http://tech.recruit-mp.co.jp/server-side/post-2540/ これ

doAction6.scala

def doAction6 = Action { implicit req =>
  (for {
    _    <- authorizeHeaders(req.headers) \/> BadRequest("Unauthorized request")
    json <- req.body.asJson               \/> BadRequest("Wrong POST body")
    user <- validateJson(json)            \/> BadRequest("Invalid JSON")
  } yield {
    doSomething(user)
    Ok("Success")
  }).merge
}