theme/image.php

   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             // 90 days only - based on Moodle point release cadence being every 3 months.
 111             $lifetime = 60 * 60 * 24 * 90;
 112             $mimetype = get_contenttype_from_ext($ext);
 113             header('HTTP/1.1 304 Not Modified');
 114             header('Expires: '. gmdate('D, d M Y H:i:s', time() + $lifetime) .' GMT');
 115             header('Cache-Control: public, max-age='.$lifetime.', no-transform');
 116             header('Content-Type: '.$mimetype);
 117             header('Etag: "'.$etag.'"');
 118             die;
 119         }
 120         send_cached_image($cacheimage, $etag);
 121     }
 122 }
 123
 124 //=================================================================================
 125 // ok, now we need to start normal moodle script, we need to load all libs and $DB
 126 define('ABORT_AFTER_CONFIG_CANCEL', true);
 127
 128 define('NO_MOODLE_COOKIES', true); // Session not used here
 129 define('NO_UPGRADE_CHECK', true);  // Ignore upgrade check
 130
 131 require("$CFG->dirroot/lib/setup.php");
 132
 133 $theme = theme_config::load($themename);
 134 $themerev = theme_get_revision();
 135
 136 if ($themerev <= 0 or $rev != $themerev) {
 137     // Do not send caching headers if they do not request current revision,
 138     // we do not want to pollute browser caches with outdated images.
 139     $imagefile = $theme->resolve_image_location($image, $component, $usesvg);
 140     if (empty($imagefile) or !is_readable($imagefile)) {
 141         image_not_found();
 142     }
 143     send_uncached_image($imagefile);
 144 }
 145
 146 make_localcache_directory('theme', false);
 147
 148 // At this stage caching is enabled, and either:
 149 // * we have no cached copy of the image in any format (either SVG, or non-SVG); or
 150 // * we have a cached copy of the SVG, but the non-SVG was requested by the browser.
 151 //
 152 // Because of the way in which the cache return code works above:
 153 // * if we are allowed to return SVG, we do not need to cache the non-SVG version; however
 154 // * if the browser has requested the non-SVG version, we *must* cache _both_ the SVG, and the non-SVG versions.
 155
 156 // First get all copies - including, potentially, the SVG version.
 157 $imagefile = $theme->resolve_image_location($image, $component, true);
 158
 159 if (empty($imagefile) || !is_readable($imagefile)) {
 160     // Unable to find a copy of the image file in any format.
 161     // We write a .error file for the image now - this will be used above when searching for cached copies to prevent
 162     // trying to find the image in the future.
 163     if (!file_exists($candidatelocation)) {
 164         @mkdir($candidatelocation, $CFG->directorypermissions, true);
 165     }
 166     // Make note we can not find this file.
 167     $cacheimage = "$candidatelocation/$image.error";
 168     $fp = fopen($cacheimage, 'w');
 169     fclose($fp);
 170     image_not_found();
 171 }
 172
 173 // The image was found, and it is readable.
 174 $pathinfo = pathinfo($imagefile);
 175
 176 // Attempt to cache it if necessary.
 177 // We don't really want to overwrite any existing cache items just for the sake of it.
 178 $cacheimage = "$candidatelocation/$image.{$pathinfo['extension']}";
 179 if (!file_exists($cacheimage)) {
 180     // We don't already hold a cached copy of this image. Cache it now.
 181     $cacheimage = cache_image($image, $imagefile, $candidatelocation);
 182 }
 183
 184 if (!$usesvg && $pathinfo['extension'] === 'svg') {
 185     // The browser has requested that a non-SVG version be returned.
 186     // The version found so far is the SVG version - try and find the non-SVG version.
 187     $imagefile = $theme->resolve_image_location($image, $component, false);
 188     if (empty($imagefile) || !is_readable($imagefile)) {
 189         // A non-SVG file could not be found at all.
 190         // The browser has requested a non-SVG version, so we must return image_not_found().
 191         // We must *not* write an .error file because the SVG is available.
 192         image_not_found();
 193     }
 194
 195     // An non-SVG version of image was found - cache it.
 196     // This will be used below in the image serving code.
 197     $cacheimage = cache_image($image, $imagefile, $candidatelocation);
 198 }
 199
 200 if (connection_aborted()) {
 201     // Request was cancelled - do not send anything.
 202     die;
 203 }
 204
 205 // Make sure nothing failed.
 206 clearstatcache();
 207 if (file_exists($cacheimage)) {
 208     // The cached copy was found, and is accessible. Serve it.
