Socket disconnect after read the textfile. How to maintain the connection? - c#

Here is my code:
A listener to wait for connection from client:
static void Main(string[] args)
{
IPAddress ipAddr = IPAddress.Parse(args[1]);
TcpListener listener = new TcpListener(ipAddr, Int32.Parse(args[2]));
listener.Start();
Console.WriteLine("Waiting for a connection.");
TcpClient client = listener.AcceptTcpClient();
Console.WriteLine("Client accepted.");
while (true)
{
NetworkStream stream = client.GetStream();
StreamReader sr = new StreamReader(client.GetStream());
StreamWriter sw = new StreamWriter(client.GetStream());
try
{
if (stream.DataAvailable)
{
byte[] buffer = new byte[1024];
stream.Read(buffer, 0, buffer.Length);
int recv = 0;
foreach (byte b in buffer)
{
if (b != 0)
{
recv++;
}
}
string request = Encoding.UTF8.GetString(buffer, 0, recv);
Console.WriteLine("request received: " + request);
if (request != null)
{
string response = null;
response = apiQueryAndReponse(request, args[0]);
if (response != null)
{
byte[] byData = Encoding.ASCII.GetBytes(response);
stream.Write(byData, 0, byData.Length);
stream.Flush();
}
}
}
}
catch (Exception e)
{
Console.WriteLine("Something went wrong.");
Console.WriteLine(e.Message.ToString());
//sw.WriteLine(e.ToString());
}
}
}
Get and return the response:
private static string apiQueryAndReponse(string rec, String stagingfilepath)
{
String response = null;
if (rec.Contains("GetTesterInfo"))
{
response = getLatestStatusOK("GetTesterInfo", stagingfilepath);
if (response != null)
{
Console.WriteLine("Response: " + response + "," + fileline + "\n");
fileline++;
}
}
return response;
}
Read the text file and get the response:
private static String getLatestStatusOK(String key, String filedir)
{
using (var fs = new FileStream(filedir, FileMode.Open, FileAccess.Read))
{
using (var sr = new StreamReader(fs, Encoding.UTF8))
{
while ((stagingfiledata = sr.ReadLine()) != null)
{
try
{
if (stagingfiledata.Contains(key))
{
String[] data = stagingfiledata.Split(",");
response = data[2];
}
}
catch (Exception exp)
{
Console.WriteLine("err messageļ¼š" + exp.Message);
}
}
}
}
return response;
}
What I trying to do here: I will read a text file and get response to reply to client. But the socket will disconnect after access the text file.(I have tried connect with client without call the text file access function). I want to maintain connection and read text file when it necessary.

