private void OnOpenReadCompleted(object sender, OpenReadCompletedEventArgs args)
{
DownloadWebClient webClient = sender as DownloadWebClient;
if (webClient == null)
{
return;
}
lock (this.cancelSync)
{
if (this.isCancelled)
{
return;
}
if (!webClient.HasResponse)
{
this.TriggerWebClientDownloadFileAsync();
return;
}
bool appendExistingChunk = webClient.IsPartialResponse;
Stream destinationStream = this.CreateDestinationStream(appendExistingChunk);
if (destinationStream != null)
{
this.TrySetStreamReadTimeout(args.Result, (int)this.SourceStreamReadTimeout.TotalMilliseconds);
this.worker = new StreamCopyWorker();
this.worker.Completed += this.OnWorkerCompleted;
this.worker.ProgressChanged += this.OnWorkerProgressChanged;
this.worker.CopyAsync(args.Result, destinationStream, this.TotalBytesToReceive);
}
}
}
private void TryCleanupExistingDownloadWebClient()
{
if (this.downloadWebClient == null)
{
return;
}
try
{
lock (this)
{
if (this.downloadWebClient != null)
{
this.downloadWebClient.DownloadFileCompleted -= this.OnDownloadCompleted;
this.downloadWebClient.DownloadProgressChanged -= this.OnDownloadProgressChanged;
this.downloadWebClient.OpenReadCompleted -= this.OnOpenReadCompleted;
this.downloadWebClient.CancelAsync();
this.downloadWebClient.Dispose();
this.downloadWebClient = null;
}
}
}
catch (Exception)
{
}
}
private DownloadWebClient CreateWebClient()
{
DownloadWebClient webClient = new DownloadWebClient();
webClient.DownloadFileCompleted += this.OnDownloadCompleted;
webClient.DownloadProgressChanged += this.OnDownloadProgressChanged;
webClient.OpenReadCompleted += this.OnOpenReadCompleted;
return(webClient);
}
private void Download(Uri source, string fileDestination, long totalBytesToReceive)
{
try
{
FileUtils.TryGetFileSize(fileDestination, out long seekPosition);
this.TryCleanupExistingDownloadWebClient();
this.downloadWebClient = this.CreateWebClient();
this.downloadWebClient.OpenReadAsync(source, seekPosition);
}
catch (Exception e)
{
if (!this.AttemptDownload())
{
this.InvokeDownloadCompleted(CompletedState.Failed, this.localFileName, e);
}
}
}
private void TriggerWebClientDownloadFileAsync()
{
try
{
this.isFallback = true;
string destinationDirectory = Path.GetDirectoryName(this.localFileName);
if (destinationDirectory != null && !Directory.Exists(destinationDirectory))
{
Directory.CreateDirectory(destinationDirectory);
}
this.TryCleanupExistingDownloadWebClient();
this.downloadWebClient = this.CreateWebClient();
this.downloadWebClient.DownloadFileAsync(this.fileSource, this.localFileName);
}
catch (Exception ex)
{
if (!this.AttemptDownload())
{
this.InvokeDownloadCompleted(CompletedState.Failed, this.localFileName, ex);
}
}
}
private void TriggerWebClientDownloadFileAsync()
{
try
{
isFallback = true;
var destinationDirectory = Path.GetDirectoryName(localFileName);
if (destinationDirectory != null && !Directory.Exists(destinationDirectory))
{
Directory.CreateDirectory(destinationDirectory);
}
TryCleanupExistingDownloadWebClient();
downloadWebClient = CreateWebClient();
downloadWebClient.DownloadFileAsync(fileSource, localFileName);
}
catch (Exception ex)
{
if (!AttemptDownload())
{
InvokeDownloadCompleted(CompletedState.Failed, localFileName, ex);
}
}
}
/// <summary>
/// OnDownloadCompleted event handler
/// </summary>
/// <param name="sender">Sender object</param>
/// <param name="args">AsyncCompletedEventArgs instance</param>
protected void OnDownloadCompleted(object sender, AsyncCompletedEventArgs args)
{
DownloadWebClient webClient = sender as DownloadWebClient;
if (webClient == null)
{
//logger.Warn("Wrong sender in OnDownloadCompleted: Actual:{0} Expected:{1}", sender.GetType(), typeof(DownloadWebClient));
this.InvokeDownloadCompleted(CompletedState.Failed, this.localFileName);
return;
}
if (args.Cancelled)
{
//logger.Debug("Download cancelled. Source: {0} Destination: {1}", fileSource, localFileName);
this.DeleteDownloadedFile();
this.InvokeDownloadCompleted(CompletedState.Canceled, this.localFileName);
this.readyToDownload.Set();
}
else if (args.Error != null)
{
if (this.isFallback)
{
this.DeleteDownloadedFile();
}
////We may have NameResolutionFailure on internet connectivity problem.
////We don't use DnsFallbackResolver if we successfully started downloading, and then got internet problem.
////If we change [this.fileSource] here - we lose downloaded chunk in Cache (i.e. we create a new Cache item for new [this.fileSource]
if (this.attemptNumber == 1 && this.DnsFallbackResolver != null && this.IsNameResolutionFailure(args.Error))
{
Uri newFileSource = this.DnsFallbackResolver.Resolve(this.fileSource);
if (newFileSource != null)
{
this.fileSource = newFileSource;
this.AttemptDownload();
return;
}
}
if (!this.AttemptDownload())
{
this.InvokeDownloadCompleted(CompletedState.Failed, null, args.Error);
this.readyToDownload.Set();
}
}
else
{
if (this.useFileNameFromServer)
{
this.localFileName = this.ApplyNewFileName(this.localFileName, webClient.GetOriginalFileNameFromDownload());
}
if (this.UseCaching)
{
this.downloadCache.Add(this.fileSource, this.localFileName, webClient.ResponseHeaders);
}
////we may have the destination file not immediately closed after downloading
this.WaitFileClosed(this.localFileName, TimeSpan.FromSeconds(3));
this.InvokeDownloadCompleted(CompletedState.Succeeded, this.localFileName, null);
this.readyToDownload.Set();
}
}
