private async Task <LatestFetch> Fetch()
{
var previous = _Latest;
var fetch = new LatestFetch();
try
{
var rates = await _Inner.GetRatesAsync();
fetch.Latest = rates;
fetch.Expiration = DateTimeOffset.UtcNow + ValidatyTime;
fetch.NextRefresh = DateTimeOffset.UtcNow + RefreshRate;
}
catch (Exception ex)
{
if (previous != null)
{
fetch.Latest = previous.Latest;
fetch.Expiration = previous.Expiration;
}
else
{
fetch.Expiration = DateTimeOffset.UtcNow;
}
fetch.NextRefresh = DateTimeOffset.UtcNow;
fetch.Exception = ex;
}
_Latest = fetch;
fetch.GetResult(); // Will throw if not valid
return(fetch);
}
public void LoadState(BackgroundFetcherState state)
{
if (state.LastRequested is DateTimeOffset lastRequested)
{
this.LastRequested = state.LastRequested;
}
if (state.LastUpdated is DateTimeOffset updated && state.Rates is List <BackgroundFetcherRate> rates)
{
var fetch = new LatestFetch()
{
Latest = rates.Select(r => new PairRate(r.Pair, r.BidAsk)).ToArray(),
Updated = updated,
NextRefresh = updated + RefreshRate,
Expiration = updated + ValidatyTime
};
_Latest = fetch;
}
}
public void LoadState(BackgroundFetcherState state)
{
if (ExchangeName != state.ExchangeName)
{
throw new InvalidOperationException("The state does not belong to this fetcher");
}
if (state.LastRequested is DateTimeOffset lastRequested)
{
this.LastRequested = state.LastRequested;
}
if (state.LastUpdated is DateTimeOffset updated && state.Rates is List <BackgroundFetcherRate> rates)
{
var fetch = new LatestFetch()
{
Latest = rates.Select(r => new PairRate(r.Pair, r.BidAsk)).ToArray(),
Updated = updated,
NextRefresh = updated + RefreshRate,
Expiration = updated + ValidatyTime
};
_Latest = fetch;
}
}
private async Task <LatestFetch> Fetch(CancellationToken cancellationToken)
{
cancellationToken.ThrowIfCancellationRequested();
var previous = _Latest;
var fetch = new LatestFetch();
fetch.ExchangeName = ExchangeName;
try
{
var rates = await _Inner.GetRatesAsync(cancellationToken);
fetch.Latest = rates;
fetch.Updated = DateTimeOffset.UtcNow;
fetch.Expiration = fetch.Updated + ValidatyTime;
fetch.NextRefresh = fetch.Updated + RefreshRate;
}
catch (Exception ex)
{
if (previous != null)
{
fetch.Latest = previous.Latest;
fetch.Expiration = previous.Expiration;
fetch.Backoff = previous.Backoff * 2;
if (fetch.Backoff > MaxBackoff)
{
fetch.Backoff = MaxBackoff;
}
}
else
{
fetch.Expiration = DateTimeOffset.UtcNow;
}
fetch.NextRefresh = DateTimeOffset.UtcNow + fetch.Backoff;
fetch.Exception = ex;
}
_Latest = fetch;
fetch.GetResult(); // Will throw if not valid
return(fetch);
}
private async Task <LatestFetch> Fetch()
{
var fetch = new LatestFetch();
try
{
var rates = await _Inner.GetRatesAsync();
fetch.Latest = rates;
}
catch (Exception ex)
{
fetch.Exception = ex;
}
fetch.Timestamp = DateTimeOffset.UtcNow;
_Latest = fetch;
if (fetch.Exception != null)
{
ExceptionDispatchInfo.Capture(fetch.Exception).Throw();
}
return(fetch);
}
public void InvalidateCache()
{
_Latest = null;
}
