Programming Tutorials

Server Socket Program sample in VB.net

By: Issac in VB.net Tutorials on 2009-02-21  

The Server Socket Program is a VB.NET Console based Application. This program acts as a Server and listens to client's request. We have to assign Port 8888 for the Server Socket, it is an instance of the VB.NET Class TcpListener, and call its start () method.

Dim serverSocket As New TcpListener (8888)
serverSocket.Start ()

Next we are creating an infinite loop for continuous communication to Client. When Server gets the request, it reads the data from NetworkStream and also writes the response to NetworkStream. For doing this create a new VB.NET Console Application Project and put the following source code into project.

Imports System.Net.Sockets
Imports System.Text
Module Module1
    Sub Main()
        Dim serverSocket As New TcpListener(8888)
        Dim requestCount As Integer
        Dim clientSocket As TcpClient
        serverSocket.Start()
        msg("Server Started")
        clientSocket = serverSocket.AcceptTcpClient()
        msg("Accept connection from client")
        requestCount = 0

        While (True)
            Try
                requestCount = requestCount + 1
                Dim networkStream As NetworkStream = _
                        clientSocket.GetStream()
                Dim bytesFrom(10024) As Byte
networkStream.Read(bytesFrom, 0, CInt(clientSocket.ReceiveBufferSize))
                Dim dataFromClient As String = _
                        System.Text.Encoding.ASCII.GetString(bytesFrom)
                dataFromClient = _
            dataFromClient.Substring(0, dataFromClient.IndexOf("$"))
                msg("Data from client -  " + dataFromClient)
                Dim serverResponse As String = _
                    "Server response " + Convert.ToString(requestCount)
                Dim sendBytes As [Byte]() = _
                    Encoding.ASCII.GetBytes(serverResponse)
                networkStream.Write(sendBytes, 0, sendBytes.Length)
                networkStream.Flush()
                msg(serverResponse)
            Catch ex As Exception
                MsgBox(ex.ToString)
            End Try
        End While


        clientSocket.Close()
        serverSocket.Stop()
        msg("exit")
        Console.ReadLine()
    End Sub

    Sub msg(ByVal mesg As String)
        mesg.Trim()
        Console.WriteLine(" >> " + mesg)
    End Sub
End Module

This server socket is in only a part of the socket program,we need a client to test it fully, we will see about it in detail in the client socket programming tutorial, you should first start the Server Socket Program and then start the Client Socket Program.