yii 控制器响应处理

//返回响应组件
$res = \YII::$app->response;
//设置返回浏览器状态码
$res->statusCode='404';
//设置http头
$res->headers->add('pragma','no-cache');
$res->headers->set('pragma','no-cache');
$res->headers->remove('pragma');
//跳转
$res->headers->add('Location','www.baidu.com');
$res->redirect('www.baidu.com','302');
//文件下载
$res>headers>add('contentdisposition','www.baidu.com');
 $res->sendFile('./robots.txt');