I'm very new to all that TCP thing and I just can't find what's going wrong here. It might be pretty obvious for some of you. When I run the code, I run the Start process on the Server side, it displays 'waiting for connection', then I start the client, the later displays 'connected to ', I relaunch the start process on the server side and it displays 'Connected to the client' and then, on both sides, when I call the method SendThroughTCPSocket("whatever string"), I can see it being sent but nothing is being detected on the other side ?
What could I be doing wrong ?
How could I have both of them constantly listening to each other ?
SERVER SIDE :
using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
namespace Server
{
// State object for reading client data asynchronously
public class StateObject
{
#region instance variables
// Client socket.
public Socket workSocket = null;
// Size of receive buffer.
public const int BufferSize = 1024;
// Receive buffer.
public byte[] buffer = new byte[BufferSize];
// Received data string.
public StringBuilder sb = new StringBuilder();
#endregion
}
public class AsynchronousSocketListener
{
public enum TransmissionSate
{
Waiting,
Receiving,
Received,
Sending,
Sent,
Off
}
#region class variables
// Thread signal.
public static ManualResetEvent allDone = new ManualResetEvent(false);
public static IPHostEntry ipHostInfo;
public static IPAddress ipAddress;
public static IPEndPoint localEndPoint;
public static Socket listener;
public static Socket handler;
//flags
public static TransmissionSate currentState = TransmissionSate.Off;
#endregion
#region constructor
public AsynchronousSocketListener()
{
}
#endregion
#region Start Listening
//Start Listening for Client
public static void StartListening()
{
// Data buffer for incoming data.
byte[] bytes = new Byte[1024];
// Establish the local endpoint for the socket.
// The DNS name of the computer
ipHostInfo = Dns.Resolve(Dns.GetHostName());
ipAddress = ipHostInfo.AddressList[0];
localEndPoint = new IPEndPoint(ipAddress, 11000);
// Create a TCP/IP socket.
listener = new Socket(AddressFamily.InterNetwork,
SocketType.Stream, ProtocolType.Tcp);
// Bind the socket to the local endpoint and listen for incoming connections.
try
{
listener.Bind(localEndPoint);
listener.Listen(100);
while (true)
{
// Set the event to nonsignaled state.
allDone.Reset();
// Start an asynchronous socket to listen for connections.
Console.WriteLine("Waiting for a connection...");
listener.BeginAccept(
new AsyncCallback(AcceptCallback),
listener);
//flag
currentState = TransmissionSate.Waiting;
// Wait until a connection is made before continuing.
allDone.WaitOne();
}
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
Console.WriteLine("\nConnected to the client.");
//Console.Read();
}
#endregion
#region Receive Methods
//Accept communication and Start reading
public static void AcceptCallback(IAsyncResult ar)
{
// Signal the main thread to continue.
allDone.Set();
// Get the socket that handles the client request.
listener = (Socket)ar.AsyncState;
handler = listener.EndAccept(ar);
//flag
currentState = TransmissionSate.Receiving;
// Create the state object.
StateObject state = new StateObject();
state.workSocket = handler;
handler.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
new AsyncCallback(ReadCallback), state);
}
//Read and handle the information
public static void ReadCallback(IAsyncResult ar)
{
String content = String.Empty;
// Retrieve the state object and the handler socket
// from the asynchronous state object.
StateObject state = (StateObject)ar.AsyncState;
handler = state.workSocket;
// Read data from the client socket.
int bytesRead = handler.EndReceive(ar);
if (bytesRead > 0)
{
// There might be more data, so store the data received so far.
state.sb.Append(Encoding.ASCII.GetString(
state.buffer, 0, bytesRead));
// Check for end-of-file tag. If it is not there, read
// more data.
content = state.sb.ToString();
if (content.IndexOf("<EOF>") > -1)
{
//flag
currentState = TransmissionSate.Received;
// All the data has been read from the
// client. Display it on the console.
Console.WriteLine("Read {0} bytes from socket. \n Data : {1}",
content.Length, content);
//reference
Data.lastResponse = content;
//react
Console.WriteLine("Server just received a request");
switch (content)
{
case "DataRequest":
Console.WriteLine("Client is trying to get the preset data");
SendThroughTCPSocket(Data.xmlToSend + Data.endOfFile);
break;
default:
Console.WriteLine("Unknown request from Client");
break;
}
}
else
{
// Not all data received. Get more.
handler.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
new AsyncCallback(ReadCallback), state);
}
}
}
#endregion
#region Send Methods
//Send data to a socket
private static void Send(Socket handler, String data)
{
// Convert the string data to byte data using ASCII encoding.
byte[] byteData = Encoding.ASCII.GetBytes(data);
//flag
currentState = TransmissionSate.Sending;
// Begin sending the data to the remote device.
handler.BeginSend(byteData, 0, byteData.Length, 0,
new AsyncCallback(SendCallback), handler);
}
//Sending data and closing handler
private static void SendCallback(IAsyncResult ar)
{
try
{
// Retrieve the socket from the state object.