There are a number of issues with this code.
Your primary issue: you are creating a new StreamReader and StreamWriter on each loop, and they dispose the underlying stream when they are garbage-collected.
You aren't even using those readers and writers, you may as well remove them
You are missing using in a number of places.
The number of bytes received is returned from the Read function, you do not have to guesstimate by checking for \0.
static void Main(string[] args)
{
IPAddress ipAddr = IPAddress.Parse(args[1]);
TcpListener listener = new TcpListener(ipAddr, Int32.Parse(args[2]));
listener.Start();
Console.WriteLine("Waiting for a connection.");
using TcpClient client = listener.AcceptTcpClient();
Console.WriteLine("Client accepted.");
using NetworkStream stream = client.GetStream();
while (true)
{
try
{
byte[] buffer = new byte[1024];
int recv = stream.Read(buffer, 0, buffer.Length);
string request = Encoding.UTF8.GetString(buffer, 0, recv);
Console.WriteLine("request received: " + request);
if (request != null)
{
string response = null;
response = apiQueryAndReponse(request, args[0]);
if (response != null)
{
byte[] byData = Encoding.UTF8.GetBytes(response);
stream.Write(byData, 0, byData.Length);
stream.Flush();
}
}
}
catch (Exception e)
{
Console.WriteLine("Something went wrong.");
Console.WriteLine(e.Message.ToString());
//sw.WriteLine(e.ToString());
}
}
}
There are other serious flaws with your design:
TCP does not guarantee that a single write will become a single read on the other end of the wire. Chunks of data may be split or combined. It's a stream, not a messaging protocol.
So you need a framing mechanism. The easiest one to use is to first pass the size of your data, then read that amount of bytes.
You are also not able to handle multiple clients. You need to hand off each one to a Task.
Corrollary to that, you should use async functions to improve performance and responsiveness.
You should also have a cancellation token which you can use if someone presses CTRL+C.
You probably shouldn't try to handle an exception and then continue. If an exception happens, log it and close the connection.
static CancellationTokenSource _cancellation = new();
static async Task Main(string[] args)
{
Console.CancelKeyPress += (sender, e) => _cancellation.Cancel();
IPAddress ipAddr = IPAddress.Parse(args[1]);
TcpListener listener = new TcpListener(ipAddr, Int32.Parse(args[2]));
listener.Start();
try
{
Console.WriteLine("Waiting for a connection.");
TcpClient client = await listener.AcceptTcpClientAsync(_cancellation.Token);
Console.WriteLine("Client accepted.");
Task.Run(() => HandleClient(client), _cancellation.Token);
}
catch (OperationCanceledException)
{ //
}
finally
{
listener.Stop();
}
}
private async Task HandleClient(TcpClient client)
{
using var _ = client;
await using NetworkStream stream = client.GetStream();
var lengthBuf = new byte[4];
try
{
while (true)
{
await stream.ReadExactlyAsync(lengthBuf, 0, 4, _cancellation.Token);
var length = BitConverter.ToInt32(lengthBuf, 0);
if(length > SomeMaxLengthHere || length <= 0)
throw new Exception("Too long");
byte[] buffer = new byte[length];
await stream.ReadExactly(buffer, 0, length, _cancellation.Token);
string request = Encoding.UTF8.GetString(buffer, 0, length);
Console.WriteLine("request received: " + request);
if (request != null)
{
string response = apiQueryAndReponse(request, args[0]);
if (response != null)
{
byte[] byData = Encoding.UTF8.GetBytes(response);
await stream.WriteAsync(byData, 0, byData.Length, _cancellation.Token);
await stream.FlushAsync(_cancellation.Token);
}
}
}
}
catch (OperationCanceledException)
{ //
}
catch (Exception e)
{
Console.WriteLine("Something went wrong.");
Console.WriteLine(e.Message.ToString());
//sw.WriteLine(e.ToString());
}
}

