CODEWITHSUNDEEP
c#socketsclient-server
Zeeshan Arif
Zeeshan Arif

Reputation: 499

C# Socket Programming: server does not accept client connections

I am new to socket programming in C#. Have searched the web like crazy for the solution to my problem but didnt find anything that could fix it. So heres my problem:

I am trying to write a client-server application. For the time being, the server will also run on my local machine. The application transmits a byte stream of data from the client to the server. The problem is that the server doesnt detect a client request for connection, while the client is able to connect and transmit the byte stream.

here is the server code:

String strHostName = Dns.GetHostName();
Console.WriteLine(strHostName);
IPAddress ip = IPAddress.Parse("127.0.0.1");
ipEnd = new IPEndPoint(ip, port);
soc = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.IP);
soc.Bind(ipEnd);

Console.WriteLine("Web Server Running... Press ^C to Stop...");

Thread th = new Thread(new ThreadStart(StartListen));
th.Start();

The StartListen thread is as below:

public void StartListen()
{
    try
    {
        while (true)
        {
            string message;
            Byte[] bSend = new Byte[1024];
            soc.Listen(100);

            if (soc.Connected)
            {
                Console.WriteLine("\nClient Connected!!\n==================\n CLient IP {0}\n", soc.RemoteEndPoint);
                Byte[] bReceive = new Byte[1024 * 5000];
                int i = soc.Receive(bReceive);

The client code is as follows:

hostIPAddress = IPAddress.Parse("127.0.0.1");
ipEnd = new IPEndPoint(hostIPAddress,port);
Socket clientSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.IP);

Console.WriteLine("Connecting to Server...");
clientSocket.Connect(ipEnd);
Console.WriteLine("Sending File...");
clientSocket.Send(clientData);
Console.WriteLine("Disconnecting...");
clientSocket.Close();
Console.WriteLine("File Transferred...");

Now what happens is that the server starts and when I run the client, it connects, sends and closes. But nothing happens on the server console, it doesnt detect any connection: if (soc.Connected) remains false.

I checked whether the server was listening to 127.0.0.1:5050 through netstat, and it sure was listening. Cant figure out the problem. Please help.

Upvotes: 0

Views: 3968

Answers (1)

Sergey Vyacheslavovich Brunov
Sergey Vyacheslavovich Brunov

Reputation: 18106

On the server side use Socket.Accept Method to accept incoming connection. The method returns a Socket for a newly created connection: the Send() and Receive() methods can be used for this socket.

For example, after accepting the separate thread can be created to process the client connection (i.e. client session).

private void ClientSession(Socket clientSocket)
{
    // Handle client session:
    // Send/Receive the data.
}

public void Listen()
{
    Socket serverSocket = ...;

    while (true)
    {
        Console.WriteLine("Waiting for a connection...");
        var clientSocket = serverSocket.Accept();

        Console.WriteLine("Client has been accepted!");
        var thread = new Thread(() => ClientSession(clientSocket))
            {
                IsBackground = true
            };
        thread.Start();
    }
}

Upvotes: 2

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