public async Task Download(IDownloadable downloadable)
{
GetPermission(Manifest.Permission.ReadExternalStorage);
GetPermission(Manifest.Permission.WriteExternalStorage);
var activity = Mvx.Resolve <IMvxAndroidCurrentTopActivity>().Activity;
activity.GetExternalMediaDirs();
var targetDirectory = Settings.DestinationDirectory;
var fileName = $"{targetDirectory}/{downloadable.Name}";
var fileSize = 0L;
if (File.Exists(fileName))
{
var fileInfo = new FileInfo(fileName);
fileSize = fileInfo.Length;
}
var client = new HttpClient(new NativeMessageHandler());
var request = new HttpRequestMessage(HttpMethod.Get, downloadable.Url);
if (fileSize > 0)
{
request.Headers.Range = new RangeHeaderValue(fileSize, null);
}
var response = await client.SendAsync(
request,
HttpCompletionOption.ResponseHeadersRead);
if (response.IsSuccessStatusCode == false)
{
downloadable.UpdateProgress(0, 0, $"error: {response.ReasonPhrase}");
return;
}
var receivedBytes = (int)fileSize;
using (var netStream = await response.Content.ReadAsStreamAsync())
{
using (var fileStream = new FileOutputStream(fileName, true))
{
var buffer = new byte[ChunkSize];
var totalBytes = (response.Content.Headers.ContentLength ?? -1) + fileSize;
var speed = 0;
var lastUpdate = DateTime.Now;
var stopWatch = new Stopwatch();
stopWatch.Start();
var lastReceivedBytes = 0;
_sentData = new CircularBuffer(MeasureCount);
for (;;)
{
var bytesRead = await netStream.ReadAsync(buffer, 0, buffer.Length);
if (bytesRead == 0)
{
await Task.Yield();
break;
}
receivedBytes += bytesRead;
await fileStream.WriteAsync(buffer, 0, bytesRead);
if (DateTime.Now > lastUpdate + TimeSpan.FromMilliseconds(MeasureSpan))
{
_sentData.Add(receivedBytes - lastReceivedBytes);
speed = _sentData.GetAverage() / (int)stopWatch.Elapsed.TotalMilliseconds;
stopWatch.Restart();
downloadable.UpdateProgress((double)receivedBytes / totalBytes, speed);
lastUpdate = DateTime.Now;
lastReceivedBytes = receivedBytes;
}
}
downloadable.UpdateProgress((double)receivedBytes / totalBytes, speed);
}
}
}
