public IActionResult AddNumbers(string number1, string number2) { //Add values to a list string List <string> numberList = new string[] { number1, number2 }.ToList(); //Validating string list var errorMsg = numberValidator.ValidateStrings(numberList); //Return bad request if error is detected if (!string.IsNullOrEmpty(errorMsg)) { ModelState.AddModelError("Validation Error", errorMsg); logActivityService.LogActivity($"Timestamp= {DateTime.Now.ToString()}, number1={number1} , number2={number2} , ERROR_MSG = {errorMsg}"); return(BadRequest(ModelState)); } ICalculateNumbers calculateNumbers = new CalculateNumbers(); //Calculate total sum of numbers calculateNumbers.AddNumbers(number1, number2); //Create DTO for serialization var numbers = new NumbersSumDto() { Value1 = number1, Value2 = number2, TotalSum = calculateNumbers.Result }; //Creating error log logActivityService.LogActivity($"Timestamp= {DateTime.Now.ToString()}, number1={number1} , number2={number2} , result={numbers.TotalSum}"); return(Ok(numbers)); }