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Differences Between: [Versions 400 and 402] [Versions 401 and 402] [Versions 402 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  namespace mod_bigbluebuttonbn\local\proxy;
  18  
  19  use mod_bigbluebuttonbn\local\config;
  20  use mod_bigbluebuttonbn\local\exceptions\bigbluebutton_exception;
  21  use mod_bigbluebuttonbn\local\exceptions\server_not_available_exception;
  22  use mod_bigbluebuttonbn\plugin;
  23  use moodle_url;
  24  
  25  /**
  26   * The abstract proxy base class.
  27   *
  28   * This class provides common and shared functions used when interacting with
  29   * the BigBlueButton API server.
  30   *
  31   * @package   mod_bigbluebuttonbn
  32   * @copyright 2010 onwards, Blindside Networks Inc
  33   * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  34   * @author    Jesus Federico  (jesus [at] blindsidenetworks [dt] com)
  35   */
  36  abstract class proxy_base {
  37  
  38      /**
  39       * Sometimes the server sends back some error and errorKeys that
  40       * can be converted to Moodle error messages
  41       */
  42      const BBB_TO_MOODLE_ERROR_CODE = [
  43          'checksumError' => 'index_error_checksum',
  44          'notFound' => 'general_error_not_found',
  45          'maxConcurrent' => 'view_error_max_concurrent',
  46      ];
  47  
  48      /**
  49       * Returns the right URL for the action specified.
  50       *
  51       * @param string $action
  52       * @param array $data
  53       * @param array $metadata
  54       * @return string
  55       */
  56      protected static function action_url(string $action = '', array $data = [], array $metadata = []): string {
  57          $baseurl = self::sanitized_url() . $action . '?';
  58          $metadata = array_combine(array_map(function($k) {
  59              return 'meta_' . $k;
  60          }, array_keys($metadata)), $metadata);
  61  
  62          $params = http_build_query($data + $metadata, '', '&');
  63          $checksum = self::get_checksum($action, $params);
  64          return $baseurl . $params . '&checksum=' . $checksum;
  65      }
  66  
  67      /**
  68       * Makes sure the url used doesn't is in the format required.
  69       *
  70       * @return string
  71       */
  72      protected static function sanitized_url(): string {
  73          $serverurl = trim(config::get('server_url'));
  74          if (PHPUNIT_TEST) {
  75              $serverurl = (new moodle_url(TEST_MOD_BIGBLUEBUTTONBN_MOCK_SERVER))->out(false);
  76          }
  77          if (substr($serverurl, -1) == '/') {
  78              $serverurl = rtrim($serverurl, '/');
  79          }
  80          if (substr($serverurl, -4) == '/api') {
  81              $serverurl = rtrim($serverurl, '/api');
  82          }
  83          return $serverurl . '/api/';
  84      }
  85  
  86      /**
  87       * Makes sure the shared_secret used doesn't have trailing white characters.
  88       *
  89       * @return string
  90       */
  91      protected static function sanitized_secret(): string {
  92          return trim(config::get('shared_secret'));
  93      }
  94  
  95      /**
  96       * Throw an exception if there is a problem in the returned XML value
  97       *
  98       * @param \SimpleXMLElement|bool $xml
  99       * @param array|null $additionaldetails
 100       * @throws bigbluebutton_exception
 101       * @throws server_not_available_exception
 102       */
 103      protected static function assert_returned_xml($xml, ?array $additionaldetails = null): void {
 104          $messagekey = '';
 105          if (!empty($xml)) {
 106              $messagekey = (string) ($xml->messageKey ?? '');
 107          }
 108          if (empty($xml) || static::is_known_server_unavailable_errorcode($messagekey)) {
 109              $errorcode = self::get_errorcode_from_xml_messagekey($messagekey);
 110              throw new server_not_available_exception(
 111                  $errorcode,
 112                  plugin::COMPONENT,
 113                  (new moodle_url('/admin/settings.php?section=modsettingbigbluebuttonbn'))->out(),
 114              );
 115          }
 116          // If it is a checksum error, this is equivalent to the server not being available.
 117          // So we treat it the same way as if there is not answer.
 118          if (is_bool($xml) && $xml) {
 119              // Nothing to do here, this might be a post returning that everything went well.
 120              return;
 121          }
 122          if ((string) $xml->returncode == 'FAILED') {
 123              $errorcode = self::get_errorcode_from_xml_messagekey($messagekey);
 124              if (!$additionaldetails) {
 125                  $additionaldetails = [];
 126              }
 127              $additionaldetails['xmlmessage'] = (string) $xml->message ?? '';
 128  
 129              throw new bigbluebutton_exception($errorcode, json_encode($additionaldetails));
 130          }
 131      }
 132  
 133      /**
 134       * Get Moodle error code from returned Message Key
 135       *
 136       * @param string $messagekey
 137       * @return string
 138       */
 139      private static function get_errorcode_from_xml_messagekey(string $messagekey): string {
 140          $errorcode = 'general_error_no_answer';
 141          if ($messagekey) {
 142              $errorcode = self::BBB_TO_MOODLE_ERROR_CODE[$messagekey] ?? $errorcode;
 143          }
 144          return $errorcode;
 145      }
 146  
 147      /**
 148       * Get Moodle error code from returned Message Key
 149       *
 150       * @param string $messagekey
 151       * @return string
 152       */
 153      private static function is_known_server_unavailable_errorcode(string $messagekey): string {
 154          // For now, only checksumError is supposed to mean that the server is unavailable.
 155          // Other errors are recoverable.
 156          return in_array($messagekey, ['checksumError']);
 157      }
 158  
 159      /**
 160       * Fetch the XML from an endpoint and test for success.
 161       *
 162       * If the result could not be loaded, or the returncode was not 'SUCCESS', a null value is returned.
 163       *
 164       * @param string $action
 165       * @param array $data
 166       * @param array $metadata
 167       * @return null|bool|\SimpleXMLElement
 168       */
 169      protected static function fetch_endpoint_xml(
 170          string $action,
 171          array $data = [],
 172          array $metadata = []
 173      ) {
 174          if (PHPUNIT_TEST && !defined('TEST_MOD_BIGBLUEBUTTONBN_MOCK_SERVER')) {
 175              return true; // In case we still use fetch and mock server is not defined, this prevents
 176              // an error. This can happen if a function from lib.php is called in test from other modules
 177              // for example.
 178          }
 179          $curl = new curl();
 180          return $curl->get(self::action_url($action, $data, $metadata));
 181      }
 182  
 183      /**
 184       * Get checksum
 185       *
 186       * @param string $action
 187       * @param string $params
 188       * @return string
 189       */
 190      public static function get_checksum(string $action, string $params): string {
 191          return hash(config::get('checksum_algorithm'), $action . $params . self::sanitized_secret());
 192      }
 193  }