candidatelocation, $CFG->directorypermissions, true);
 164      }
 165      // Make note we can not find this file.
 166      $cacheimage = "$candidatelocation/$image.error";
 167      $fp = fopen($cacheimage, 'w');
 168      fclose($fp);
 169      image_not_found();
 170  }
 171  
 172  // The image was found, and it is readable.
 173  $pathinfo = pathinfo($imagefile);
 174  
 175  // Attempt to cache it if necessary.
 176  // We don't really want to overwrite any existing cache items just for the sake of it.
 177  $cacheimage = "$candidatelocation/$image.{$pathinfo['extension']}";
 178  if (!file_exists($cacheimage)) {
 179      // We don't already hold a cached copy of this image. Cache it now.
 180      $cacheimage = cache_image($image, $imagefile, $candidatelocation);
 181  }
 182  
 183  if (!$usesvg && $pathinfo['extension'] === 'svg') {
 184      // The browser has requested that a non-SVG version be returned.
 185      // The version found so far is the SVG version - try and find the non-SVG version.
 186      $imagefile = $theme->resolve_image_location($image, $component, false);
 187      if (empty($imagefile) || !is_readable($imagefile)) {
 188          // A non-SVG file could not be found at all.
 189          // The browser has requested a non-SVG version, so we must return image_not_found().
 190          // We must *not* write an .error file because the SVG is available.
 191          image_not_found();
 192      }
 193  
 194      // An non-SVG version of image was found - cache it.
 195      // This will be used below in the image serving code.
 196      $cacheimage = cache_image($image, $imagefile, $candidatelocation);
 197  }
 198  
 199  if (connection_aborted()) {
 200      // Request was cancelled - do not send anything.
 201      die;
 202  }
 203  
 204  // Make sure nothing failed.
 205  clearstatcache();
 206  if (file_exists($cacheimage)) {
 207      // The cached copy was found, and is accessible. Serve it.
 208      send_cached_image($cacheimage, $etag);
 209  }
 210  
 211  send_uncached_image($imagefile);
 212  
 213  //=================================================================================
 214  //=== utility functions ==
 215  // we are not using filelib because we need to fine tune all header
 216  // parameters to get the best performance.
 217  
 218  function send_cached_image($imagepath, $etag) {
 219      global $CFG;
 220      require("$CFG->dirroot/lib/xsendfilelib.php");
 221  
 222      $lifetime = 60*60*24*60; // 60 days only - the revision may get incremented quite often
 223      $pathinfo = pathinfo($imagepath);
 224      $imagename = $pathinfo['filename'].'.'.$pathinfo['extension'];
 225  
 226      $mimetype = get_contenttype_from_ext($pathinfo['extension']);
 227  
 228      header('Etag: "'.$etag.'"');
 229      header('Content-Disposition: inline; filename="'.$imagename.'"');
 230      header('Last-Modified: '. gmdate('D, d M Y H:i:s', filemtime($imagepath)) .' GMT');
 231      header('Expires: '. gmdate('D, d M Y H:i:s', time() + $lifetime) .' GMT');
 232      header('Pragma: ');
 233      header('Cache-Control: public, max-age='.$lifetime.', no-transform');
 234      header('Accept-Ranges: none');
 235      header('Content-Type: '.$mimetype);
 236      header('Content-Length: '.filesize($imagepath));
 237  
 238      if (xsendfile($imagepath)) {
 239          die;
 240      }
 241  
 242      // no need to gzip already compressed images ;-)
 243  
 244      readfile($imagepath);
 245      die;
 246  }
 247  
 248  function send_uncached_image($imagepath) {
 249      $pathinfo = pathinfo($imagepath);
 250      $imagename = $pathinfo['filename'].'.'.$pathinfo['extension'];
 251  
 252      $mimetype = get_contenttype_from_ext($pathinfo['extension']);
 253  
 254      header('Content-Disposition: inline; filename="'.$imagename.'"');
 255      header('Last-Modified: '. gmdate('D, d M Y H:i:s', time()) .' GMT');
 256      header('Expires: '. gmdate('D, d M Y H:i:s', time() + 15) .' GMT');
 257      header('Pragma: ');
 258      header('Accept-Ranges: none');
 259      header('Content-Type: '.$mimetype);
 260      header('Content-Length: '.filesize($imagepath));
 261  
 262      readfile($imagepath);
 263      die;
 264  }
 265  
 266  function image_not_found() {
 267      header('HTTP/1.0 404 not found');
 268      die('Image was not found, sorry.');
 269  }
 270  
 271  function get_contenttype_from_ext($ext) {
 272      switch ($ext) {
 273          case 'svg':
 274              return 'image/svg+xml';
 275          case 'png':
 276              return 'image/png';
 277          case 'gif':
 278              return 'image/gif';
 279          case 'jpg':
 280          case 'jpeg':
 281              return 'image/jpeg';
 282          case 'ico':
 283              return 'image/vnd.microsoft.icon';
 284      }
 285      return 'document/unknown';
 286  }
 287  
 288  /**
 289   * Caches a given image file.
 290   *
 291   * @param string $image The name of the image that was requested.
 292   * @param string $imagefile The location of the image file we want to cache.
 293   * @param string $candidatelocation The location to cache it in.
 294   * @return string The path to the cached image.
 295   */
 296  function cache_image($image, $imagefile, $candidatelocation) {
 297      global $CFG;
 298      $pathinfo = pathinfo($imagefile);
 299      $cacheimage = "$candidatelocation/$image.".$pathinfo['extension'];
 300  
 301      clearstatcache();
 302      if (!file_exists(dirname($cacheimage))) {
 303          @mkdir(dirname($cacheimage), $CFG->directorypermissions, true);
 304      }
 305  
 306      // Prevent serving of incomplete file from concurrent request,
 307      // the rename() should be more atomic than copy().
 308      ignore_user_abort(true);
 309      if (@copy($imagefile, $cacheimage.'.tmp')) {
 310          rename($cacheimage.'.tmp', $cacheimage);
 311          @chmod($cacheimage, $CFG->filepermissions);
 312          @unlink($cacheimage.'.tmp'); // just in case anything fails
 313      }
 314      return $cacheimage;
 315  }