Related

TCP client - server connection

I'm trying to make client get some data from server using TCP.
But it works only once. Then stream.DataAvailable is always false.
Client code:
while (!StopEvent.WaitOne(WaitTime, true))
{
try
{
if (TcpClient == null || !TcpClient.Connected)
{
if (TcpClient != null)
{
TcpClient.Close();
TcpClient = null;
}
TcpClient = new TcpClient(MasterHost, MasterMonitoringPort) {NoDelay = true};
}
var stream = TcpClient.GetStream();
stream.WriteTimeout = TimeoutMs;
stream.ReadTimeout = TimeoutMs;
stream.Write(GetMasterStateRequestBytes, 0, GetMasterStateRequestBytes.Length);
var serialisedDataBuilder = new StringBuilder();
if (stream.DataAvailable)
{
while (stream.DataAvailable)
{
var bytesRead = stream.Read(BytesBuffer, 0, BytesBuffer.Length);
serialisedDataBuilder.Append(Encoding.UTF8.GetString(BytesBuffer, 0, bytesRead));
}
var responses = MonitoringResponse.StringToResponses(serialisedDataBuilder.ToString());
foreach (var response in responses)
{
if (response.MonitoringResponseType == MonitoringResponseType.ProvideMasterStateInfo && response.Parameters is MasterStateInfo masterStateInfo)
MasterStateInfo = masterStateInfo;
}
}
}
catch (Exception exception)
{
LastException = exception;
TcpClient?.Close();
TcpClient = null;
}
Thread.Sleep(10*1000);
}
Server code :
while (!StopEvent.WaitOne(WaitTime, true))
{
try
{
if (TcpListener == null)
{
Application.Tracer.Trace(this, TracerEventKind.Info, "Starting TcpListener");
TcpListener = new TcpListener(IPAddress.Any, MasterNetworkServer.MonitoringPort);
TcpListener.Start();
}
if (TcpListener.Pending())
{
Application.Tracer.Trace(this, TracerEventKind.Info, "TcpListener is pending, start processing");
var client = TcpListener.AcceptTcpClient();
var stream = client.GetStream();
stream.WriteTimeout = TimeoutMs;
stream.ReadTimeout = TimeoutMs;
var serialisedDataBuilder = new StringBuilder();
if (stream.DataAvailable)
{
do
{
var bytesRead = stream.Read(BytesBuffer, 0, BytesBuffer.Length);
serialisedDataBuilder.Append(Encoding.UTF8.GetString(BytesBuffer, 0, bytesRead));
} while (stream.DataAvailable);
Application.Tracer.Trace(this, TracerEventKind.Info, "Bytes received");
var requests =
MonitoringRequest.StringToRequests(serialisedDataBuilder.ToString(), distinct: true);
var responses = new List<MonitoringResponse>();
if (requests.Any())
{
Application.Tracer.Trace(this, TracerEventKind.Info,
$"Start to processing {requests.Count} requests");
foreach (var request in requests)
{
responses.Add(HandleMonitoringRequest(request));
Application.Tracer.Trace(this, TracerEventKind.Info, "Response made");
}
Application.Tracer.Trace(this, TracerEventKind.Info, "All responses made");
}
var responsesBytes = MonitoringResponse.ResponsesToBytes(responses);
stream.Write(responsesBytes, 0, responsesBytes.Length);
}
}
}
catch(Exception exception)
{
Application.Tracer.Trace(this, TracerEventKind.Info, $"Monitoring network service exception: {exception.Message}");
}
Thread.Sleep(0);
Avoiding stupid restrictions text.
Avoiding stupid restrictions text.
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The way to fix it was to close stream and client (with method .Close()) after each session and also add some sleep before checking isDataAvailable

