public static bool Download(string destinationPath, Uri sourceURL, BackgroundWorker bw)
{
int bufferSize = 1024 * 1024;
long existLen = 0;
var response = new ComplexResponse();
System.IO.FileStream saveFileStream = null;
try
{
System.IO.Stream resStream;
System.Net.HttpWebRequest httpReq;
System.Net.HttpWebResponse httpRes;
httpReq = (System.Net.HttpWebRequest)System.Net.HttpWebRequest.Create(sourceURL);
httpReq.Proxy = null;
response.FileSize = GetFileSize(sourceURL);
if (System.IO.File.Exists(destinationPath) ) //check only when it accepts ranges at all
{
System.IO.FileInfo destinationFileInfo = new System.IO.FileInfo(destinationPath);
existLen = destinationFileInfo.Length;
response.Message = string.Format("File exists and has {0} bytes.", existLen);
bw.Report(response);
}
if (existLen >= response.FileSize)
return true;
httpReq.AddRange(existLen);
httpRes = (System.Net.HttpWebResponse)httpReq.GetResponse();
var acceptRanges = String.Compare(httpRes.Headers["Accept-Ranges"], "bytes", true) == 0; //check if server accepts ranges
if (existLen > 0 && acceptRanges) //if retry is available
saveFileStream = new System.IO.FileStream(destinationPath, FileMode.Append, FileAccess.Write, FileShare.ReadWrite);
else
saveFileStream = new System.IO.FileStream(destinationPath, FileMode.Create, FileAccess.Write, FileShare.ReadWrite);
resStream = httpRes.GetResponseStream();
response.TotalBytes = httpRes.ContentLength;
response.Message = string.Format("Remote file has {0} bytes left.", response.TotalBytes);
bw.Report(response);
if (response.TotalBytes < 0)
throw new WebException("File has no data or does not exist");
int byteSize;
byte[] downBuffer = new byte[bufferSize];
while ((byteSize = resStream.Read(downBuffer, 0, downBuffer.Length)) > 0)
{
if (bw.CancellationPending == true)
{
response.Message = "Cancelling";
bw.Report(response);
httpRes.Close();
break;
}
response.CurrentBytes += byteSize;
saveFileStream.Write(downBuffer, 0, byteSize);
{
response.Message = string.Empty;
response.Percent = (response.CurrentBytes * 100.0 / response.TotalBytes);
if (response.Percent > 100)
response.Percent = 100;
bw.Report(response);
}
}
saveFileStream.Close();
response.Message = string.Format("Downloaded {0} bytes.", response.CurrentBytes);
bw.Report(response);
return response.CurrentBytes == response.TotalBytes;
}
catch (Exception ex)
{
response.Message = string.Format("{0} - {1}", ex.GetType(), ex.Message);
response.IsError = true;
bw.Report(response);
return false;
}
finally
{
if (saveFileStream != null)
saveFileStream.Dispose();
}
}
public static void Report(this BackgroundWorker worker, ComplexResponse resp)
{
if (worker == null)
return;
worker.ReportProgress((int)resp.Percent, resp);
}