Client/server socket application problem - files sent are incomplete

Hello all

I am having problems with a Client / Server application I am writing. I want to send a file from a client app to a server app, and I have created code to do so. I am using VB.NET 2003 and testing on WinXP SP2 for both machines (firewalls disabled).

However I have run up against an apparently insurmountable problem (for me). When I test by running both apps on the same computer I have no problems, receiving the test file properly but when I run the client from another PC on my LAN the file only comes through partially (truncated). I have also noted that if I step through the receiving code of the server manually, it works properly even across the LAN, so I can't see where the problem is happening.

At present I have disabled the multithreading code to test just a single file and isolate the problem.

My Client data send subroutine looks like this:

Private Sub SendData()

        Dim filebuffer As Byte()
        Dim fileStream As Stream

        ' open a file and retrieve its bytes
        fileStream = File.OpenRead(tbFilename.Text)
        ReDim filebuffer(fileStream.Length)
        fileStream.Read(filebuffer, 0, fileStream.Length)

        ' Open a TCP Connection and send the data
        Dim clientSocket As New System.Net.Sockets.TcpClient(tbServer.Text, 8222)
        clientSocket.SendBufferSize = 4096
        clientSocket.SendTimeout = 5000 '5 seconds
        Dim networkStream As NetworkStream
        networkStream = clientSocket.GetStream()
        networkStream.Write(filebuffer, 0, fileStream.Length)
        networkStream.Flush()
        networkStream.Close()
        clientSocket.Close()

    End Sub



The relevant Server code looks like this:



Public Sub handlerThread()
        Try
            Dim handlerSocket As Socket                     'define the socket locally
            handlerSocket = alSockets(alSockets.Count - 1)  'get the last socket added to the alSockets array
            handlerSocket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.SendTimeout, 5000)
            Dim networkStream As NetworkStream = New NetworkStream(handlerSocket) 'create a network stream
            Dim blockSize As Integer = 4096                '
            Dim thisRead As Integer
            Dim dataByte(blockSize) As Byte
            SyncLock Me
                Dim fileStream As Stream
                fileStream = File.OpenWrite("c:\zzzzzz " + RandObj.Next.ToString + ".jpg") 'Make a new file to save to
                Do
                    thisRead = networkStream.Read(dataByte, 0, blockSize)
                    fileStream.Write(dataByte, 0, thisRead)
                Loop While networkStream.DataAvailable
                fileStream.Close()
            End SyncLock
            lbConnections.Items.Add("File Written")
            handlerSocket = Nothing
        Catch ex As Exception
            MsgBox("Error was : " + ex.Message)
        End Try
    End Sub



I am pulling my hair out as to what might be the problem here. I have tried various socket options, block sizes, disabled the firewalls on both machines, many things really; I dont know where to go next. I have a project file with both components if that is of any help.

If there is anybody able to offer suggestions about what I am doing wrong in my code it would be greatly appreciated.