TCP/IP listener variable byte length

I have a stream coming in that varies in length but has a start and stop character. When I run this code:
public TCPListener()
{
Int32 port = 31001;
IPAddress localAddr = IPAddress.Parse("192.168.0.78"); //Local
server = new TcpListener(localAddr, port);
server.Start();
while (true)
{
// Console.Write("Waiting for a connection...-- ");
TcpClient client = server.AcceptTcpClient();
// Console.WriteLine("new client connected");
try
{
ThreadPool.QueueUserWorkItem(new WaitCallback(HandleClient), client);
}
catch (Exception ex)
{ }
}
}
private void HandleClient(object tcpClient)
{
// string path = #"c:\Test.txt";
TcpClient client = (TcpClient)tcpClient;
Byte[] bytes = new Byte[135];
String data = null;
int i;
try
{
NetworkStream stream = client.GetStream();
while ((i = stream.Read(bytes, 0, bytes.Length)) != 0)
{
data = System.Text.Encoding.ASCII.GetString(bytes, 0, i);
URLObject oU = new URLObject();
oU = oDecode.TextFrameDecode(data);
Console.WriteLine(data);
Console.WriteLine("");
}
}
catch (Exception ex)
{ }
// Console.WriteLine(data);
}
I get a lot of data every second; I get the data, but it's broken up sometimes into chunks that are not parsable. When I run this code to look for the end delimiter, the feed only get one connection every couple of minutes with only one record so I think the data is getting truncated which is not correct.
static void Main(string[] args)
{
Int32 port = 31001;
IPAddress localAddr = IPAddress.Parse("192.168.0.78"); //Local
server = new TcpListener(localAddr, port);
server.Start();
while (true)
{
Console.Write("Waiting for a connection...-- ");
TcpClient client = server.AcceptTcpClient();
Console.WriteLine("new client connected");
try
{
ThreadPool.QueueUserWorkItem(new WaitCallback(HandleClient), client);
}
catch (Exception ex)
{ }
}
}
static void HandleClient(object tcpClient)
{
TcpClient client = (TcpClient)tcpClient;
Byte[] bytes = new Byte[135];
String data = null;
int i;
try
{
using (NetworkStream stream = client.GetStream())
using (StreamReader reader = new StreamReader(stream))
{
string inputLine = reader.ReadLineSingleBreak();
inputLine = inputLine + "#";
Console.WriteLine(inputLine);
URLObject oU = new URLObject();
oU = oDecode.TextFrameDecode(inputLine);
}
}
catch (Exception ex)
{ }
}
}
public static class StreamReaderExtensions
{
public static string ReadLineSingleBreak(this StreamReader self)
{
StringBuilder currentLine = new StringBuilder();
int i;
char c;
while ((i = self.Read()) >= 0)
{
c = (char)i;
if (c == '#')
{
break;
}
currentLine.Append(c);
}
return currentLine.ToString();
}
}
I need a mix of both... get all the data but then parse it correctly.
I did fix it by Pieter Witvoet advice:
static private TcpListener server = null;
static private Decode oDecode = new Decode();
static private string sLeftOver = string.Empty;
static void Main(string[] args)
{
Int32 port = 31001;
IPAddress localAddr = IPAddress.Parse("192.168.0.78"); //Local
server = new TcpListener(localAddr, port);
server.Start();
while (true)
{
Console.Write("Waiting for a connection...-- ");
TcpClient client = server.AcceptTcpClient();
Console.WriteLine("new client connected");
try
{
ThreadPool.QueueUserWorkItem(new WaitCallback(HandleClient), client);
}
catch (Exception ex)
{ }
}
}
static void HandleClient(object tcpClient)
{
TcpClient client = (TcpClient)tcpClient;
Byte[] bytes = new Byte[256];
String data = null;
int i;
try
{
NetworkStream stream = client.GetStream();
while ((i = stream.Read(bytes, 0, bytes.Length)) != 0)
{
data = System.Text.Encoding.ASCII.GetString(bytes, 0, i);
URLObject oU = new URLObject();
Console.WriteLine(data);
Console.WriteLine("");
//Split data here
string[] aData = Regex.Split(data, #"(?<=[#])");
foreach (string s in aData)
{
string sData = s;
sData = sLeftOver + sData;
if (sData.EndsWith("#"))
{
sLeftOver = string.Empty;
Console.WriteLine(sData);
Console.WriteLine("");
oU = oDecode.TextFrameDecode(sData);
}
else
{
sLeftOver = s;
}
}
}
}
catch (Exception ex)
{ }
}

Async TCPClient missing replies from server

I'm trying to implement an async TCP client that sends messages from a queue and listens to the response.
some of the server replies are lost (for example send 7 messages and get only 4 replies) and I don't understand why.
This is not a server issue, since the synchronize version I tested works just fine.
ConcurrentQueue<byte[]> msgQueue = new ConcurrentQueue<byte[]>();
public void Connect()
{
try
{
tcpclnt = new TcpClient();
Console.WriteLine("Connecting.....");
Task.Factory.StartNew(() =>
{
IAsyncResult res = tcpclnt.BeginConnect(_ip, _port, null, null);
if (!res.AsyncWaitHandle.WaitOne(CONNECTION_TIMEOUT_SEC * 1000))
{
tcpclnt.Close();
throw new ApplicationException("timed out trying to connect");
}
tcpclnt.EndConnect(res);
Receive();
byte[] message = null;
while (true)
{
message = null;
msgQueue.TryDequeue(out message);
if (message != null)
{
Stream stm = tcpclnt.GetStream();
Console.WriteLine("Transmitting..... " + Thread.CurrentThread.ManagedThreadId);//for debug
stm.Write(message.ToArray(), 0, message.ToArray().Length);
Receive();
}
}
});
}
catch (Exception ex)
{
Console.WriteLine(ex.ToString());
}
}
//will be called from outside
public void SendMessage(byte[] msg)
{
Console.WriteLine("SendMessage..... " + Thread.CurrentThread.ManagedThreadId);//for debug
msgQueue.Enqueue(msg);
}
private void Receive()
{
SocketError error;
byte[] buffer = new byte[MAX_BUFFER_SIZE];
tcpclnt.Client.BeginReceive(buffer, 0, MAX_BUFFER_SIZE, SocketFlags.None, out error, new AsyncCallback(ReceiveHandler), buffer);
}
private void ReceiveHandler(IAsyncResult ar)
{
System.Console.WriteLine("ReceiveHandler " + Thread.CurrentThread.ManagedThreadId); //for debug
//End current async receive
int bytesRead = tcpclnt.Client.EndReceive(ar);
byte[] resultBuffer = (byte[]) ar.AsyncState;
// do a lot of things with resultBuffer
}

