public async Task <ActionResult> GetObservations(WeatherWmo stationId, string fields) { var result = await _service.GetJsonAsync(stationId); var records = result?.GetRecords(); if (!string.IsNullOrEmpty(fields)) { var splitter = ','; var expandos = _service.FilterBy(records, fields.Split(splitter)); var jsonExpandos = JsonConvert.SerializeObject(expandos); return(Ok(jsonExpandos)); } else { var jsonRecords = JsonConvert.SerializeObject(records); return(Ok(jsonRecords)); } }