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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   * This is the external API for generic xAPI handling.
  19   *
  20   * @package    core_xapi
  21   * @since      Moodle 3.9
  22   * @copyright  2020 Ferran Recio
  23   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  24   */
  25  
  26  namespace core_xapi\external;
  27  
  28  use core_xapi\local\statement;
  29  use core_xapi\handler;
  30  use core_xapi\xapi_exception;
  31  use external_api;
  32  use external_function_parameters;
  33  use external_value;
  34  use external_single_structure;
  35  use external_multiple_structure;
  36  use external_warnings;
  37  use core_component;
  38  
  39  defined('MOODLE_INTERNAL') || die();
  40  
  41  require_once($CFG->libdir .'/externallib.php');
  42  
  43  /**
  44   * This is the external API for generic xAPI handling.
  45   *
  46   * @copyright  2020 Ferran Recio
  47   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  48   */
  49  class post_statement extends external_api {
  50  
  51      /**
  52       * Parameters for execute
  53       *
  54       * @return external_function_parameters
  55       */
  56      public static function execute_parameters() {
  57          return new external_function_parameters(
  58              [
  59                  'component' => new external_value(PARAM_COMPONENT, 'Component name', VALUE_REQUIRED),
  60                  'requestjson' => new external_value(PARAM_RAW, 'json object with all the statements to post', VALUE_REQUIRED)
  61              ]
  62          );
  63      }
  64  
  65      /**
  66       * Process a statement post request.
  67       *
  68       * @param string $component component name (frankenstyle)
  69       * @param string $requestjson json object with all the statements to post
  70       * @return bool[] storing acceptance of every statement
  71       */
  72      public static function execute(string $component, string $requestjson): array {
  73  
  74          $params = self::validate_parameters(self::execute_parameters(), array(
  75              'component' => $component,
  76              'requestjson' => $requestjson,
  77          ));
  78          $component = $params['component'];
  79          $requestjson = $params['requestjson'];
  80  
  81          static::validate_component($component);
  82  
  83          $handler = handler::create($component);
  84  
  85          $statements = self::get_statements_from_json($requestjson);
  86  
  87          if (!self::check_statements_users($statements, $handler)) {
  88              throw new xapi_exception('Statements actor is not the current user');
  89          }
  90  
  91          $result = $handler->process_statements($statements);
  92  
  93          // In case no statement is processed, an error must be returned.
  94          if (count(array_filter($result)) == 0) {
  95              throw new xapi_exception('No statement can be processed.');
  96          }
  97          return $result;
  98      }
  99  
 100      /**
 101       * Return for execute.
 102       */
 103      public static function execute_returns() {
 104          return new external_multiple_structure(
 105              new external_value(PARAM_BOOL, 'If the statement is accepted'),
 106              'List of statements storing acceptance results'
 107          );
 108      }
 109  
 110      /**
 111       * Check component name.
 112       *
 113       * Note: this function is separated mainly for testing purposes to
 114       * be overridden to fake components.
 115       *
 116       * @throws xapi_exception if component is not available
 117       * @param string $component component name
 118       */
 119      protected static function validate_component(string $component): void {
 120          // Check that $component is a real component name.
 121          $dir = core_component::get_component_directory($component);
 122          if (!$dir) {
 123              throw new xapi_exception("Component $component not available.");
 124          }
 125      }
 126  
 127      /**
 128       * Convert mulitple types of statement request into an array of statements.
 129       *
 130       * @throws xapi_exception if JSON cannot be parsed
 131       * @param string $requestjson json encoded statements structure
 132       * @return statement[] array of statements
 133       */
 134      private static function get_statements_from_json(string $requestjson): array {
 135          $request = json_decode($requestjson);
 136          if ($request === null) {
 137              throw new xapi_exception('JSON error: '.json_last_error_msg());
 138          }
 139          $result = [];
 140          if (is_array($request)) {
 141              foreach ($request as $data) {
 142                  $result[] = statement::create_from_data($data);
 143              }
 144          } else {
 145              $result[] = statement::create_from_data($request);
 146          }
 147          if (empty($result)) {
 148              throw new xapi_exception('No statements detected');
 149          }
 150          return $result;
 151      }
 152  
 153      /**
 154       * Check that $USER is actor in all statements.
 155       *
 156       * @param statement[] $statements array of statements
 157       * @param handler $handler specific xAPI handler
 158       * @return bool if $USER is actor in all statements
 159       */
 160      private static function check_statements_users(array $statements, handler $handler): bool {
 161          global $USER;
 162  
 163          foreach ($statements as $statement) {
 164              if ($handler->supports_group_actors()) {
 165                  $users = $statement->get_all_users();
 166                  if (!isset($users[$USER->id])) {
 167                      return false;
 168                  }
 169              } else {
 170                  $user = $statement->get_user();
 171                  if ($user->id != $USER->id) {
 172                      return false;
 173                  }
 174              }
 175          }
 176          return true;
 177      }
 178  }