yii\web\IdentityInterface::getId PHP Метод

    public function getId();

 /**
  * Sends an identity cookie.
  * This method is used when [[enableAutoLogin]] is true.
  * It saves [[id]], [[IdentityInterface::getAuthKey()|auth key]], and the duration of cookie-based login
  * information in the cookie.
  * @param IdentityInterface $identity
  * @param integer $duration number of seconds that the user can remain in logged-in status.
  * @see loginByCookie()
  */
 protected function sendIdentityCookie($identity, $duration)
 {
     $cookie = new Cookie($this->identityCookie);
     $cookie->value = json_encode([$identity->getId(), $identity->getAuthKey(), $this->getRole(), $duration], JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE);
     $cookie->expire = time() + $duration;
     Yii::$app->getResponse()->getCookies()->add($cookie);
 }