private void OnGetFileInfo(DownloadFileInfo downloadFileInfo)
{
try
{
FileInfoReceived?.Invoke(this, new FileInfoReceivedEventArgs {
DownloadFileInfo = downloadFileInfo
});
}
catch (Exception ex)
{
OnExceptionThrown(ex);
}
}
private List <Range> PrepareRanges(DownloadFileInfo info, int numberOfParallelDownloads)
{
var readRanges = new List <Range>();
long lastRangeStart = 0;
try
{
if (info.IsSupportedRange)
{
for (int chunk = 0; chunk < numberOfParallelDownloads - 1; chunk++)
{
var range = new Range
{
Start = chunk * (info.Length / numberOfParallelDownloads),
End = ((chunk + 1) * (info.Length / numberOfParallelDownloads)) - 1
};
readRanges.Add(range);
lastRangeStart = range.End + 1;
}
}
//last range which we add always even if the Range header is not supported
readRanges.Add(new Range
{
Start = lastRangeStart,
End = info.Length - 1
});
for (int i = 0; i < readRanges.Count; i++)
{
readRanges[i].Index = i;
readRanges[i].Buffer = new byte[readRanges[i].End - readRanges[i].Start + 1];
}
}
catch (Exception ex)
{
OnExceptionThrown(ex);
}
return(readRanges);
}
private DownloadResult DownloadRanges(DownloadFileInfo info, List <Range> readRanges, CancellationToken cancel)
{
// Parallel download
var result = new DownloadResult {
FileUrl = info.FileUrl, FileExists = info.Exists, FileLength = info.Length, ParallelDownloads = readRanges.Count
};
long bytesDownloaded = 0;
try
{
if (cancel.IsCancellationRequested)
{
result.IsCancelled = true;
return(result);
}
int numberOfThreads = readRanges.Count;
var mutex = new ManualResetEvent(false);
var progressChangedEventArgs = new ProgressChangedEventArgs
{
FileUrl = info.FileUrl, FileLength = info.Length
};
StartProgressThread(progressChangedEventArgs);
StartBandwidthThread(progressChangedEventArgs);
var sw = Stopwatch.StartNew();
foreach (var readRange in readRanges)
{
new Thread(_ =>
{
try
{
log.Debug($"{readRange.Index} started. Range: {readRange.Start}-{readRange.End}");
int rangeLen = readRange.Buffer.Length;
int offset = 0;
const int blockSize = 4096;
int triesCount = 0;
bool success = false;
while (!success && !mutex.WaitOne(0) && triesCount < MaxTriesCount)
{
try
{
var httpWebRequest = (HttpWebRequest)WebRequest.Create(info.FileUrl);
httpWebRequest.Method = "GET";
if (info.IsSupportedRange)
{
httpWebRequest.AddRange((int)readRange.Start + offset, (int)readRange.End);
}
httpWebRequest.Timeout = TimeoutMs;
httpWebRequest.ReadWriteTimeout = TimeoutMs;
using (var httpWebResponse = (HttpWebResponse)httpWebRequest.GetResponse())
{
using (var responseStream = httpWebResponse.GetResponseStream())
{
int bytesRead;
while ((bytesRead = responseStream.Read(readRange.Buffer,
offset,
rangeLen - offset < blockSize ? rangeLen - offset : blockSize
)) > 0 && !cancel.IsCancellationRequested)
{
offset += bytesRead;
Interlocked.Add(ref bytesDownloaded, bytesRead);
lock (progressChangedEventArgs)
{
progressChangedEventArgs.Progress = bytesDownloaded;
progressChangedEventArgs.ElapsedMs = sw.ElapsedMilliseconds;
Monitor.PulseAll(progressChangedEventArgs);
}
}
}
success = true;
}
}
catch (Exception ex)
{
//reset offset if server does not support range
if (!info.IsSupportedRange)
{
offset = 0;
}
log.Warn(
$"Exception {ex.Message}. index={readRange.Index} offset={offset} uri={info.FileUrl}");
WaitNetwork(ref triesCount);
}
}
//If one thread is failed signalize other threads to exit.
//If all threads completed signalize the method to return download result
if (!success || Interlocked.Decrement(ref numberOfThreads) == 0)
{
mutex.Set();
}
log.Debug($"{readRange.Index} completed. Success = {success}. Range: {readRange.Start}-{readRange.End}");
}
catch (Exception ex)
{
OnExceptionThrown(ex);
}
})
{
IsBackground = true
}.Start();
}
mutex.WaitOne();
sw.Stop();
result.BytesDownloaded = bytesDownloaded;
result.IsOperationSuccess = Interlocked.CompareExchange(ref numberOfThreads, 0, 0) == 0;
result.IsCancelled = cancel.IsCancellationRequested;
}
catch (Exception ex)
{
OnExceptionThrown(ex);
}
return(result);
}
public DownloadFileInfo GetFileInfo(string fileUrl)
{
var info = new DownloadFileInfo {
FileUrl = fileUrl
};
int triesCount = 0;
try
{
while (!info.IsOperationSuccess && triesCount < MaxTriesCount)
{
try
{
//we must create web request each time to prevent DNS caching
var webRequest = (HttpWebRequest)WebRequest.Create(fileUrl);
webRequest.Method = "HEAD";
webRequest.Timeout = TimeoutMs;
webRequest.ReadWriteTimeout = TimeoutMs;
using (var webResponse = webRequest.GetResponse())
{
info.Length = long.Parse(webResponse.Headers.Get("Content-Length"));
info.IsSupportedHead = true;
info.Exists = true;
info.IsOperationSuccess = true;
}
}
catch (WebException ex)
{
var status = (ex.Response as HttpWebResponse)?.StatusCode;
//File does not exist on server, return
if (status == HttpStatusCode.Forbidden || status == HttpStatusCode.NotFound)
{
return(info);
}
log.Warn("WebException during getting HEAD", ex);
WaitNetwork(ref triesCount);
}
catch (Exception ex)
{
log.Warn("Exception during getting HEAD download", ex);
WaitNetwork(ref triesCount);
}
}
info.IsOperationSuccess = false;
triesCount = 0;
while (!info.IsOperationSuccess && triesCount < MaxTriesCount)
{
try
{
//we must create web request each time to prevent DNS caching
var webRequest = (HttpWebRequest)WebRequest.Create(fileUrl);
webRequest.AddRange(0, (int)info.Length - 1);
webRequest.Method = "HEAD";
webRequest.Timeout = TimeoutMs;
webRequest.ReadWriteTimeout = TimeoutMs;
using (var webResponse = (HttpWebResponse)webRequest.GetResponse())
{
info.IsSupportedRange = webResponse.StatusCode == HttpStatusCode.PartialContent ||
webResponse.GetResponseHeader("Accept-Ranges") == "bytes";
info.IsOperationSuccess = true;
}
}
catch (WebException ex)
{
var status = (ex.Response as HttpWebResponse)?.StatusCode;
//File does not exist on server, return
if (status == HttpStatusCode.Forbidden || status == HttpStatusCode.NotFound)
{
return(info);
}
log.Warn("WebException during getting HEAD", ex);
WaitNetwork(ref triesCount);
}
catch (Exception ex)
{
log.Warn("Exception during getting HEAD download", ex);
WaitNetwork(ref triesCount);
}
}
}
catch (Exception ex)
{
OnExceptionThrown(ex);
}
return(info);
}
