laravel 5 Decode Post method url

data=%7B%22password%22%3A%221234%22%2C%22username%22%3A%22user1234%22%7D&

i have this type url from post request it decode look like this

data={"password":"1234","username":"user1234"}&

in my case im try to decoe with larave, but it not work propery,how can i do it

this is my sample code

function login(Request $request)
    {
 $requestData =$request->request->get('data');

        $data = json_decode($requestData, true);

        $username = $data['username'];
        $password = $data['password'];

return new JsonResponse($username );
}

via Chebli Mohamed