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<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Moodle. If not, see <http://www.gnu.org/licenses/>.
/**
* This file is responsible for serving the one theme and plugin images.
*
* @package core
* @copyright 2009 Petr Skoda (skodak) {@link http://skodak.org}
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
// disable moodle specific debug messages and any errors in output,
// comment out when debugging or better look into error log!
define('NO_DEBUG_DISPLAY', true);
// we need just the values from config.php and minlib.php
define('ABORT_AFTER_CONFIG', true);
require('../config.php'); // this stops immediately at the beginning of lib/setup.php
if ($slashargument = min_get_slash_argument()) {
$slashargument = ltrim($slashargument, '/');
if (substr_count($slashargument, '/') < 3) {
image_not_found();
}
if (strpos($slashargument, '_s/') === 0) {
// Can't use SVG
$slashargument = substr($slashargument, 3);
$usesvg = false;
} else {
$usesvg = true;
}
// image must be last because it may contain "/"
list($themename, $component, $rev, $image) = explode('/', $slashargument, 4);
$themename = min_clean_param($themename, 'SAFEDIR');
$component = min_clean_param($component, 'SAFEDIR');
$rev = min_clean_param($rev, 'INT');
$image = min_clean_param($image, 'SAFEPATH');
} else {
$themename = min_optional_param('theme', 'standard', 'SAFEDIR');
$component = min_optional_param('component', 'core', 'SAFEDIR');
$rev = min_optional_param('rev', -1, 'INT');
$image = min_optional_param('image', '', 'SAFEPATH');
$usesvg = (bool)min_optional_param('svg', '1', 'INT');
}
if (empty($component) or $component === 'moodle' or $component === 'core') {
$component = 'core';
}
if (empty($image)) {
image_not_found();
}
if (file_exists("$CFG->dirroot/theme/$themename/config.php")) {
// exists
} else if (!empty($CFG->themedir) and file_exists("$CFG->themedir/$themename/config.php")) {
// exists
} else {
image_not_found();
}
$candidatelocation = "$CFG->localcachedir/theme/$rev/$themename/pix/$component";
$etag = sha1("$rev/$themename/$component/$image");
if ($rev > 0) {
if (file_exists("$candidatelocation/$image.error")) {
// This is a major speedup if there are multiple missing images,
// the only problem is that random requests may pollute our cache.
image_not_found();
}
$cacheimage = false;
if ($usesvg && file_exists("$candidatelocation/$image.svg")) {
$cacheimage = "$candidatelocation/$image.svg";
$ext = 'svg';
} else if (file_exists("$candidatelocation/$image.png")) {
$cacheimage = "$candidatelocation/$image.png";
$ext = 'png';
} else if (file_exists("$candidatelocation/$image.gif")) {
$cacheimage = "$candidatelocation/$image.gif";
$ext = 'gif';
} else if (file_exists("$candidatelocation/$image.jpg")) {
$cacheimage = "$candidatelocation/$image.jpg";
$ext = 'jpg';
} else if (file_exists("$candidatelocation/$image.jpeg")) {
$cacheimage = "$candidatelocation/$image.jpeg";
$ext = 'jpeg';
} else if (file_exists("$candidatelocation/$image.ico")) {
$cacheimage = "$candidatelocation/$image.ico";
$ext = 'ico';
}
if ($cacheimage) {
if (!empty($_SERVER['HTTP_IF_NONE_MATCH']) || !empty($_SERVER['HTTP_IF_MODIFIED_SINCE'])) {
// We do not actually need to verify the etag value because our files
// never change in cache because we increment the rev parameter.
// 90 days only - based on Moodle point release cadence being every 3 months.
$lifetime = 60 * 60 * 24 * 90;
$mimetype = get_contenttype_from_ext($ext);
header('HTTP/1.1 304 Not Modified');
header('Expires: '. gmdate('D, d M Y H:i:s', time() + $lifetime) .' GMT');
header('Cache-Control: public, max-age='.$lifetime.', no-transform');
header('Content-Type: '.$mimetype);
header('Etag: "'.$etag.'"');
die;
}
send_cached_image($cacheimage, $etag);
}
}
//=================================================================================
// ok, now we need to start normal moodle script, we need to load all libs and $DB
define('ABORT_AFTER_CONFIG_CANCEL', true);
define('NO_MOODLE_COOKIES', true); // Session not used here
define('NO_UPGRADE_CHECK', true); // Ignore upgrade check
require("$CFG->dirroot/lib/setup.php");
$theme = theme_config::load($themename);
$themerev = theme_get_revision();
if ($themerev <= 0 or $rev != $themerev) {
// Do not send caching headers if they do not request current revision,
// we do not want to pollute browser caches with outdated images.
$imagefile = $theme->resolve_image_location($image, $component, $usesvg);
if (empty($imagefile) or !is_readable($imagefile)) {
image_not_found();
}
send_uncached_image($imagefile);
}
make_localcache_directory('theme', false);
// At this stage caching is enabled, and either:
// * we have no cached copy of the image in any format (either SVG, or non-SVG); or
// * we have a cached copy of the SVG, but the non-SVG was requested by the browser.
//
// Because of the way in which the cache return code works above:
// * if we are allowed to return SVG, we do not need to cache the non-SVG version; however
// * if the browser has requested the non-SVG version, we *must* cache _both_ the SVG, and the non-SVG versions.
// First get all copies - including, potentially, the SVG version.
$imagefile = $theme->resolve_image_location($image, $component, true);
if (empty($imagefile) || !is_readable($imagefile)) {
// Unable to find a copy of the image file in any format.
