How can I receive data from socket continuously?

Question

I'm trying to receive data from a socket via Windows Service, but when I make a connection it becomes instant. I want to receive it constantly (It will disconnect when port is closed). How can I achieve this?

This is my output for now;

"GET / HTTP/1.1

Host: 127.0.0.1:1994

Connection: keep-alive

Cache-Control: max-age=0

Upgrade-Insecure-Requests: 1

User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/51.0.2704.106 Safari/537.36

Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,/;q=0.8

Accept-Encoding: gzip, deflate, sdch

Accept-Language: tr-TR,tr;q=0.8,en-US;q=0.6,en;q=0.4

Connection proceed? False"

using System;
using System.IO;
using System.Net;
using System.Text;
using System.Linq;
using System.Threading;
using System.Net.Sockets;
using System.Diagnostics;
using System.ComponentModel;
using System.ServiceProcess;
using System.Collections.Generic;

namespace AServiceTest
{
    public partial class Service1 : System.ServiceProcess.ServiceBase
    {
        Thread th;
        bool isRunning = false;
        byte[] bytes = new byte[1024];

        public Service1() 
        {
            InitializeComponent();
        }
        protected override void OnStart(string[] args)
        {
            th = new Thread(DoThis);
            th.Start();
            isRunning = true;            
        }
        private void DoThis()
        {
            while (isRunning)
            {
                    Socket listener, connecter, acc;
                    listener = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
                    connecter = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp); //Variables

                    listener.Bind(new IPEndPoint(IPAddress.Parse("127.0.0.1"), 1994));
                    listener.Listen(0);

                    acc = listener.Accept(); //Accepting comm with client part
                    bool IsConnected = !((listener.Poll(1000, SelectMode.SelectRead) && (listener.Available == 0)) || !listener.Connected);

                    File.AppendAllText(@"D:\Tasks\dataGathering.txt", Environment.NewLine + "Connection proceed?1 " + IsConnected);


                new Thread(() =>
                {

                    byte[] bytes = new byte[1024];
                    int byteCount = acc.Receive(bytes, SocketFlags.None);

                    File.AppendAllText(@"D:\Tasks\dataGathering.txt", Environment.NewLine + "Connection proceed?2 " + IsConnected);

                    Console.WriteLine(Encoding.UTF8.GetString(bytes)); //It encodes before writing to the screen
                    File.AppendAllText(@"D:\Tasks\dataGathering.txt", Environment.NewLine + " " + Encoding.UTF8.GetString(bytes));

                    File.AppendAllText(@"D:\Tasks\dataGathering.txt", Environment.NewLine + "Connection proceed?3 " + IsConnected);


                    File.AppendAllText(@"D:\Tasks\dataGathering.txt", Environment.NewLine + "Connection proceed? " + IsConnected);
                    Console.WriteLine("Does connection proceeding? " + IsConnected);

                }).Start();
            }
        }        
        protected override void OnStop() 
        {
            isRunning = false;
            th = null;
        }
        private void InitializeComponent() 
        {
            this.ServiceName = "AServiceTest";
            this.CanStop = true;
            this.AutoLog = false;
            this.EventLog.Log = "Application";
            this.EventLog.Source = "Service1";
        }
    }
}

hazevich hazevich · Accepted Answer · 2016-06-29T07:38:38

To receive data continuously you actually need to put in some loop.

for example:

private void StartProcessing(Socket serverSocket)
{
    var clientSocket = serverSocket.Accept();
    StartReceiveing(clientSocket);
}

private void StartReceiveing(Socket clientSocket)
{
    const int maxBufferSize = 1024;

    try
    {
        while (true)
        {
            var buffer = new byte[maxBufferSize];

            var bytesRead = clientSocket.Receive(buffer);

            if (ClientIsConnected(clientSocket))
            {
                var actualData = new byte[bytesRead];

                Array.Copy(buffer, actualData, bytesRead);
                OnDataReceived(actualData);
            }
            else
            {
                OnDisconnected(clientSocket);
            }
        }
    }
    catch (SocketException ex)
    {
        Console.WriteLine(ex.Message);
    }
}

private void OnDisconnected(Socket issuedSocket)
{
    if (issuedSocket != null)
    {
        issuedSocket.Shutdown(SocketShutdown.Both);
        issuedSocket.Close();

        StartProcessing(listener);
    }
}

private void OnDataReceived(byte[] data)
{
    //do cool things
}

private static bool ClientIsConnected(Socket socket)
{
    return !(socket.Poll(1000, SelectMode.SelectRead) && socket.Available == 0);
}

Also, in your case, I consider reading about socket async API and about Tasks and async programming. With those you could do some cool and clean things, like:

await Task.Factory.FromAsync(serverSocket.BeginAccept, result => serverSocket.EndAccept(result), serverSocket);

Which wan't block your current Thread.

How can I receive data from socket continuously?

1 Answers