private async Task StartImpl()
{
_cancellationTokenSource = new CancellationTokenSource();
var cancellationToken = _cancellationTokenSource.Token;
Exception exRoot = null;
//download all remaiing parts
var ranges = DownloadedRanges.Where(x => !x.IsDone);
await ForEachAsync(ranges, async range =>
{
Exception ex2 = null;
for (var i = 0; i < MaxRetyCount + 1 && !_cancellationTokenSource.IsCancellationRequested; i++) // retry
{
try
{
await DownloadPart(range, cancellationToken).ConfigureAwait(true);
exRoot = null;
return; // finished
}
catch (Exception ex)
{
ex2 = ex;
}
}
// just first exception treated as the exception; next exceptions such as CancelOperationException should be ignored
lock (_monitor)
{
if (exRoot == null)
{
exRoot = ex2;
}
// cancel other jobs
_cancellationTokenSource.Cancel(); // cancel all other parts
}
}, MaxPartCount, _cancellationTokenSource.Token).ConfigureAwait(false);
// release _cancellationTokenSource
_cancellationTokenSource.Dispose();
_cancellationTokenSource = null;
if (exRoot != null)
{
throw exRoot;
}
}
private async Task Init3()
{
try
{
//make sure stream is created
GetStream();
// download the header
using var httpClient = new HttpClient();
using var requestMessage = new HttpRequestMessage(HttpMethod.Head, Uri);
var response = await httpClient.SendAsync(requestMessage, _cancellationTokenSource.Token).ConfigureAwait(false);
if (response.StatusCode != HttpStatusCode.OK)
{
throw new Exception($"StatusCode is {response.StatusCode}");
}
IsResumingSupported = AllowResuming && response.Headers.AcceptRanges.Contains("bytes");
TotalSize = response.Content.Headers.ContentLength ?? 0;
if (response.Content.Headers.ContentLength == null)
{
throw new Exception($"Could not retrieve the stream size: {Uri}");
}
// create new download range if previous size is different
if (DownloadedRanges.Length == 0 || DownloadedRanges.Sum(x => x.To - x.From + 1) != TotalSize)
{
DownloadedRanges = BuildDownloadRanges(TotalSize, IsResumingSupported && MaxPartCount >= 2 ? PartSize : TotalSize);
}
// finish initializing
State = DownloadState.Initialized;
}
catch (Exception ex)
{
SetLastError(ex);
throw;
}
finally
{
_cancellationTokenSource.Dispose();
_cancellationTokenSource = null;
_initTask.SetResult(null);
lock (_monitorState)
{
_initTask = null;
}
}
}
public Downloader(DownloaderOptions options)
{
if (options is null)
{
throw new ArgumentNullException(nameof(options));
}
if (options.PartSize < 10000)
{
throw new ArgumentException("PartSize parameter must be equals or greater than 10000", nameof(options.PartSize));
}
Uri = options.Uri;
_stream = options.Stream;
_writeBufferSize = options.WriteBufferSize;
DownloadedRanges = options.DownloadedRanges ?? Array.Empty <DownloadRange>();
MaxPartCount = options.MaxPartCount;
MaxRetyCount = options.MaxRetryCount;
PartSize = options.PartSize;
State = options.IsStopped ? DownloadState.Stopped : DownloadState.None;
AutoDisposeStream = options.AutoDisposeStream;
AllowResuming = options.AllowResuming;
TotalSize = options.DownloadedRanges != null && options.DownloadedRanges.Length > 0 ? DownloadedRanges.Sum(x => x.To - x.From + 1) : 0;
}