Some questions about socket

Question

I’m taking a look at an example of microsoft itself and I’m having some doubts.

Example taken from this link: https://msdn.microsoft.com/pt-br/library/bew39x2a(v=vs.110). aspx

Let’s imagine a chat environment via socket... Should I establish a socket connection whenever sending a message? Follows the method of example:

private static void StartClient()
    {
        // Connect to a remote device.
        try
        {
            // Establish the remote endpoint for the socket.
            // The name of the 
            // remote device is "host.contoso.com".
            IPHostEntry ipHostInfo = Dns.GetHostEntry("127.0.0.1");
            IPAddress ipAddress = ipHostInfo.AddressList[0];
            IPEndPoint remoteEP = new IPEndPoint(ipAddress, port);

            // Create a TCP/IP socket.
            Socket client = new Socket(AddressFamily.InterNetwork,
                SocketType.Stream, ProtocolType.Tcp);

            // Connect to the remote endpoint.
            client.BeginConnect(remoteEP,
                new AsyncCallback(ConnectCallback), client);
            connectDone.WaitOne();

            // Send test data to the remote device.
            Send(client, "This is a test<EOF>");
            sendDone.WaitOne();

            // Receive the response from the remote device.
            Receive(client);
            receiveDone.WaitOne();

            // Write the response to the console.
            Console.WriteLine("Response received : {0}", response);

            // Release the socket.
            client.Shutdown(SocketShutdown.Both);
            client.Close();

        }
        catch (Exception e)
        {
            Console.WriteLine(e.ToString());
        }
    }

In this example is created the connection, and sent a message, then awaits the return of the message and finally closes the connection.

Can I keep one connection open and send multiple messages separately? In the case of sendDone.WaitOne(), what in fact this method does?

When I run the communication on a separate thread, it works perfectly but when executing the command on the main thread the project gets stuck, as if it was waiting for a return (which by the way never arrives rsrs)

In the case below I have a method that sends the information to the socket connection:

client.BeginSend(byteData, 0, byteData.Length, 0,
            new AsyncCallback(SendCallback), client);

where client is the type Socket;

byteData represents the information I am sending, which is the best way to convert an object with values to byte and server side byte converter for the same object type?

my initial intention is to make a communicator, like a chat server, where there would be rooms and groups. In this case every client should also be a server to always listen to the server messages?

In the client I can create a thread that will be exclusive to "listen" and perform the tasks according to the return?

If you have any educational material that addresses these and more details let me know :))

Answer 1

Let’s go in pieces:

I can keep one connection open and send multiple messages separately?

Can! In the case of a chat application, including, you will have to leave this socket open, since the server (or client, in the case of a P2P chat) has to find an open connection with your station, and this connection will be made available by opening the socket

In the case of sendDone.Waitone(), what in fact this method does?

I saw the code in MSDN, and sendDone, receiveDone and connectDone are each an instance of a Manualresetevent. It is a way to notify multiple threads that a particular operation has been executed. In this case, when I send/receive messages or even connect to the server successfully, I call the Set method. When using Waitone in a thread, you wait for another thread to call the Set method to release the continuation.

what is the best way to convert an object with values to byte and in server side convert byte to same object type?

There are some ways to do that. If you are sending a simple string, for example, you can call Encoding.default.Getbytes(string); if you are sending a complex type, you can use the Binaryformatter class

In this case every client should also be a server to stay always listening to the server messages?

Considering that you need to make groups, I recommend that you make a central server and manage the exchange of messages there; However, somehow your socket will be responsible for receiving and sending data to/from the server

In the client I can create a thread that will be exclusive to "listen" and perform the tasks according to the return?

Can.