dd_action('rest_api_init', function(){
  register_rest_route('qhht/v1','who',[
    'methods' => 'GET',
    'permission_callback' => '__return_true',
    'callback' => function(){
      $u = wp_get_current_user();
      return [
        'user' => $u ? $u->user_login : null,
        'caps' => array_keys((array)$u->allcaps),
      ];
    }
  ]);
});




?>