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Differences Between: [Versions 310 and 403] [Versions 311 and 403] [Versions 39 and 403] [Versions 400 and 403] [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  namespace core_xapi;
  18  
  19  use core_xapi\local\state;
  20  use core_xapi\local\statement;
  21  use core_xapi\xapi_exception;
  22  
  23  /**
  24   * Class handler handles basic xAPI statements and states.
  25   *
  26   * @package    core_xapi
  27   * @since      Moodle 3.9
  28   * @copyright  2020 Ferran Recio
  29   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  30   */
  31  abstract class handler {
  32  
  33      /** @var string component name in frankenstyle. */
  34      protected $component;
  35  
  36      /** @var state_store the state_store instance. */
  37      protected $statestore;
  38  
  39      /**
  40       * Constructor for a xAPI handler base class.
  41       *
  42       * @param string $component the component name
  43       */
  44      final protected function __construct(string $component) {
  45          $this->component = $component;
  46          $this->statestore = $this->get_state_store();
  47      }
  48  
  49      /**
  50       * Returns the xAPI handler of a specific component.
  51       *
  52       * @param string $component the component name in frankenstyle.
  53       * @return handler|null a handler object or null if none found.
  54       * @throws xapi_exception
  55       */
  56      final public static function create(string $component): self {
  57          if (self::supports_xapi($component)) {
  58              $classname = "\\$component\\xapi\\handler";
  59              return new $classname($component);
  60          }
  61          throw new xapi_exception('Unknown handler');
  62      }
  63  
  64      /**
  65       * Whether a component supports (and implements) xAPI.
  66       *
  67       * @param string $component the component name in frankenstyle.
  68       * @return bool true if the given component implements xAPI handler; false otherwise.
  69       */
  70      final public static function supports_xapi(string $component): bool {
  71          $classname = "\\$component\\xapi\\handler";
  72          return class_exists($classname);
  73      }
  74  
  75      /**
  76       * Convert a statement object into a Moodle xAPI Event.
  77       *
  78       * If a statement is accepted by validate_statement the component must provide a event
  79       * to handle that statement, otherwise the statement will be rejected.
  80       *
  81       * Note: this method must be overridden by the plugins which want to use xAPI.
  82       *
  83       * @param statement $statement
  84       * @return \core\event\base|null a Moodle event to trigger
  85       */
  86      abstract public function statement_to_event(statement $statement): ?\core\event\base;
  87  
  88      /**
  89       * Return true if group actor is enabled.
  90       *
  91       * Note: this method must be overridden by the plugins which want to
  92       * use groups in statements.
  93       *
  94       * @return bool
  95       */
  96      public function supports_group_actors(): bool {
  97          return false;
  98      }
  99  
 100      /**
 101       * Process a bunch of statements sended to a specific component.
 102       *
 103       * @param statement[] $statements an array with all statement to process.
 104       * @return int[] return an specifying what statements are being stored.
 105       */
 106      public function process_statements(array $statements): array {
 107          $result = [];
 108          foreach ($statements as $key => $statement) {
 109              try {
 110                  // Ask the plugin to convert into an event.
 111                  $event = $this->statement_to_event($statement);
 112                  if ($event) {
 113                      $event->trigger();
 114                      $result[$key] = true;
 115                  } else {
 116                      $result[$key] = false;
 117                  }
 118              } catch (\Exception $e) {
 119                  $result[$key] = false;
 120              }
 121          }
 122          return $result;
 123      }
 124  
 125      /**
 126       * Validate a xAPI state.
 127       *
 128       * Check if the state is valid for this handler.
 129       *
 130       * This method is used also for the state get requests so the validation
 131       * cannot rely on having state data.
 132       *
 133       * Note: this method must be overridden by the plugins which want to use xAPI states.
 134       *
 135       * @param state $state
 136       * @return bool if the state is valid or not
 137       */
 138      abstract protected function validate_state(state $state): bool;
 139  
 140      /**
 141       * Process a state save request.
 142       *
 143       * @param state $state the state object
 144       * @return bool if the state can be saved
 145       */
 146      public function save_state(state $state): bool {
 147          if (!$this->validate_state($state)) {
 148              throw new xapi_exception('The state is not accepted, so it cannot be saved');
 149          }
 150          return $this->statestore->put($state);
 151      }
 152  
 153      /**
 154       * Process a state save request.
 155       *
 156       * @param state $state the state object
 157       * @return state|null the resulting loaded state
 158       */
 159      public function load_state(state $state): ?state {
 160          if (!$this->validate_state($state)) {
 161              throw new xapi_exception('The state is not accepted, so it cannot be loaded');
 162          }
 163          $state = $this->statestore->get($state);
 164          return $state;
 165      }
 166  
 167      /**
 168       * Process a state delete request.
 169       *
 170       * @param state $state the state object
 171       * @return bool if the deletion is successful
 172       */
 173      public function delete_state(state $state): bool {
 174          if (!$this->validate_state($state)) {
 175              throw new xapi_exception('The state is not accepted, so it cannot be deleted');
 176          }
 177          return $this->statestore->delete($state);
 178      }
 179  
 180      /**
 181       * Delete all states from this component.
 182       *
 183       * @param string|null $itemid
 184       * @param int|null $userid
 185       * @param string|null $stateid
 186       * @param string|null $registration
 187       */
 188      public function wipe_states(
 189          ?string $itemid = null,
 190          ?int $userid = null,
 191          ?string $stateid = null,
 192          ?string $registration = null
 193      ): void {
 194          $this->statestore->wipe($itemid, $userid, $stateid, $registration);
 195      }
 196  
 197      /**
 198       * Reset all states from this component.
 199       *
 200       * @param string|null $itemid
 201       * @param int|null $userid
 202       * @param string|null $stateid
 203       * @param string|null $registration
 204       */
 205      public function reset_states(
 206          ?string $itemid = null,
 207          ?int $userid = null,
 208          ?string $stateid = null,
 209          ?string $registration = null
 210      ): void {
 211          $this->statestore->reset($itemid, $userid, $stateid, $registration);
 212      }
 213  
 214      /**
 215       * Return a valor state store for this component.
 216       *
 217       * Plugins may override this method is they want to use a different
 218       * state store class.
 219       * @return state_store the store to use to get/put/delete states.
 220       */
 221      public function get_state_store(): state_store {
 222          return new state_store($this->component);
 223      }
 224  }