private static async Task <StocksJSON> ProcessResponseAsync(HttpWebResponse response)
{
string json = "";
using (var streamReader = new StreamReader(response.GetResponseStream()))
{
json = await streamReader.ReadToEndAsync();
}
var jsSerializer = new JavaScriptSerializer();
StocksJSON stocks = null;
try
{
stocks = jsSerializer.Deserialize <StocksJSON>(json);
}
catch (Exception e)
{
_logger.Error("Error during serializing JSON data:" + e.Message);
stocks = null;
throw;
}
return(stocks);
}
public async Task <StocksJSON> GetCurrentStocksAsync()
{
var request = (HttpWebRequest)WebRequest.Create(_url);
request.Method = WebRequestMethods.Http.Get;
request.Accept = "application/json";
HttpWebResponse response = await GetResponseAsync(request);
StocksJSON stocks = null;
if (response != null && response.StatusCode == HttpStatusCode.OK)
{
stocks = await ProcessResponseAsync(response);
}
return(stocks);
}
/// <summary>
/// Save stocks if not exists and creates stock values (if newer) for them.
/// </summary>
/// <param name="stocks"></param>
/// <returns></returns>
public bool AddStockWithValues(StocksJSON stocks)
{
int addedOrUpdatedStocks = 0;
foreach (var stock in stocks.Items)
{
try
{
int stockId = AddStockIfNotExists(stock.Code, stock.Name);
if (AddStockValueIfNewer(stockId, stock.Unit, stock.Price, stocks.PublicationDate))
{
addedOrUpdatedStocks++;
}
}
catch (Exception e)
{
_logger.Error("Exception: " + e.Message);
}
}
return(addedOrUpdatedStocks > 0);
}
/// <summary>
/// Save stock values for existing stocks if provided stock's publication date is newer.
/// </summary>
/// <param name="stocks"></param>
/// <returns></returns>
public bool AddStockValuesForExistingStocksIfNewer(StocksJSON stocks)
{
if (stocks == null)
{
throw new ArgumentNullException();
}
if (stocks.Items?.Count == 0)
{
return(false);
}
// select max publication date for stock values
var maxPublicationDate = _db.StockValue
.Select(x => x.PublicationDate).Max();
// prepare stock codes
var codesList = stocks.Items.Select(x => x.Code).ToList();
// select existing stocks
var existingStocks = _db.Stock
.AsNoTracking()
.Where(x => codesList.Contains(x.Code.ToLower()))
.ToList();
// check whether max publication date is older than publication date of fetched data
if (DateTime.Compare(maxPublicationDate, stocks.PublicationDate) > -1) // first date is newer than or equal to second date
{
_logger.Info("Data skipped for publication date: " + stocks.PublicationDate.ToString());
return(false);
}
// ...there was an update
var stockValues = new List <StockValue>();
existingStocks.ForEach(stock =>
{
var price = stocks.Items
.Where(x => x.Code.ToLower().Equals(stock.Code.ToLower()))
.Select(x => x.Price)
.FirstOrDefault();
var unit = stocks.Items
.Where(x => x.Code.ToLower().Equals(stock.Code.ToLower()))
.Select(x => x.Unit)
.FirstOrDefault();
//var stockInfo = $"{stock.ID}, price={price}, unit={unit}";
//_logger.Info(stockInfo);
stockValues.Add(new StockValue
{
StockID = stock.ID,
Price = price,
Unit = unit,
PublicationDate = stocks.PublicationDate
});
});
using (var dbContextTransaction = _db.Database.BeginTransaction())
{
try
{
stockValues.ForEach(s => _db.StockValue.Add(s));
int affectedRows = _db.SaveChanges();
dbContextTransaction.Commit();
_logger.Info("Successfully added new stocks values.");
return(affectedRows > 0);
}
catch (Exception e)
{
_logger.Error("Error during adding stocks values: " + e.Message);
_logger.Info("Rollback");
dbContextTransaction.Rollback();
return(false);
}
}
}