// We write a .error file for the image now - this will be used above when searching for cached copies to prevent
// trying to find the image in the future.
if (!file_exists($candidatelocation)) {
@mkdir($candidatelocation, $CFG->directorypermissions, true);
}
// Make note we can not find this file.
$cacheimage = "$candidatelocation/$image.error";
$fp = fopen($cacheimage, 'w');
fclose($fp);
image_not_found();
}
// The image was found, and it is readable.
$pathinfo = pathinfo($imagefile);
// Attempt to cache it if necessary.
// We don't really want to overwrite any existing cache items just for the sake of it.
$cacheimage = "$candidatelocation/$image.{$pathinfo['extension']}";
if (!file_exists($cacheimage)) {
// We don't already hold a cached copy of this image. Cache it now.
$cacheimage = cache_image($image, $imagefile, $candidatelocation);
}
if (!$usesvg && $pathinfo['extension'] === 'svg') {
// The browser has requested that a non-SVG version be returned.
// The version found so far is the SVG version - try and find the non-SVG version.
$imagefile = $theme->resolve_image_location($image, $component, false);
if (empty($imagefile) || !is_readable($imagefile)) {
// A non-SVG file could not be found at all.
// The browser has requested a non-SVG version, so we must return image_not_found().
// We must *not* write an .error file because the SVG is available.
image_not_found();
}
// An non-SVG version of image was found - cache it.
// This will be used below in the image serving code.
$cacheimage = cache_image($image, $imagefile, $candidatelocation);
}
if (connection_aborted()) {
// Request was cancelled - do not send anything.
die;
}
// Make sure nothing failed.
clearstatcache();
if (file_exists($cacheimage)) {
// The cached copy was found, and is accessible. Serve it.
send_cached_image($cacheimage, $etag);
}
send_uncached_image($imagefile);
//=================================================================================
//=== utility functions ==
// we are not using filelib because we need to fine tune all header
// parameters to get the best performance.
function send_cached_image($imagepath, $etag) {
global $CFG;
require("$CFG->dirroot/lib/xsendfilelib.php");
// 90 days only - based on Moodle point release cadence being every 3 months.
$lifetime = 60 * 60 * 24 * 90;
$pathinfo = pathinfo($imagepath);
$imagename = $pathinfo['filename'].'.'.$pathinfo['extension'];
$mimetype = get_contenttype_from_ext($pathinfo['extension']);
header('Etag: "'.$etag.'"');
header('Content-Disposition: inline; filename="'.$imagename.'"');
header('Last-Modified: '. gmdate('D, d M Y H:i:s', filemtime($imagepath)) .' GMT');
header('Expires: '. gmdate('D, d M Y H:i:s', time() + $lifetime) .' GMT');
header('Pragma: ');
header('Cache-Control: public, max-age='.$lifetime.', no-transform, immutable');
header('Accept-Ranges: none');
header('Content-Type: '.$mimetype);
if (xsendfile($imagepath)) {
die;
}
if ($mimetype === 'image/svg+xml') {
// SVG format is a text file. So we can compress SVG files.
if (!min_enable_zlib_compression()) {
header('Content-Length: '.filesize($imagepath));
}
} else {
// No need to compress other image formats.
header('Content-Length: '.filesize($imagepath));
}
readfile($imagepath);
die;
}
function send_uncached_image($imagepath) {
$pathinfo = pathinfo($imagepath);
$imagename = $pathinfo['filename'].'.'.$pathinfo['extension'];
$mimetype = get_contenttype_from_ext($pathinfo['extension']);
header('Content-Disposition: inline; filename="'.$imagename.'"');
header('Last-Modified: '. gmdate('D, d M Y H:i:s', time()) .' GMT');
header('Expires: '. gmdate('D, d M Y H:i:s', time() + 15) .' GMT');
header('Pragma: ');
header('Accept-Ranges: none');
header('Content-Type: '.$mimetype);
header('Content-Length: '.filesize($imagepath));
readfile($imagepath);
die;
}
function image_not_found() {
header('HTTP/1.0 404 not found');
die('Image was not found, sorry.');
}
function get_contenttype_from_ext($ext) {
switch ($ext) {
case 'svg':
return 'image/svg+xml';
case 'png':
return 'image/png';
case 'gif':
return 'image/gif';
case 'jpg':
case 'jpeg':
return 'image/jpeg';
case 'ico':
return 'image/vnd.microsoft.icon';
}
return 'document/unknown';
}
/**
* Caches a given image file.
*
* @param string $image The name of the image that was requested.
* @param string $imagefile The location of the image file we want to cache.
* @param string $candidatelocation The location to cache it in.
* @return string The path to the cached image.
*/
function cache_image($image, $imagefile, $candidatelocation) {
global $CFG;
$pathinfo = pathinfo($imagefile);
$cacheimage = "$candidatelocation/$image.".$pathinfo['extension'];
clearstatcache();
if (!file_exists(dirname($cacheimage))) {
@mkdir(dirname($cacheimage), $CFG->directorypermissions, true);
}
// Prevent serving of incomplete file from concurrent request,
// the rename() should be more atomic than copy().
ignore_user_abort(true);
if (@copy($imagefile, $cacheimage.'.tmp')) {
rename($cacheimage.'.tmp', $cacheimage);
@chmod($cacheimage, $CFG->filepermissions);
@unlink($cacheimage.'.tmp'); // just in case anything fails
}
return $cacheimage;
}