spray post example

  path("login") {
    post {
      formFields('username, 'password) { (username, password) =>
        val queryResult = (db ? Admin(username, password).find).mapTo[QueryResult]
        onSuccess(queryResult) { qr =>
          qr.rows match {
            case Some(Seq(single: RowData)) =>
              onSuccess(createSession(single)) { session_id =>
                setCookie(HttpCookie(identity_cookie_name, session_id)) {
                  redirect("/admin/index", StatusCodes.SeeOther)
                }
              }
            case _ => complete(StatusCodes.Unauthorized, "用户名或密码错误")
          }
        }
      }
    }
  }