[Summary view]

Differences Between: [Versions 401 and 402] [Versions 401 and 403]

   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   * Helper class.
  19   *
  20   * @package    quizaccess_seb
  21   * @author     Dmitrii Metelkin <dmitriim@catalyst-au.net>
  22   * @copyright  2020 Catalyst IT
  23   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  24   */
  25  
  26  namespace quizaccess_seb;
  27  
  28  
  29  use CFPropertyList\CFPropertyList;
  30  
  31  defined('MOODLE_INTERNAL') || die();
  32  
  33  /**
  34   * Helper class.
  35   *
  36   * @copyright  2020 Catalyst IT
  37   * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  38   */
  39  class helper {
  40      /**
  41       * Get a filler icon for display in the actions column of a table.
  42       *
  43       * @param string $url The URL for the icon.
  44       * @param string $icon The icon identifier.
  45       * @param string $alt The alt text for the icon.
  46       * @param string $iconcomponent The icon component.
  47       * @param array $options Display options.
  48       * @return string
  49       */
  50      public static function format_icon_link($url, $icon, $alt, $iconcomponent = 'moodle', $options = array()) {
  51          global $OUTPUT;
  52  
  53          return $OUTPUT->action_icon(
  54              $url,
  55              new \pix_icon($icon, $alt, $iconcomponent, [
  56                  'title' => $alt,
  57              ]),
  58              null,
  59              $options
  60          );
  61      }
  62  
  63      /**
  64       * Validate seb config string.
  65       *
  66       * @param string $sebconfig
  67       * @return bool
  68       */
  69      public static function is_valid_seb_config(string $sebconfig) : bool {
  70          $result = true;
  71  
  72          set_error_handler(function($errno, $errstr, $errfile, $errline ){
  73              throw new \ErrorException($errstr, $errno, 0, $errfile, $errline);
  74          });
  75  
  76          $plist = new CFPropertyList();
  77          try {
  78              $plist->parse($sebconfig);
  79          } catch (\ErrorException $e) {
  80              $result = false;
  81          } catch (\Exception $e) {
  82              $result = false;
  83          }
  84  
  85          restore_error_handler();
  86  
  87          return $result;
  88      }
  89  
  90      /**
  91       * A helper function to get a list of seb config file headers.
  92       *
  93       * @param int|null $expiretime  Unix timestamp
  94       * @return array
  95       */
  96      public static function get_seb_file_headers(int $expiretime = null) : array {
  97          if (is_null($expiretime)) {
  98              $expiretime = time();
  99          }
 100          $headers = [];
 101          $headers[] = 'Cache-Control: private, max-age=1, no-transform';
 102          $headers[] = 'Expires: '. gmdate('D, d M Y H:i:s', $expiretime) .' GMT';
 103          $headers[] = 'Pragma: no-cache';
 104          $headers[] = 'Content-Disposition: attachment; filename=config.seb';
 105          $headers[] = 'Content-Type: application/seb';
 106  
 107          return $headers;
 108      }
 109  
 110      /**
 111       * Get seb config content for a particular quiz. This method checks caps.
 112       *
 113       * @param string $cmid The course module ID for a quiz with config.
 114       * @return string SEB config string.
 115       */
 116      public static function get_seb_config_content(string $cmid) : string {
 117          // Try and get the course module.
 118          $cm = get_coursemodule_from_id('quiz', $cmid, 0, false, MUST_EXIST);
 119  
 120          // Make sure the user is logged in and has access to the module.
 121          require_login($cm->course, false, $cm);
 122  
 123          // Retrieve the config for quiz.
 124          $config = quiz_settings::get_config_by_quiz_id($cm->instance);
 125          if (empty($config)) {
 126              throw new \moodle_exception('noconfigfound', 'quizaccess_seb', '', $cm->id);
 127          }
 128          return $config;
 129      }
 130  
 131      /**
 132       * Serve a file to browser for download.
 133       *
 134       * @param string $contents Contents of file.
 135       */
 136      public static function send_seb_config_file(string $contents) {
 137          // We can now send the file back to the browser.
 138          foreach (self::get_seb_file_headers() as $header) {
 139              header($header);
 140          }
 141  
 142          echo($contents);
 143      }
 144  
 145  }
 146