Respond to a client using a socket?

I have two basic console apps that communicate "over the network" even though all of the communication takes place on my local machine.
Client code:
public static void Main()
{
while (true)
{
try
{
TcpClient client = new TcpClient();
client.Connect("127.0.0.1", 500);
Console.WriteLine("Connected.");
byte[] data = ASCIIEncoding.ASCII.GetBytes(new FeederRequest("test", TableType.Event).GetXmlRequest().ToString());
Console.WriteLine("Sending data.....");
using (var stream = client.GetStream())
{
stream.Write(data, 0, data.Length);
stream.Flush();
Console.WriteLine("Data sent.");
}
client.Close();
Console.ReadLine();
}
catch (Exception e)
{
Console.WriteLine("Error: " + e.StackTrace);
Console.ReadLine();
}
}
}
Server code:
public static void Main()
{
try
{
IPAddress ipAddress = IPAddress.Parse("127.0.0.1");
Console.WriteLine("Starting TCP listener...");
TcpListener listener = new TcpListener(ipAddress, 500);
listener.Start();
Console.WriteLine("Server is listening on " + listener.LocalEndpoint);
while (true)
{
Socket client = listener.AcceptSocket();
Console.WriteLine("\nConnection accepted.");
var childSocketThread = new Thread(() =>
{
Console.WriteLine("Reading data...\n");
byte[] data = new byte[100];
int size = client.Receive(data);
Console.WriteLine("Recieved data: ");
for (int i = 0; i < size; i++)
Console.Write(Convert.ToChar(data[i]));
//respond to client
Console.WriteLine("\n");
client.Close();
Console.WriteLine("Waiting for a connection...");
});
childSocketThread.Start();
}
}
catch (Exception e)
{
Console.WriteLine("Error: " + e.StackTrace);
Console.ReadLine();
}
}
How can I alter both of these applications so that when the Server has received the data, it responds to the Client with some kind of confirmation?
Thanks in advance!
Here a short example how I would do it:
Server:
class Server
{
static void Main(string[] args)
{
TcpListener listener = new TcpListener(IPAddress.Any, 1500);
listener.Start();
TcpClient client = listener.AcceptTcpClient();
NetworkStream stream = client.GetStream();
// Create BinaryWriter for writing to stream
BinaryWriter binaryWriter = new BinaryWriter(stream);
// Creating BinaryReader for reading the stream
BinaryReader binaryReader = new BinaryReader(stream);
while (true)
{
// Read incoming information
byte[] data = new byte[16];
int receivedDataLength = binaryReader.Read(data, 0, data.Length);
string stringData = Encoding.ASCII.GetString(data, 0, receivedDataLength);
// Write incoming information to console
Console.WriteLine("Client: " + stringData);
// Respond to client
byte[] respondData = Encoding.ASCII.GetBytes("respond");
Array.Resize(ref respondData, 16); // Resizing to 16 byte, because in this example all messages have 16 byte to make it easier to understand.
binaryWriter.Write(respondData, 0, 16);
}
}
}
Client:
class Client
{
private static void Main(string[] args)
{
Console.WriteLine("Press any key to start Client");
while (! Console.KeyAvailable)
{
}
TcpClient client = new TcpClient();
client.Connect("127.0.0.1", 1500);
NetworkStream networkStream = client.GetStream();
// Create BinaryWriter for writing to stream
BinaryWriter binaryWriter = new BinaryWriter(networkStream);
// Creating BinaryReader for reading the stream
BinaryReader binaryReader = new BinaryReader(networkStream);
