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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 contains CSS file serving functions.
  19   *
  20   * NOTE: these functions are not expected to be used from any addons.
  21   *
  22   * @package core
  23   * @copyright 2012 Sam Hemelryk
  24   * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  25   */
  26  
  27  defined('MOODLE_INTERNAL') || die();
  28  
  29  if (!defined('THEME_DESIGNER_CACHE_LIFETIME')) {
  30      // This can be also set in config.php file,
  31      // it needs to be higher than the time it takes to generate all CSS content.
  32      define('THEME_DESIGNER_CACHE_LIFETIME', 10);
  33  }
  34  
  35  /**
  36   * Stores CSS in a file at the given path.
  37   *
  38   * This function either succeeds or throws an exception.
  39   *
  40   * @param theme_config $theme The theme that the CSS belongs to.
  41   * @param string $csspath The path to store the CSS at.
  42   * @param string $csscontent the complete CSS in one string.
  43   */
  44  function css_store_css(theme_config $theme, $csspath, $csscontent) {
  45      global $CFG;
  46  
  47      clearstatcache();
  48      if (!file_exists(dirname($csspath))) {
  49          @mkdir(dirname($csspath), $CFG->directorypermissions, true);
  50      }
  51  
  52      // Prevent serving of incomplete file from concurrent request,
  53      // the rename() should be more atomic than fwrite().
  54      ignore_user_abort(true);
  55  
  56      // First up write out the single file for all those using decent browsers.
  57      css_write_file($csspath, $csscontent);
  58  
  59      ignore_user_abort(false);
  60      if (connection_aborted()) {
  61          die;
  62      }
  63  }
  64  
  65  /**
  66   * Writes a CSS file.
  67   *
  68   * @param string $filename
  69   * @param string $content
  70   */
  71  function css_write_file($filename, $content) {
  72      global $CFG;
  73      if ($fp = fopen($filename.'.tmp', 'xb')) {
  74          fwrite($fp, $content);
  75          fclose($fp);
  76          rename($filename.'.tmp', $filename);
  77          @chmod($filename, $CFG->filepermissions);
  78          @unlink($filename.'.tmp'); // Just in case anything fails.
  79      }
  80  }
  81  
  82  /**
  83   * Sends a cached CSS file
  84   *
  85   * This function sends the cached CSS file. Remember it is generated on the first
  86   * request, then optimised/minified, and finally cached for serving.
  87   *
  88   * @param string $csspath The path to the CSS file we want to serve.
  89   * @param string $etag The revision to make sure we utilise any caches.
  90   */
  91  function css_send_cached_css($csspath, $etag) {
  92      // 90 days only - based on Moodle point release cadence being every 3 months.
  93      $lifetime = 60 * 60 * 24 * 90;
  94  
  95      header('Etag: "'.$etag.'"');
  96      header('Content-Disposition: inline; filename="styles.php"');
  97      header('Last-Modified: '. gmdate('D, d M Y H:i:s', filemtime($csspath)) .' GMT');
  98      header('Expires: '. gmdate('D, d M Y H:i:s', time() + $lifetime) .' GMT');
  99      header('Pragma: ');
 100      header('Cache-Control: public, max-age='.$lifetime.', immutable');
 101      header('Accept-Ranges: none');
 102      header('Content-Type: text/css; charset=utf-8');
 103      if (!min_enable_zlib_compression()) {
 104          header('Content-Length: '.filesize($csspath));
 105      }
 106  
 107      readfile($csspath);
 108      die;
 109  }
 110  
 111  /**
 112   * Sends a cached CSS content
 113   *
 114   * @param string $csscontent The actual CSS markup.
 115   * @param string $etag The revision to make sure we utilise any caches.
 116   */
 117  function css_send_cached_css_content($csscontent, $etag) {
 118      // 90 days only - based on Moodle point release cadence being every 3 months.
 119      $lifetime = 60 * 60 * 24 * 90;
 120  
 121      header('Etag: "'.$etag.'"');
 122      header('Content-Disposition: inline; filename="styles.php"');
 123      header('Last-Modified: '. gmdate('D, d M Y H:i:s', time()) .' GMT');
 124      header('Expires: '. gmdate('D, d M Y H:i:s', time() + $lifetime) .' GMT');
 125      header('Pragma: ');
 126      header('Cache-Control: public, max-age='.$lifetime.', immutable');
 127      header('Accept-Ranges: none');
 128      header('Content-Type: text/css; charset=utf-8');
 129      if (!min_enable_zlib_compression()) {
 130          header('Content-Length: '.strlen($csscontent));
 131      }
 132  
 133      echo($csscontent);
 134      die;
 135  }
 136  
 137  /**
 138   * Sends CSS directly and disables all caching.
 139   * The Content-Length of the body is also included, but the script is not ended.
 140   *
 141   * @param string $css The CSS content to send
 142   */
 143  function css_send_temporary_css($css) {
 144      header('Cache-Control: no-cache, no-store, must-revalidate');
 145      header('Pragma: no-cache');
 146      header('Expires: 0');
 147      header('Content-Disposition: inline; filename="styles_debug.php"');
 148      header('Last-Modified: '. gmdate('D, d M Y H:i:s', time()) .' GMT');
 149      header('Accept-Ranges: none');
 150      header('Content-Type: text/css; charset=utf-8');
 151      header('Content-Length: ' . strlen($css));
 152  
 153      echo $css;
 154  }
 155  
 156  /**
 157   * Sends CSS directly without caching it.
 158   *
 159   * This function takes a raw CSS string, optimises it if required, and then
 160   * serves it.
 161   * Turning both themedesignermode and CSS optimiser on at the same time is awful
 162   * for performance because of the optimiser running here. However it was done so
 163   * that theme designers could utilise the optimised output during development to
 164   * help them optimise their CSS... not that they should write lazy CSS.
 165   *
 166   * @param string $css
 167   */
 168  function css_send_uncached_css($css) {
 169      header('Content-Disposition: inline; filename="styles_debug.php"');
 170      header('Last-Modified: '. gmdate('D, d M Y H:i:s', time()) .' GMT');
 171      header('Expires: '. gmdate('D, d M Y H:i:s', time() + THEME_DESIGNER_CACHE_LIFETIME) .' GMT');
 172      header('Pragma: ');
 173      header('Accept-Ranges: none');
 174      header('Content-Type: text/css; charset=utf-8');
 175  
 176      if (is_array($css)) {
 177          $css = implode("\n\n", $css);
 178      }
 179      echo $css;
 180      die;
 181  }
 182  
 183  /**
 184   * Send file not modified headers
 185   *
 186   * @param int $lastmodified
 187   * @param string $etag
 188   */
 189  function css_send_unmodified($lastmodified, $etag) {
 190      // 90 days only - based on Moodle point release cadence being every 3 months.
 191      $lifetime = 60 * 60 * 24 * 90;
 192      header('HTTP/1.1 304 Not Modified');
 193      header('Expires: '. gmdate('D, d M Y H:i:s', time() + $lifetime) .' GMT');
 194      header('Cache-Control: public, max-age='.$lifetime);
 195      header('Content-Type: text/css; charset=utf-8');
 196      header('Etag: "'.$etag.'"');
 197      if ($lastmodified) {
 198          header('Last-Modified: '. gmdate('D, d M Y H:i:s', $lastmodified) .' GMT');
 199      }
 200      die;
 201  }
 202  
 203  /**
 204   * Sends a 404 message about CSS not being found.
 205   */
 206  function css_send_css_not_found() {
 207      header('HTTP/1.0 404 not found');
 208      die('CSS was not found, sorry.');
 209  }