Proyectos de Subversion Moodle

<?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 (!min_is_revision_valid_and_current($rev)) {

    // If the rev is invalid, normalise it to -1 to disable all caching.

    $rev = -1;

}

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;

}