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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   * Implementaton of the quizaccess_safebrowser plugin.
  19   *
  20   * @package    quizaccess
  21   * @subpackage safebrowser
  22   * @copyright  2011 The Open University
  23   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  24   */
  25  
  26  
  27  defined('MOODLE_INTERNAL') || die();
  28  
  29  require_once($CFG->dirroot . '/mod/quiz/accessrule/accessrulebase.php');
  30  
  31  
  32  /**
  33   * A rule representing the safe browser check.
  34   *
  35   * @copyright  2009 Oliver Rahs
  36   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  37   */
  38  class quizaccess_safebrowser extends quiz_access_rule_base {
  39  
  40      public static function make(quiz $quizobj, $timenow, $canignoretimelimits) {
  41  
  42          if ($quizobj->get_quiz()->browsersecurity !== 'safebrowser') {
  43              return null;
  44          }
  45  
  46          return new self($quizobj, $timenow);
  47      }
  48  
  49      public function prevent_access() {
  50          if (!$this->check_safe_browser()) {
  51              return get_string('safebrowsererror', 'quizaccess_safebrowser');
  52          } else {
  53              return false;
  54          }
  55      }
  56  
  57      public function description() {
  58          return get_string('safebrowsernotice', 'quizaccess_safebrowser');
  59      }
  60  
  61      public function setup_attempt_page($page) {
  62          $page->set_title($this->quizobj->get_course()->shortname . ': ' . $page->title);
  63          $page->set_cacheable(false);
  64          $page->set_popup_notification_allowed(false); // Prevent message notifications.
  65          $page->set_heading($page->title);
  66          $page->set_pagelayout('secure');
  67      }
  68  
  69      /**
  70       * Checks if browser is safe browser
  71       *
  72       * @return true, if browser is safe browser else false
  73       */
  74      public function check_safe_browser() {
  75          return strpos($_SERVER['HTTP_USER_AGENT'], 'SEB') !== false;
  76      }
  77  
  78      /**
  79       * @return array key => lang string any choices to add to the quiz Browser
  80       *      security settings menu.
  81       */
  82      public static function get_browser_security_choices() {
  83          global $CFG;
  84  
  85          if (empty($CFG->enablesafebrowserintegration)) {
  86              return array();
  87          }
  88  
  89          return array('safebrowser' =>
  90                  get_string('requiresafeexambrowser', 'quizaccess_safebrowser'));
  91      }
  92  }