public bool ValidateHttpLinks(DownloadRequest files)
{
if (files.Links == null)
{
return(false);
}
return(!files.Links.Any(x => !x.Link.ToLower().StartsWith("http://")));
}
public List <string> GetDuplicatedFiles(DownloadRequest files)
{
if (files.Links == null)
{
return(new List <string>());
}
List <string> duplicatedFiles = files.Links.GroupBy(x => x.Filename).Where(w => w.Count() > 1).Select(s => s.Key).ToList();
return(duplicatedFiles);
}
public List <FileDownloadDefinition> GetGroupedLinks(DownloadRequest files)
{
if (files.Links == null)
{
return(new List <FileDownloadDefinition>());
}
var items = files.Links.GroupBy(x => x.Link).Select(x => new FileDownloadDefinition(x)).ToList();
return(items);
}
public async Task Download(DownloadRequest files)
{
if (files.Links == null || files.Links.Count == 0)
{
return;
}
if (!ValidateHttpLinks(files))
{
return;
}
var tasks = new List <Task>();
if (files.Threads < 1)
{
files.Threads = 1;
}
var duplicated = GetDuplicatedFiles(files);
if (duplicated.Count != 0)
{
return;
}
//Semaphore to control max concurrent parallel downloads.
var semaphore = new SemaphoreSlim(files.Threads, files.Threads);
//Fix Duplicated links to different file names
var currentDownloadDefinitions = GetGroupedLinks(files);
_definitions.AddRange(currentDownloadDefinitions);
var downloadTasks = new List <Task>();
foreach (var link in currentDownloadDefinitions)
{
var downloadTask = Task.Run(async() =>
{
var freshLink = link;
var fileStreams = new List <FileStream>();
await semaphore.WaitAsync();
_logger.LogInformation("{link}, Started", freshLink.FileDefinitions[0].Link);
freshLink.Status = State.Downloading;
freshLink.Started = DateTime.Now;
freshLink.BytesDownloaded = 0;
try
{
HttpWebRequest req = (HttpWebRequest)WebRequest.Create(freshLink.FileDefinitions[0].Link);
var response = await req.GetResponseAsync();
using (var reponseStream = response.GetResponseStream())
{
foreach (var fileDefinition in freshLink.FileDefinitions)
{
if (!Directory.Exists(_downloadFolder))
{
Directory.CreateDirectory(_downloadFolder);
}
fileStreams.Add(new FileStream(Path.Combine(_downloadFolder, fileDefinition.Filename), FileMode.OpenOrCreate));
}
const int bufferSize = 1024 * 500; //500kb
var buffer = new byte[bufferSize];
int bytesRead = 0;
var stopwatch = new Stopwatch();
do
{
stopwatch.Restart();
//reponseStream.Seek(downloader.Start, SeekOrigin.Current);
bytesRead = await reponseStream.ReadAsync(buffer, 0, bufferSize);
stopwatch.Stop();
freshLink.BytesDownloaded += bytesRead;
foreach (var fs in fileStreams)
{
await fs.WriteAsync(buffer, 0, bytesRead);
}
decimal speed = bytesRead / (decimal)1024;
speed = speed / (decimal)stopwatch.Elapsed.TotalSeconds;
freshLink.CurrentSpeed = $"{Math.Round(speed, 2)} kb/s";
} while (bytesRead > 0);
freshLink.DownloadEnd = DateTime.Now;
freshLink.Status = State.Finished;
}
}
catch (Exception e)
{
freshLink.Status = State.Error;
_logger.LogError(e, $"Error downloading [{freshLink.FileDefinitions[0].Link}].");
}
finally
{
foreach (var fs in fileStreams)
{
fs.Close();
}
semaphore.Release();
}
});
downloadTasks.Add(downloadTask);
}
await Task.WhenAll(downloadTasks);
_logger.LogInformation("all requested downloads finished");
}