Errors coming while uploading images to FTP

Question

I am getting a lot of different issues in this function :

public static bool UploadToFTP(string strFileName, string strFolderName)
        {
            bool isUploaded = false;
            string strFilename = string.Empty;
            string strFtpURI = string.Empty;
            string strFtpUserId = string.Empty;
            string strFtpPassword = string.Empty;
            byte[] buffer = null;
            FileInfo oFileInfo = null;
            FileStream oFileStream = null;
            FtpWebRequest oFtpWebRequest = null;

            try
            {
                strFilename = strFileName;
                oFileInfo = new FileInfo(strFilename);
                strFtpURI = Constants.FtpUri;
                strFtpUserId = Constants.FtpUserID;
                strFtpPassword = Constants.FtpPassword;

                oFtpWebRequest = (FtpWebRequest)FtpWebRequest.Create(new Uri(strFtpURI + "/" + strFolderName + "/" + oFileInfo.Name));

                oFtpWebRequest.Credentials = new NetworkCredential(strFtpUserId, strFtpPassword);
                oFtpWebRequest.Proxy = null;
                oFtpWebRequest.KeepAlive = false;
                oFtpWebRequest.Method = WebRequestMethods.Ftp.UploadFile;
                oFtpWebRequest.UseBinary = true;
                oFtpWebRequest.ContentLength = oFileInfo.Length;

                int iBufferLength = 2084;

                buffer = new byte[iBufferLength];

                int iContentLength = 0;

                oFileStream = oFileInfo.OpenRead();

                try
                {
                    iContentLength = oFileStream.Read(buffer, 0, iBufferLength);

                    using (Stream oStream = oFtpWebRequest.GetRequestStream())
                    {
                        while (iContentLength != 0)
                        {
                            oStream.Write(buffer, 0, iContentLength);

                            iContentLength = oFileStream.Read(buffer, 0, iBufferLength);
                        }
                        isUploaded = true;
                        FtpUpload.TotalKBFilesUploaded =  FtpUpload.TotalKBFilesUploaded + (int)(oFileInfo.Length / 1000);
                    }
                }
                catch (Exception ex)
                {

                }
                finally
                {
                    if (oFtpWebRequest != null)
                    {
                        oFtpWebRequest.Abort();
                        oFtpWebRequest = null;
                    }

                    if (buffer != null)
                    {
                        buffer = null;
                    }

                    if (oFileStream != null)
                    {
                        oFileStream.Close();
                        oFileStream.Dispose();
                    }
                }
            }
            catch (Exception ex)
            {
            }
            finally
            {
                oFileInfo = null;
            }

            return isUploaded;
        }

This is uploading 1000s of images to FTP, and this methos is called in multi threaded way.

Different errors are :

=======================================================

Message:The operation has timed out

Error Trace: at System.Net.FtpWebRequest.CheckError() at System.Net.FtpWebRequest.GetRequestStream()

=======================================================

Error Message:Unable to connect to the remote server

Error Trace: at System.Net.FtpWebRequest.CheckError() at System.Net.FtpWebRequest.GetRequestStream()

=======================================================

Error Message:The underlying connection was closed: An unexpected error occurred on a receive.

Error Trace: at System.Net.FtpWebRequest.CheckError() at System.Net.FtpWebRequest.SyncRequestCallback(Object obj) at System.Net.CommandStream.Abort(Exception e) at System.Net.FtpWebRequest.FinishRequestStage(RequestStage stage) at System.Net.FtpWebRequest.GetRequestStream()

=======================================================

Error Message:Unable to write data to the transport connection: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.

Error Trace: at System.Net.Sockets.NetworkStream.Write(Byte[] buffer, Int32 offset, Int32 size) at System.Net.FtpDataStream.Write(Byte[] buffer, Int32 offset, Int32 size) =======================================================

These are few errors coming from the same method which I retrieved from LOG file.

Any idea what could be causing this? OR I need to give some more detail?

Answer 1

The following exception is encountered when a timeout is reached :

Error Message:The underlying connection was closed: An unexpected error occurred on a receive.

As explained in the msdn documentation the default value of the timeout is infinite but the msdn documentation contains a mistake: http://msdn.microsoft.com/fr-fr/library/vstudio/system.net.ftpwebrequest.timeout(v=vs.80).aspx

In fact, the default value is 100000 ms (1 min and 40 sec) so you can declare the value Timeout to infinite with : oFtpWebRequest.Timeout = -1;

http://www.sidesofmarch.com/index.php/archive/2012/04/06/damn-the-documentation-ftpwebrequest-timeout-default-value-is-not-infinite/