public HttpResponseMessage AddCar(CarRegistrationDto carRegistrationDto) { string numberPlate = carRegistrationDto.Number_Plate; string make = carRegistrationDto.Make; string model = carRegistrationDto.Model; int year = carRegistrationDto.Year; int numberOfSeats = carRegistrationDto.Number_Of_Seats; string ownerId = carRegistrationDto.Owner_ID; if (!isUserIdEqualToLoggedInUser(ownerId)) { var message = string.Format("Permission denied"); HttpError err = new HttpError(message); return(Request.CreateResponse(HttpStatusCode.Unauthorized, err)); } else { bool success = carBusiness.AddCar(numberPlate, make, model, year, numberOfSeats, ownerId); if (!success) { var message = string.Format(carBusiness.CarRegistrationValidationMessage(numberPlate, make, model, year, numberOfSeats, ownerId)); HttpError err = new HttpError(message); return(Request.CreateResponse(HttpStatusCode.BadRequest, err)); } else { var message = string.Format("Car registered successfully!"); return(Request.CreateResponse(HttpStatusCode.OK, string.Format(message))); } } }