Using a NetworkStream to transfer a file

Question

I am having trouble transferring a file to a client from a server program. A few problems I would like to address. First is that I make the byte array 6000 bytes big and its always that size. Is there a way to maintain the correct file size? Also with the way the code is now, the program hangs. It works when I take it out of the while loop on the client side. Help!!

Client:

 private void button1_Click(object sender, EventArgs e)
    {   
        BinaryWriter binWriter; 
        int i = -1;
        Byte[] bytes = new Byte[6000];

        NetworkStream clientStream = connTemp.GetStream();
        byte[] outstream = Encoding.ASCII.GetBytes(txtMessage.Text);
        clientStream.Write(outstream, 0, outstream.Length);


        while (i != 0)
        {
            try
            {
                if (clientStream.CanRead)
                {
                    i = clientStream.Read(bytes, 0, bytes.Length);

                }
            }

            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
                break;
            }
        }


        binWriter = new BinaryWriter(File.Open("C:\\SeanLaunch\\log.rxlog",FileMode.Create));
        binWriter.Write(bytes);
        binWriter.Close();

    }

}

Server:

  Byte[] fileToSendAsByteArray = new Byte[6000];
  fileToSendAsByteArray = File.ReadAllBytes("C:\\Launch\\Test.rxlog");
  stream.Write(fileToSendAsByteArray, 0, fileToSendAsByteArray.Length);

EDIT!!!: I fixed the looping issue.

Answer 1

The program will loop forever if CanRead remains false while i is non-zero. Or, it may be blocked on the Read call.

Debug your receive side to find out what's going on. Is it really hung, or just looping?

Add code to dump the data sent and received on each end to see how far you read OK before the problems arise.

Answer 2

One problem is that you are writing the entire 6000 bytes to the stream even if you only read one byte from the file.

Use a FileStream to access the file and copy the content to the NetworkStream. Framework 4.0 has a nice function for this

FileStream fs = new FileStream(...);
fs.CopyTo(stream);

You can take a similar approach for the client side, just in reverse, copy from the NetworkStream to the target Stream.

Prior to Framework 4.0 you can implement you own CopyTo function. Something like this

public static long CopyStream(Stream source, Stream target)
{
  const int bufSize = 0x1000;
  byte[] buf = new byte[bufSize];

  long totalBytes = 0;
  int bytesRead = 0;

  while ((bytesRead = source.Read(buf, 0, bufSize)) > 0)
  {
    target.Write(buf, 0, bytesRead);
    totalBytes += bytesRead;
  }
  return totalBytes;
}