public static DownloadData Create(string url, string destFolder, IWebProxy proxy)
{
// This is what we will return
DownloadData downloadData = new DownloadData();
downloadData.proxy = proxy;
long urlSize = downloadData.GetFileSize(url);
downloadData.size = urlSize;
WebRequest req = downloadData.GetRequest(url);
try
{
downloadData.response = (WebResponse)req.GetResponse();
}
catch (Exception e)
{
throw new ArgumentException(String.Format(
"Error downloading \"{0}\": {1}", url, e.Message), e);
}
// Check to make sure the response isn't an error. If it is this method
// will throw exceptions.
ValidateResponse(downloadData.response, url);
// Take the name of the file given to use from the web server.
String fileName = System.IO.Path.GetFileName(downloadData.response.ResponseUri.ToString());
String downloadTo = Path.Combine(destFolder, fileName);
// If we don't know how big the file is supposed to be,
// we can't resume, so delete what we already have if something is on disk already.
if (!downloadData.IsProgressKnown && File.Exists(downloadTo))
{
File.Delete(downloadTo);
}
if (downloadData.IsProgressKnown && File.Exists(downloadTo))
{
// We only support resuming on http requests
if (!(downloadData.Response is HttpWebResponse))
{
File.Delete(downloadTo);
}
else
{
// Try and start where the file on disk left off
downloadData.start = new FileInfo(downloadTo).Length;
// If we have a file that's bigger than what is online, then something
// strange happened. Delete it and start again.
if (downloadData.start > urlSize)
{
File.Delete(downloadTo);
}
else if (downloadData.start < urlSize)
{
// Try and resume by creating a new request with a new start position
downloadData.response.Close();
req = downloadData.GetRequest(url);
((HttpWebRequest)req).AddRange((int)downloadData.start);
downloadData.response = req.GetResponse();
if (((HttpWebResponse)downloadData.Response).StatusCode != HttpStatusCode.PartialContent)
{
// They didn't support our resume request.
File.Delete(downloadTo);
downloadData.start = 0;
}
}
}
}
return(downloadData);
}
/// <summary>
/// Begin downloading the file at the specified url, and save it to the given folder.
/// </summary>
public void Download(string url, string destFolder)
{
DownloadData data = null;
this.canceled = false;
try
{
// get download details
data = DownloadData.Create(url, destFolder, this.proxy);
// Find out the name of the file that the web server gave us.
string destFileName = Path.GetFileName(data.Response.ResponseUri.ToString());
// The place we're downloading to (not from) must not be a URI,
// because Path and File don't handle them...
destFolder = destFolder.Replace("file:///", "").Replace("file://", "");
this.downloadingTo = Path.Combine(destFolder, destFileName);
// Create the file on disk here, so even if we don't receive any data of the file
// it's still on disk. This allows us to download 0-byte files.
if (!File.Exists(downloadingTo))
{
FileStream fs = File.Create(downloadingTo);
fs.Close();
}
// create the download buffer
byte[] buffer = new byte[downloadBlockSize];
int readCount;
// update how many bytes have already been read
long totalDownloaded = data.StartPoint;
bool gotCanceled = false;
OnDownloadStarting();
while ((int)(readCount = data.DownloadStream.Read(buffer, 0, downloadBlockSize)) > 0)
{
// break on cancel
if (canceled)
{
gotCanceled = true;
data.Close();
break;
}
// update total bytes read
totalDownloaded += readCount;
// save block to end of file
SaveToFile(buffer, readCount, this.downloadingTo);
// send progress info
if (data.IsProgressKnown)
{
RaiseProgressChanged(totalDownloaded, data.FileSize);
}
// break on cancel
if (canceled)
{
gotCanceled = true;
data.Close();
OnDownloadCancelled();
break;
}
}
if (!gotCanceled)
{
OnDownloadComplete();
}
}
catch (UriFormatException e)
{
throw new ArgumentException(
String.Format("Could not parse the URL \"{0}\" - it's either malformed or is an unknown protocol.", url), e);
}
finally
{
if (data != null)
{
data.Close();
}
}
}