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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   * Contains an abstract base class definition for curl security helpers.
  19   *
  20   * @package   core
  21   * @copyright 2016 Jake Dallimore
  22   * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  23   * @author    Jake Dallimore <jrhdallimore@gmail.com>
  24   */
  25  
  26  namespace core\files;
  27  
  28  defined('MOODLE_INTERNAL') || exit();
  29  
  30  /**
  31   * Security helper for the curl class.
  32   *
  33   * This class is intended as a base class for all curl security helpers. A curl security helper should provide a means to check
  34   * a URL to determine whether curl should be allowed to request its content. It must also be able to return a simple string to
  35   * explain that the URL is blocked, e.g. 'This URL is blocked'.
  36   *
  37   * Curl security helpers are currently used by the 'curl' wrapper class in lib/filelib.php.
  38   *
  39   * This class depends on:
  40   *  - nothing.
  41   *
  42   * @package   core
  43   * @copyright 2016 Jake Dallimore
  44   * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  45   * @author    Jake Dallimore <jrhdallimore@gmail.com>
  46   */
  47  abstract class curl_security_helper_base {
  48  
  49      /**
  50       * Check whether the input url should be blocked or not.
  51       *
  52       * @param string $url the url to check.
  53       * @return bool true if the url is deemed to be blocked, false otherwise.
  54       */
  55      abstract public function url_is_blocked($url);
  56  
  57      /**
  58       * Returns a string, explaining that a URL is blocked.
  59       *
  60       * @return string the lang string indicating that the url has been blocked.
  61       */
  62      abstract public function get_blocked_url_string();
  63  }