// Writing "test" to stream
byte[] writeData = Encoding.ASCII.GetBytes("test");
Array.Resize(ref writeData, 16); // Resizing to 16 byte, because in this example all messages have 16 byte to make it easier to understand.
binaryWriter.Write(writeData, 0, 16);
// Reading response and writing it to console
byte[] responeBytes = new byte[16];
binaryReader.Read(responeBytes, 0, 16);
string response = Encoding.ASCII.GetString(responeBytes);
Console.WriteLine("Server: " + response);
while (true)
{
}
}
}
I hope this helps! ;)
You can perform both Read and Write on the same stream.
After you send all the data over, just call stream.Read as in
using (var stream = client.GetStream())
{
stream.Write(data, 0, data.Length);
stream.Flush();
Console.WriteLine("Data sent.");
stream.Read(....); //added sync read here
}
MSDN documentation on TcpClient has an example as well http://msdn.microsoft.com/en-us/library/system.net.sockets.tcpclient.aspx
If you want feed back such as reporting # of bytes received so far, you'll have to use async methods.
Here's an example of what (I think) you want to do:
static void Main(string[] args) {
var server = new Task(Server);
server.Start();
System.Threading.Thread.Sleep(10); // give server thread a chance to setup
try {
TcpClient client = new TcpClient();
client.Connect("127.0.0.1", 1500);
Console.WriteLine("Connected.");
var data = new byte[100];
var hello = ASCIIEncoding.ASCII.GetBytes("Hello");
Console.WriteLine("Sending data.....");
using (var stream = client.GetStream()) {
stream.Write(hello, 0, hello.Length);
stream.Flush();
Console.WriteLine("Data sent.");
// You could then read data from server here:
var returned = stream.Read(data, 0, data.Length);
var rec = new String(ASCIIEncoding.ASCII.GetChars(data, 0, data.Length));
rec = rec.TrimEnd('\0');
if (rec == "How are you?") {
var fine = ASCIIEncoding.ASCII.GetBytes("fine and you?");
stream.Write(fine, 0, fine.Length);
}
}
client.Close();
Console.ReadLine();
}
catch (Exception e) {
Console.WriteLine("Error: " + e.StackTrace);
Console.ReadLine();
}
}
public static void Server() {
try {
IPAddress ipAddress = IPAddress.Parse("127.0.0.1");
Console.WriteLine("*Starting TCP listener...");
TcpListener listener = new TcpListener(ipAddress, 1500); // generally use ports > 1024
listener.Start();
Console.WriteLine("*Server is listening on " + listener.LocalEndpoint);
Console.WriteLine("*Waiting for a connection...");
while (true) {
Socket client = listener.AcceptSocket();
while (client.Connected) {
Console.WriteLine("*Connection accepted.");
Console.WriteLine("*Reading data...");
byte[] data = new byte[100];
int size = client.Receive(data);
Console.WriteLine("*Recieved data: ");
var rec = new String(ASCIIEncoding.ASCII.GetChars(data, 0, size));
rec = rec.TrimEnd('\0');
Console.WriteLine(rec);
if (client.Connected == false) {
client.Close();
break;
}
// you would write something back to the client here
if (rec == "Hello") {
client.Send(ASCIIEncoding.ASCII.GetBytes("How are you?"));
}
if (rec == "fine and you?") {
client.Disconnect(false);
}
}
}
listener.Stop();
}
catch (Exception e) {
Console.WriteLine("Error: " + e.StackTrace);
Console.ReadLine();
}
}
}
Keep in mind that data sent via sockets can arrive fragmented (in different packets). This doesn't usually happen with the packets are small.