Socket handler = (Socket)ar.AsyncState;
// Complete sending the data to the remote device.
int bytesSent = handler.EndSend(ar);
Console.WriteLine("Sent {0} bytes to client.", bytesSent);
//flag
currentState = TransmissionSate.Sent;
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
}
#endregion
#region SendThroughTCPSocket
public static void SendThroughTCPSocket(String data)
{
try
{
// Send data to the client
Send(handler, data);
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
}
#endregion
#region Stop Server
//Close Sever
public static void StopServer()
{
try
{
// Release the socket.
handler.Shutdown(SocketShutdown.Both);
handler.Close();
//flag
currentState = TransmissionSate.Off;
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
}
#endregion
}
}
CLIENT SIDE :
using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
namespace Client
{
// State object for receiving data from remote device.
public class StateObject
{
#region instance variables
// Client socket.
public Socket workSocket = null;
// Size of receive buffer.
public const int BufferSize = 256;
// Receive buffer.
public byte[] buffer = new byte[BufferSize];
// Received data string.
public StringBuilder sb = new StringBuilder();
#endregion
}
public class AsynchronousClient
{
public enum TransmissionSate
{
Waiting,
Receiving,
Received,
Sending,
Sent,
Off
}
#region instance variables
// The port number for the remote device.
private const int port = 11000;
#endregion
#region class variables
// ManualResetEvent instances signal completion.
private static ManualResetEvent connectDone =
new ManualResetEvent(false);
private static ManualResetEvent sendDone =
new ManualResetEvent(false);
private static ManualResetEvent receiveDone =
new ManualResetEvent(false);
// The response from the remote device.
private static String response = String.Empty;
public static IPHostEntry ipHostInfo;
public static IPAddress ipAddress;
public static IPEndPoint remoteEP;
public static Socket client;
//flags
public static TransmissionSate currentState = TransmissionSate.Off;
public static bool isConnected = false;
#endregion
#region Start Client
//Start Client and use it
public static void StartClient()
{
// Connect to a remote device.
try
{
//flag
isConnected = false;
// Establish the remote endpoint for the socket.
// The name of the host
// remote device is the current device
ipHostInfo = Dns.Resolve(Dns.GetHostName());
ipAddress = ipHostInfo.AddressList[0];
remoteEP = new IPEndPoint(ipAddress, port);
// Create a TCP/IP socket.
client = new Socket(AddressFamily.InterNetwork,
SocketType.Stream, ProtocolType.Tcp);
// Connect to the remote endpoint.
client.BeginConnect(remoteEP,
new AsyncCallback(ConnectCallback), client);
connectDone.WaitOne();
//flag
currentState = TransmissionSate.Waiting;
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
}
#endregion
#region Stop Client
//Close Client
public static void StopClient()
{
try
{
// Release the socket.
client.Shutdown(SocketShutdown.Both);
client.Close();
//flag
currentState = TransmissionSate.Off;
isConnected = false;
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
}
#endregion
#region Connect
//callback for connection
private static void ConnectCallback(IAsyncResult ar)
{
try
{
// Retrieve the socket from the state object.
Socket client = (Socket)ar.AsyncState;
// Complete the connection.
client.EndConnect(ar);
Console.WriteLine("Socket connected to {0}",
client.RemoteEndPoint.ToString());
// Signal that the connection has been made.
connectDone.Set();
//flag
isConnected = true;
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
}
#endregion
#region Receive
//Receive data
private static void Receive(Socket client)
{
try
{
// Create the state object.
StateObject state = new StateObject();
state.workSocket = client;
//flag
currentState = TransmissionSate.Receiving;
// Begin receiving the data from the remote device.
client.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
new AsyncCallback(ReceiveCallback), state);
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
}
//callback Receive
private static void ReceiveCallback(IAsyncResult ar)
{
try
{
// Retrieve the state object and the client socket
// from the asynchronous state object.
StateObject state = (StateObject)ar.AsyncState;
Socket client = state.workSocket;
// Read data from the remote device.
int bytesRead = client.EndReceive(ar);
if (bytesRead > 0)
{
// There might be more data, so store the data received so far.
state.sb.Append(Encoding.ASCII.GetString(state.buffer, 0, bytesRead));
// Get the rest of the data.
client.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
new AsyncCallback(ReceiveCallback), state);
}
else
{
// All the data has arrived; put it in response.
if (state.sb.Length > 1)
{
response = state.sb.ToString();
}
// Signal that all bytes have been received.
receiveDone.Set();
//flag
currentState = TransmissionSate.Received;
}
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
}
#endregion
#region Send
//Send data
private static void Send(Socket client, String data)
{
// Convert the string data to byte data using ASCII encoding.
byte[] byteData = Encoding.ASCII.GetBytes(data);
//flag
currentState = TransmissionSate.Sending;
// Begin sending the data to the remote device.
client.BeginSend(byteData, 0, byteData.Length, 0,
new AsyncCallback(SendCallback), client);
}
//Callback send
private static void SendCallback(IAsyncResult ar)
{
try
{
// Retrieve the socket from the state object.
Socket client = (Socket)ar.AsyncState;
// Complete sending the data to the remote device.
int bytesSent = client.EndSend(ar);
Console.WriteLine("Sent {0} bytes to server.", bytesSent);
// Signal that all bytes have been sent.
sendDone.Set();
//flag
currentState = TransmissionSate.Sent;
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
}
#endregion
#region SendThroughTCPSocket
public static string SendThroughTCPSocket(String data)
{
try
{
// Send data to the remote device.
Send(client, data);
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);
return response;
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
return "<No response>";
}
}
#endregion
}
}
