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Hi

I hope someone can help me with this problem.

When I close the connection by calling Quit(), sometimes I get an IOException when the control socket tries to flush its output stream. My theory is that it seems the server has already closed the connection. This code is in a try, finally block, so it still cleans up, but this exception is not handled anywhere and propagates up to my code.

I can do this:
try{ myftpClient.Quit() }
catch(IOException) {}


But I'm wondering if there's a better way.

Here's the exception text:

System.IO.IOException: Unable to write data to the transport connection. ---> System.Net.Sockets.SocketException: An existing connection was forcibly closed by the remote host
at System.Net.Sockets.Socket.Send(Byte[] buffer, Int32 offset, Int32 size, SocketFlags socketFlags)
at System.Net.Sockets.NetworkStream.Write(Byte[] buffer, Int32 offset, Int32 size)
--- End of inner exception stack trace ---
at System.Net.Sockets.NetworkStream.Write(Byte[] buffer, Int32 offset, Int32 size)
at System.IO.StreamWriter.Flush(Boolean flushStream, Boolean flushEncoder)
at System.IO.StreamWriter.Flush()
at EnterpriseDT.Net.Ftp.FTPControlSocket.SendCommand(String command)
at EnterpriseDT.Net.Ftp.FTPClient.Quit()


Also, sometimes I get this exception on Quit(), during the ReadReply:

System.IO.IOException: Unable to read data from the transport connection. ---> System.Net.Sockets.SocketException: Overlapped I/O operation is in progress
at System.Net.Sockets.Socket.Receive(Byte[] buffer, Int32 offset, Int32 size, SocketFlags socketFlags)
at System.Net.Sockets.NetworkStream.Read(Byte[] buffer, Int32 offset, Int32 size)
--- End of inner exception stack trace ---
at System.Net.Sockets.NetworkStream.Read(Byte[] buffer, Int32 offset, Int32 size)
at System.IO.StreamReader.ReadBuffer()
at System.IO.StreamReader.ReadLine()
at EnterpriseDT.Net.Ftp.FTPControlSocket.ReadReply()
at EnterpriseDT.Net.Ftp.FTPControlSocket.SendCommand(String command)
at EnterpriseDT.Net.Ftp.FTPClient.Quit()

Thanks,

Le

1 Answer

0 votes
by (161k points)
Is it possible that the connection has timed out? Has the FTP client been idle for a time before calling quit? In this case the server may well have closed the connection. This could be the cause of both errors ...

Is there anything useful in the log file?

Hi

I hope someone can help me with this problem.

When I close the connection by calling Quit(), sometimes I get an IOException when the control socket tries to flush its output stream. My theory is that it seems the server has already closed the connection. This code is in a try, finally block, so it still cleans up, but this exception is not handled anywhere and propagates up to my code.

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