Socket Programming: Server/Clients and Thread Usage

static void Main(string[] args)
{
Console.Title = "Socket Server";
Console.WriteLine("Listening for client messages");
Socket serverSocket = new Socket(AddressFamily.InterNetwork,
SocketType.Stream,
ProtocolType.Tcp);
IPAddress serverIp = IPAddress.Any;
IPEndPoint serverEP = new IPEndPoint(serverIp, 8000);
SocketPermission socketPermission = new SocketPermission(NetworkAccess.Accept,
TransportType.Tcp,
"127.0.0.1", 8000);
serverSocket.Bind(serverEP);
serverSocket.Listen(2);
while(true)
{
//Socket connection = serverSocket.Accept();
connection = serverSocket.Accept();
Thread clientThread = new Thread(new ParameterizedThreadStart(MultiUser));
clientThread.Start(connection);
}
}
public static void MultiUser(object connection)
{
byte[] serverBuffer = new byte[10025];
string message = string.Empty;
int bytes = ((Socket)connection).Receive(serverBuffer, serverBuffer.Length, 0);
message += Encoding.ASCII.GetString(serverBuffer, 0, bytes);
Console.WriteLine(message);
TcpClient client = new TcpClient();
client.Client = ((Socket)connection);
IntPtr handle = client.Client.Handle;
}
I want to write a chat program which has one server and 2 clients. The problem is that, I can not direct the message sent from the client1 to client2 via the server. How can the server distinguish threads so that it can send the received message from client1 to client2?
Each client has their own handle. You can access this via the Handle property. For example:
TcpClient client = tcpListener.AcceptTcpClient();
IntPtr handle = client.Client.Handle; //returns a handle to the connection
Then all you need to do is store this in a hashtable, and iterate through it, looking for available data. When you detect data on the wire for one of the connections, then save it and retransmit it to the other clients in the table.
Remember to make sure that you make this multithreaded so a listen request on one client does not block any send or receive functions on other clients!
I've added some code here you should be able to work with (tested it out on my system)
private void HandleClients(object newClient)
{
//check to see if we are adding a new client, or just iterating through existing clients
if (newClient != null)
{
TcpClient newTcpClient = (TcpClient)newClient;
//add this client to our list
clientList.Add(newTcpClient.Client.Handle, newTcpClient);
Console.WriteLine("Adding handle: " + newTcpClient.Client.Handle); //for debugging
}
//iterate through existing clients to see if there is any data on the wire
foreach (TcpClient tc in clientList.Values)
{
if (tc.Available > 0)
{
int dataSize = tc.Available;
Console.WriteLine("Received data from: " + tc.Client.Handle); //for debugging
string text = GetNetworkString(tc.GetStream());
//and transmit it to everyone else
foreach (TcpClient otherClient in clientList.Values)
{
if (tc.Client.Handle != otherClient.Client.Handle)
{
Send(otherClient.GetStream(), text);
}
}
}
}
}
public void Send(NetworkStream ns, string data)
{
try
{
byte[] bdata = GetBytes(data, Encoding.ASCII);
ns.Write(bdata, 0, bdata.Length);
}
catch (Exception ex)
{
System.Diagnostics.Debug.WriteLine(ex.Message);
}
}
protected string GetNetworkString(NetworkStream ns)
{
if (ns.CanRead)
{
string receivedString;
byte[] b = GetNetworkData(ns);
receivedString = System.Text.Encoding.UTF8.GetString(b);
log.Info("Received string: " + receivedString);
return receivedString;
}
else
return null;
}
protected byte[] GetNetworkData(NetworkStream ns)
{
if (ns.CanRead)
{
log.Debug("Data detected on wire...");
byte[] b;
byte[] myReadBuffer = new byte[1024];
MemoryStream ms = new MemoryStream();
int numberOfBytesRead = 0;
// Incoming message may be larger than the buffer size.
do
{
numberOfBytesRead = ns.Read(myReadBuffer, 0, myReadBuffer.Length);
ms.Write(myReadBuffer, 0, numberOfBytesRead);
}
while (ns.DataAvailable);
//and get the full message
b = new byte[(int)ms.Length];
ms.Seek(0, SeekOrigin.Begin);
ms.Read(b, 0, (int)ms.Length);
ms.Close();
return b;
}
else
return null;
}
You will want to call HandleClients from a main thread that checks to see if there are any pending requests or not, and runs on a loop.

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