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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 serving optimised JS and WASM for ogv.js.
  19   *
  20   * @package media_videojs
  21   * @copyright 2021 Huong Nguyen <huongnv13@gmail.com>
  22   * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  23   */
  24  
  25  // Disable moodle specific debug messages and any errors in output,
  26  // comment out when debugging or better look into error log!
  27  define('NO_DEBUG_DISPLAY', true);
  28  
  29  // We need just the values from config.php and minlib.php.
  30  define('ABORT_AFTER_CONFIG', true);
  31  require_once('../../../config.php'); // This stops immediately at the beginning of lib/setup.php.
  32  require_once($CFG->dirroot . '/lib/jslib.php');
  33  require_once($CFG->dirroot . '/lib/wasmlib.php');
  34  
  35  $slashargument = min_get_slash_argument();
  36  if (!$slashargument) {
  37      // The above call to min_get_slash_argument should always work.
  38      die('Invalid request');
  39  }
  40  
  41  $slashargument = ltrim($slashargument, '/');
  42  if (substr_count($slashargument, '/') < 1) {
  43      header('HTTP/1.0 404 not found');
  44      die('Slash argument must contain both a revision and a file path');
  45  }
  46  
  47  // Get all the library files (js and wasm) of the OGV.
  48  $basepath = $CFG->dirroot . '/media/player/videojs/ogvjs/';
  49  $jsfiles = [];
  50  $files = glob("{$basepath}*.{js,wasm}", GLOB_BRACE);
  51  foreach ($files as $file) {
  52      $jsfiles[] = basename($file);
  53  }
  54  
  55  // Split into revision and module name.
  56  list($rev, $file) = explode('/', $slashargument, 2);
  57  $rev  = min_clean_param($rev, 'INT');
  58  $file = min_clean_param($file, 'SAFEPATH');
  59  
  60  if (empty($jsfiles) || !in_array($file, $jsfiles)) {
  61      // We can't find the requested file.
  62      header('HTTP/1.0 404 not found');
  63      exit(0);
  64  }
  65  
  66  // Check if the requesting file is Javascript or Web Assembly.
  67  $iswasm = media_videojs_ogvloader_is_wasm_file($file);
  68  
  69  // Use the caching only for meaningful revision numbers which prevents future cache poisoning.
  70  if ($rev > 0 and $rev < (time() + 60 * 60)) {
  71      // We are lazy loading a single file - so include the filename in the etag.
  72      $etag = sha1($rev . '/' . $file);
  73      $candidate = $CFG->localcachedir . '/ogvloader/' . $etag;
  74  
  75      if (file_exists($candidate)) {
  76          // Cache exist.
  77          if (!empty($_SERVER['HTTP_IF_NONE_MATCH']) || !empty($_SERVER['HTTP_IF_MODIFIED_SINCE'])) {
  78              // We do not actually need to verify the etag value because our files
  79              // never change in cache because we increment the rev parameter.
  80              media_videojs_ogvloader_send_unmodified($iswasm, $candidate, $etag);
  81          }
  82          media_videojs_ogvloader_send_cached($iswasm, $candidate, $etag);
  83          exit(0);
  84      } else {
  85          // Cache does not exist. Create one.
  86          $filecontent = file_get_contents($basepath . $file);
  87          if ($filecontent === false) {
  88              error_log('Failed to load the library ' . $file);
  89              $filecontent = "/* Failed to load library file {$file}. */\n";
  90          }
  91  
  92          $filecontent = media_videojs_ogvloader_add_module_module_name_if_necessary($iswasm, $filecontent);
  93          media_videojs_ogvloader_write_cache_file_content($iswasm, $candidate, $filecontent);
  94          // Verify nothing failed in cache file creation.
  95          clearstatcache();
  96          if (file_exists($candidate)) {
  97              media_videojs_ogvloader_send_cached($iswasm, $candidate, $etag);
  98              exit(0);
  99          }
 100      }
 101  }
 102  
 103  // If we've made it here then we're in "dev mode" where everything is lazy loaded.
 104  // So all files will be served one at a time.
 105  $filecontent = file_get_contents($basepath . $file);
 106  $filecontent = rtrim($filecontent);
 107  $filecontent = media_videojs_ogvloader_add_module_module_name_if_necessary($iswasm, $filecontent);
 108  media_videojs_ogvloader_send_uncached($iswasm, $filecontent);
 109  
 110  /**
 111   * Check the given file is a Web Assembly file or not
 112   *
 113   * @param string $filename File name to check
 114   * @return bool Whether the file is Web Assembly or not
 115   */
 116  function media_videojs_ogvloader_is_wasm_file(string $filename): bool {
 117      $ext = pathinfo($filename, PATHINFO_EXTENSION);
 118      return $ext == 'wasm';
 119  }
 120  
 121  /**
 122   * Add Moodle module name to the Javascript module if necessary
 123   *
 124   * @param bool $iswasm Whether the file is Web Assembly or not
 125   * @param string $content File content
 126   * @return string
 127   */
 128  function media_videojs_ogvloader_add_module_module_name_if_necessary(bool $iswasm, string $content): string {
 129      if (!$iswasm && preg_match('/define\(\s*(\[|function)/', $content)) {
 130          // If the JavaScript module has been defined without specifying a name then we'll
 131          // add the Moodle module name now.
 132          $replace = 'define(\'media_videojs/video-lazy\', ';
 133          $search = 'define(';
 134          // Replace only the first occurrence.
 135          $content = implode($replace, explode($search, $content, 2));
 136      }
 137  
 138      return $content;
 139  }
 140  
 141  /**
 142   * Create cache file content
 143   *
 144   * @param bool $iswasm Whether the file is Web Assembly or not
 145   * @param string $candidate Full file path to cache file
 146   * @param string $filecontent File content
 147   */
 148  function media_videojs_ogvloader_write_cache_file_content(bool $iswasm, string $candidate, string $filecontent): void {
 149      $iswasm ? wasm_write_cache_file_content($candidate, $filecontent) : js_write_cache_file_content($candidate, $filecontent);
 150  }
 151  
 152  /**
 153   * Send file content with as much caching as possible
 154   *
 155   * @param bool $iswasm Whether the file is Web Assembly or not
 156   * @param string $candidate Full file path to cache file
 157   * @param string $etag Etag
 158   */
 159  function media_videojs_ogvloader_send_cached(bool $iswasm, string $candidate, string $etag): void {
 160      $iswasm ? wasm_send_cached($candidate, $etag, 'ogvloader.php') : js_send_cached($candidate, $etag, 'ogvloader.php');
 161  }
 162  
 163  /**
 164   * Send file without any caching
 165   *
 166   * @param bool $iswasm Whether the file is Web Assembly or not
 167   * @param string $ilecontent File content
 168   */
 169  function media_videojs_ogvloader_send_uncached(bool $iswasm, string $ilecontent): void {
 170      $iswasm ? wasm_send_uncached($ilecontent, 'ogvloader.php') : js_send_uncached($ilecontent, 'ogvloader.php');
 171  }
 172  
 173  /**
 174   * Send the file not modified headers
 175   *
 176   * @param bool $iswasm Whether the file is Web Assembly or not
 177   * @param int $candidate Full file path to cache file
 178   * @param string $etag Etag
 179   */
 180  function media_videojs_ogvloader_send_unmodified(bool $iswasm, int $candidate, string $etag): void {
 181      $iswasm ? wasm_send_unmodified(filemtime($candidate), $etag) : js_send_unmodified(filemtime($candidate), $etag);
 182  }