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I am using ftp for downloading a zip file(size 10 MB to 70 MB) from server it was perfectly downloading but, when the network is slow, the error the operation has timed out in ftp is showing and then it comes to catch(Exception ex) in that the download() is called once again so it is redownloading again and again.

This project is created in .NET framework 4.0

I have increased the time of ftpWebRequest.Timeout = 6000; but still it doesn't work

public void Download(string localDirectory,string localFilename,string remoteDirectory,string remoteFileName) 
{

    string client_path=Path.GetDirectoryName(Path.GetDirectoryName(Path.GetDirectoryName(localDirectory)));

    string appPath = System.IO.Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().Location);
    string configFile = System.IO.Path.Combine(appPath, "PACS.exe.config");

    ExeConfigurationFileMap configFileMap = new ExeConfigurationFileMap();
    configFileMap.ExeConfigFilename = configFile;

    System.Configuration.Configuration config = ConfigurationManager.OpenMappedExeConfiguration(configFileMap, ConfigurationUserLevel.None);

    config.AppSettings.Settings["client_path"].Value = client_path;
    config.Save(ConfigurationSaveMode.Modified);
    ConfigurationManager.RefreshSection("appSettings");

    string str = Path.Combine(localDirectory, localFilename);
    FileInfo fileInfo = new FileInfo(str);
    FileStream fileStream = (FileStream)null;

    WebException webException;

    try
    {

        string path = Path.GetDirectoryName(Path.GetDirectoryName(remoteDirectory));

        string path1 = Path.GetDirectoryName(Path.GetDirectoryName(localDirectory));

        WebRequest sizeRequest = WebRequest.Create("ftp://" + "IP" + ":" + "port" + "/" + "C:\\KINSOLUTIONS\\Team\\Images\\1" + ".zip");

        sizeRequest.Credentials = (ICredentials)new NetworkCredential("UserName", "Password");

        sizeRequest.Method = WebRequestMethods.Ftp.GetFileSize;

        int size = (int)sizeRequest.GetResponse().ContentLength;

        FtpWebRequest ftpWebRequest = WebRequest.Create(new Uri("ftp://" + "IP" + ":" + "port" + "/" + "C:\\KINSOLUTIONS\\Team\\Images\\1" + ".zip")) as FtpWebRequest;

        ftpWebRequest.Credentials = (ICredentials)new NetworkCredential("UserName", "Password");

        ftpWebRequest.UsePassive = true;

        ftpWebRequest.Timeout = 6000;
        ftpWebRequest.KeepAlive = false;
        ftpWebRequest.Method = "RETR";
        ftpWebRequest.UseBinary = true;
        fileStream = new FileStream(path1 + ".zip", FileMode.Create, FileAccess.Write, FileShare.ReadWrite);

        using(Stream responseStream = (ftpWebRequest.GetResponse() as FtpWebResponse).GetResponseStream())                
        {                   

            byte[] buffer = new byte[32768];

            int count = responseStream.Read(buffer, 0, 32768);                    

            long num = (long)count;                    

            int post = 0;

            while (size != post || count != 0 )
            {
                bool result = System.Net.NetworkInformation.NetworkInterface.GetIsNetworkAvailable();
                while (!result)
                {
                    result = System.Net.NetworkInformation.NetworkInterface.GetIsNetworkAvailable();
                    if (result)
                    {
                        fileStream.Close();
                        Download(localDirectory, localFilename, remoteDirectory, remoteFileName);
                    }
                }

                fileStream.Write(buffer, 0, count);
                count = responseStream.Read(buffer, 0, 32768);
                int position = (int)fileStream.Position;
                num += (long)count;                  
                post = position;
            }
            fileStream.Close();
        }
    }

    catch (WebException ex)
    {
        if (fileStream != null)
            fileStream.Close();                
            this.Download(localDirectory, localFilename, remoteDirectory, remoteFileName);
    }

    finally
    {
        if (fileStream != null)
            fileStream.Close();
    }
}

Is there any other option for downloading the zip file in slow network?

S.Orioli
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Hari Prasath
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    set the timeout for more than 6 seconds? set keepalive to true? – BugFinder Apr 15 '19 at 09:40
  • 1
    Keepalive will hardly help with a download of a single file. Though setting a longer timeout can help. – Martin Prikryl Apr 15 '19 at 10:10
  • Remove count from following : while (size != post || count != 0 ) FTP/http uses TCP as the transport layer. TCP can have a KeepAlive message where you receive and message with zero bytes. When the network is slow you may get a keepalive with zero bytes and then stop in the middle of the download. – jdweng Apr 15 '19 at 10:49
  • Or even better, do not re-invent the wheel and use some standard (and simpler) code: https://stackoverflow.com/q/2781654/850848#44794524 – Martin Prikryl Apr 15 '19 at 11:23

0 Answers0