带有file_get_contents（'php：// input'）的laravel回调url

in vanilla php i would create a callbak url with just

 try
      {
     //response content type application/json
          header("Content-Type:application/json");
            //read incoming request
          $postData = file_get_contents('php://input');
        .......
        ......

but in laravel i'm yet to get a clear explanation on how to achieve the same

ive tried using

 $postData = Request::getContent();

but it returns blank

If you need data in request use (new \Illuminate\Http\Request())->all() or use DI

public function someAction(\Illuminate\Http\Request $request)
{
   dd($request->all());
}