CODEWITHSUNDEEP
c#.netsocketsbinary
Kyle
Kyle

Reputation: 29

Sending Binary 0 over socket connection in c#/.Net

I am working on an application where I need to send a command over a socket connection and then receive the data it sends back. I am having difficulty getting anything back from the server after sending my command. I was told initially to "end the package with a binary 0", and I think this is what might be throwing me off as I am not really sure how to do this in c#. Here is some source code:

    Socket sender = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);

            try
            {
                sender.Connect(remoteEp);
                Console.WriteLine("Socket connected to {0}", sender.RemoteEndPoint.ToString());
                byte zero = Encoding.Default.GetBytes("0")[0];

                byte[] msg = Encoding.ASCII.GetBytes("PACK_ALARM.ALARM_GETCOUNTI,294,0" + zero);

                int bytesSent = sender.Send(msg);

                int bytesReceived = sender.Receive(bytes);
                Console.WriteLine("Test = {0}", Encoding.ASCII.GetString(bytes, 0, bytesReceived));

                sender.Shutdown(SocketShutdown.Both);
                sender.Close();
            }
            catch (ArgumentNullException ane)
            {
                Console.Write("ArgumentNullException : {0}", ane.ToString());
            }
            catch (SocketException se)
            {
                Console.WriteLine("Socket Exception : {0}", se.ToString());
            }
            catch (Exception e)
            {
                Console.WriteLine("Unexpected exception : {0}", e.ToString());
            }
        }
        catch (Exception ex)
        {
            Console.WriteLine(ex.ToString());
        }

Upvotes: 0

Views: 529

Answers (1)

Luaan
Luaan

Reputation: 63772

You're not sending a binary zero. You're sending the ASCII representation of the character '0', converted to a number, converted to a string.

Instead, just do this:

byte[] msg = Encoding.ASCII.GetBytes("PACK_ALARM.ALARM_GETCOUNTI,294,0\0");

The \0 is a literal for the null character - binary zero.

Also, note that TCP is a stream protocol, not a message-based protocol. You're supposed to keep Receiveing in a loop until you get the whole message. For short, infrequent messages, your code might work (unreliably), but any real communication is going to result in a horrible mess.

Upvotes: 1

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