 209     send_cached_image($cacheimage, $etag);
 210 }
 211
 212 send_uncached_image($imagefile);
 213
 214 //=================================================================================
 215 //=== utility functions ==
 216 // we are not using filelib because we need to fine tune all header
 217 // parameters to get the best performance.
 218
 219 function send_cached_image($imagepath, $etag) {
 220     global $CFG;
 221     require("$CFG->dirroot/lib/xsendfilelib.php");
 222
 223     // 90 days only - based on Moodle point release cadence being every 3 months.
 224     $lifetime = 60 * 60 * 24 * 90;
 225     $pathinfo = pathinfo($imagepath);
 226     $imagename = $pathinfo['filename'].'.'.$pathinfo['extension'];
 227
 228     $mimetype = get_contenttype_from_ext($pathinfo['extension']);
 229
 230     header('Etag: "'.$etag.'"');
 231     header('Content-Disposition: inline; filename="'.$imagename.'"');
 232     header('Last-Modified: '. gmdate('D, d M Y H:i:s', filemtime($imagepath)) .' GMT');
 233     header('Expires: '. gmdate('D, d M Y H:i:s', time() + $lifetime) .' GMT');
 234     header('Pragma: ');
 235     header('Cache-Control: public, max-age='.$lifetime.', no-transform, immutable');
 236     header('Accept-Ranges: none');
 237     header('Content-Type: '.$mimetype);
 238
 239     if (xsendfile($imagepath)) {
 240         die;
 241     }
 242
 243     if ($mimetype === 'image/svg+xml') {
 244         // SVG format is a text file. So we can compress SVG files.
 245         if (!min_enable_zlib_compression()) {
 246             header('Content-Length: '.filesize($imagepath));
 247         }
 248     } else {
 249         // No need to compress other image formats.
 250         header('Content-Length: '.filesize($imagepath));
 251     }
 252
 253     readfile($imagepath);
 254     die;
 255 }
 256
 257 function send_uncached_image($imagepath) {
 258     $pathinfo = pathinfo($imagepath);
 259     $imagename = $pathinfo['filename'].'.'.$pathinfo['extension'];
 260
 261     $mimetype = get_contenttype_from_ext($pathinfo['extension']);
 262
 263     header('Content-Disposition: inline; filename="'.$imagename.'"');
 264     header('Last-Modified: '. gmdate('D, d M Y H:i:s', time()) .' GMT');
 265     header('Expires: '. gmdate('D, d M Y H:i:s', time() + 15) .' GMT');
 266     header('Pragma: ');
 267     header('Accept-Ranges: none');
 268     header('Content-Type: '.$mimetype);
 269     header('Content-Length: '.filesize($imagepath));
 270
 271     readfile($imagepath);
 272     die;
 273 }
 274
 275 function image_not_found() {
 276     header('HTTP/1.0 404 not found');
 277     die('Image was not found, sorry.');
 278 }
 279
 280 function get_contenttype_from_ext($ext) {
 281     switch ($ext) {
 282         case 'svg':
 283             return 'image/svg+xml';
 284         case 'png':
 285             return 'image/png';
 286         case 'gif':
 287             return 'image/gif';
 288         case 'jpg':
 289         case 'jpeg':
 290             return 'image/jpeg';
 291         case 'ico':
 292             return 'image/vnd.microsoft.icon';
 293     }
 294     return 'document/unknown';
 295 }
 296
 297 /**
 298  * Caches a given image file.
 299  *
 300  * @param string $image The name of the image that was requested.
 301  * @param string $imagefile The location of the image file we want to cache.
 302  * @param string $candidatelocation The location to cache it in.
 303  * @return string The path to the cached image.
 304  */
 305 function cache_image($image, $imagefile, $candidatelocation) {
 306     global $CFG;
 307     $pathinfo = pathinfo($imagefile);
 308     $cacheimage = "$candidatelocation/$image.".$pathinfo['extension'];
 309
 310     clearstatcache();
 311     if (!file_exists(dirname($cacheimage))) {
 312         @mkdir(dirname($cacheimage), $CFG->directorypermissions, true);
 313     }
 314
 315     // Prevent serving of incomplete file from concurrent request,
 316     // the rename() should be more atomic than copy().
 317     ignore_user_abort(true);
 318     if (@copy($imagefile, $cacheimage.'.tmp')) {
 319         rename($cacheimage.'.tmp', $cacheimage);
 320         @chmod($cacheimage, $CFG->filepermissions);
 321         @unlink($cacheimage.'.tmp'); // just in case anything fails
 322     }
 323     return $cacheimage;
 324 }