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             $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 }