/**
  * 获取权限
  * @return string|void
  */
 public function actionGet()
 {
     $id = $this->get('id', 0);
     if ($id) {
         $perm = Permission::findByCache($id);
         if ($perm) {
             $this->setResponseData('data', $perm);
         } else {
             $this->setError(Module::t('error.perm.notexists'));
         }
     } else {
         $this->setError(Module::t('error.perm.notexists'));
     }
 }