public async Task <IList <Rate> > GetRateAsync(string symbol, DateTime startDate, DateTime endDate) { IList <Rate> chooseList = new List <Rate>(); chooseList = dbService.FindRate(symbol, startDate, endDate); if (chooseList == null) { string table = dbService.FindTableCode(symbol); var apiResponse = await request.GetRequestAsync( url.GetNbpRatesRequest(table.ToLower(), symbol.ToLower(), startDate, endDate), format : "?format=json"); string path; IList <Rate> rateList = new List <Rate>(); path = apiResponse.responseData; rateList = DbMapper.MapObject(path); foreach (Rate element in rateList) { Console.WriteLine(element.Price); dbService.AddRate(element); } return(rateList); } return(chooseList); }