/// <summary>
/// Retrieves data to be used in an algorithm.
/// If file does not exist, an attempt is made to download them from the api
/// </summary>
/// <param name="key">File path representing where the data requested</param>
/// <returns>A <see cref="Stream"/> of the data requested</returns>
public override Stream Fetch(string key)
{
return(DownloadOnce(key, s =>
{
// Verify we have enough credit to handle this
var pricePath = _api.FormatPathForDataRequest(key);
var price = _dataPrices.GetPrice(pricePath);
// No price found
if (price == -1)
{
throw new ArgumentException($"ApiDataProvider.Fetch(): No price found for {pricePath}");
}
if (_purchaseLimit < price)
{
throw new ArgumentException($"ApiDataProvider.Fetch(): Cost {price} for {pricePath} data exceeds remaining purchase limit: {_purchaseLimit}");
}
if (DownloadData(key))
{
// Update our purchase limit.
_purchaseLimit -= price;
}
}));
}
public void FormattingPathForDataRequestsAreCorrect(string dataFolder, string dataToDownload)
{
var api = new Api.Api();
api.Initialize(TestAccount, TestToken, dataFolder);
var path = Path.Combine(dataFolder, dataToDownload);
var result = api.FormatPathForDataRequest(path);
Assert.AreEqual(dataToDownload.Replace("\\", "/", StringComparison.InvariantCulture), result);
}
public void FormattingPathForDataRequestsAreCorrect(string dataFolder)
{
var api = new Api.Api();
api.Initialize(TestAccount, TestToken, dataFolder);
var dataToDownload = "forex/oanda/daily/eurusd.zip";
var path = Path.Combine(dataFolder, dataToDownload);
var result = api.FormatPathForDataRequest(path);
Assert.AreEqual(dataToDownload, result);
}
