I have one server and client application using socket programming in c#. In this, max. 10 clients can be connected to the server at a time. But my requirement is that I have to block one of the clients via IP address when i'm sending messages through server.. Please help with blocking. The program is given below..
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Net.Sockets;
using System.Net;
namespace Server
{
public partial class SocketServer : Form
{
const int MAX_CLIENTS = 10;
public AsyncCallback pfnWorkerCallBack;
private Socket m_mainSocket;
private Socket[] m_workerSocket = new Socket[10];
private int m_clientCount = 0;
private byte[] byData;
public SocketServer()
{
InitializeComponent();
textBoxIP.Text = GetIP();
}
String GetIP()
{
String strHostName = Dns.GetHostName();
// Find host by name
IPHostEntry iphostentry = Dns.GetHostByName(strHostName);
// Grab the first IP addresses
String IPStr = "";
foreach (IPAddress ipaddress in iphostentry.AddressList)
{
IPStr = ipaddress.ToString();
ip = IPStr;
return IPStr;
}
ip = IPStr;
return IPStr;
}
private void Form1_Load(object sender, EventArgs e)
{
}
private void buttonStartListen_Click(object sender, EventArgs e)
{
try
{
// Check the port value
if (textBoxPort.Text == "")
{
MessageBox.Show("Please enter a Port Number");
return;
}
string portStr = textBoxPort.Text;
int port = System.Convert.ToInt32(portStr);
// Create the listening socket...
m_mainSocket = new Socket(AddressFamily.InterNetwork,
SocketType.Stream,
ProtocolType.Tcp);
IPEndPoint ipLocal = new IPEndPoint(IPAddress.Any, port);
// Bind to local IP Address...
m_mainSocket.Bind(ipLocal);
// Start listening...
m_mainSocket.Listen(4);
// Create the call back for any client connections...
m_mainSocket.BeginAccept(new AsyncCallback(OnClientConnect), null);
UpdateControls(true);
}
catch (SocketException se)
{
MessageBox.Show(se.Message);
}
}
private void UpdateControls(bool listening)
{
buttonStartListen.Enabled = !listening;
buttonStopListen.Enabled = listening;
}
public delegate void UpdateTextCallback(string message, object obj);
public void OnClientConnect(IAsyncResult asyn)
{
try
{
// Here we complete/end the BeginAccept() asynchronous call
// by calling EndAccept() - which returns the reference to
// a new Socket object
m_workerSocket[m_clientCount] = m_mainSocket.EndAccept(asyn);
// Let the worker Socket do the further processing for the
// just connected client
WaitForData(m_workerSocket[m_clientCount]);
// Now increment the client count
++m_clientCount;
// Display this client connection as a status message on the GUI
String str = String.Format("Client # {0} connected", m_clientCount);
//textBoxMsg.Text = str;
textBoxMsg.BeginInvoke(new UpdateTextCallback(UpdateText), new object[] { str, textBoxMsg });
// Since the main Socket is now free, it can go back and wait for
// other clients who are attempting to connect
m_mainSocket.BeginAccept(new AsyncCallback(OnClientConnect), null);
}
catch (ObjectDisposedException)
{
System.Diagnostics.Debugger.Log(0, "1", "\n OnClientConnection: Socket has been closed\n");
}
catch (SocketException se)
{
MessageBox.Show(se.Message);
}
}
private void UpdateText(string message, object ctrl)
{
if (ctrl is TextBox)
textBoxMsg.Text = message;
if(ctrl is RichTextBox)
richTextBoxReceivedMsg.AppendText(message);
}
public class SocketPacket
{
public System.Net.Sockets.Socket m_currentSocket;
public byte[] dataBuffer = new byte[1];
}
public void WaitForData(System.Net.Sockets.Socket soc)
{
try
{
if (pfnWorkerCallBack == null)
{
// Specify the call back function which is to be
// invoked when there is any write activity by the
// connected client
pfnWorkerCallBack = new AsyncCallback(OnDataReceived);
}
SocketPacket theSocPkt = new SocketPacket();
theSocPkt.m_currentSocket = soc;
// Start receiving any data written by the connected client
// asynchronously
soc.BeginReceive(theSocPkt.dataBuffer, 0,
theSocPkt.dataBuffer.Length,
SocketFlags.None,
pfnWorkerCallBack,
theSocPkt);
}
catch (SocketException se)
{
MessageBox.Show(se.Message);
}
}
public void OnDataReceived(IAsyncResult asyn)
{
try
{
SocketPacket socketData = (SocketPacket)asyn.AsyncState;
int iRx = 0;
// Complete the BeginReceive() asynchronous call by EndReceive() method
// which will return the number of characters written to the stream
// by the client
iRx = socketData.m_currentSocket.EndReceive(asyn);
char[] chars = new char[iRx + 1];
System.Text.Decoder d = System.Text.Encoding.UTF8.GetDecoder();
int charLen = d.GetChars(socketData.dataBuffer,
0, iRx, chars, 0);
System.String szData = new System.String(chars);
//richTextBoxReceivedMsg.AppendText(szData);
richTextBoxReceivedMsg.BeginInvoke(new UpdateTextCallback(UpdateText), new object[] { szData, richTextBoxReceivedMsg });
// Continue the waiting for data on the Socket
WaitForData(socketData.m_currentSocket);
}
catch (ObjectDisposedException)
{
System.Diagnostics.Debugger.Log(0, "1", "\nOnDataReceived: Socket has been closed\n");
}
catch (SocketException se)
{
MessageBox.Show(se.Message);
}
}
private void buttonStopListen_Click(object sender, EventArgs e)
{
CloseSockets();
UpdateControls(false);
}
void CloseSockets()
{
if (m_mainSocket != null)
{
m_mainSocket.Close();
}
for (int i = 0; i < m_clientCount; i++)
{
if (m_workerSocket[i] != null)
{
m_workerSocket[i].Close();
m_workerSocket[i] = null;
}
}
}
private void buttonSendMsg_Click(object sender, EventArgs e)
{
try
{
Object objData = richTextBoxSendMsg.Text;
byData = System.Text.Encoding.ASCII.GetBytes(objData.ToString());
for (int i = 0; i < m_clientCount; i++)
{
if (m_workerSocket[i] != null)
{
if (m_workerSocket[i].Connected)
{
m_workerSocket[i].Send(byData);
}
}
}
}
catch (SocketException se)
{
MessageBox.Show(se.Message);
}
}
private void Form1_Minimize(object sender, System.EventArgs e)
{
if (FormWindowState.Minimized == WindowState)
{
Hide();
this.notify.Visible = true;
}
}
private void Form1_Resize(object sender, System.EventArgs e)
{
Show();
WindowState = FormWindowState.Normal;
this.notify.Visible = false;
}
This is somewhat easy to do, you just need to look a little more at the client connection routine... Replace the 127.0.0.1 below with the IP address you want to deny and throw an exception or simply close the connection and return.
public void OnClientConnect(IAsyncResult asyn)
{
try
{
TcpListener listener = (TcpListener)ar.AsyncState;
System.Net.Sockets.TcpClient client = listener.EndAcceptTcpClient(ar);
IPEndPoint clientEndPoint = (IPEndPoint)client.Client.RemoteEndPoint;
if (clientEndPoint.Address == new IPAddress("127.0.0.1"))
throw new InvalidOperationException();
Related
So my homework is to write a POP3 messaging software using tcp packets and im not allowed to use external libraries. I start the tcp connection when i press the Connect button and i also have a Disconnect button which stops it. I tested my server program with PuTTY and it works fine after the first connection but when i press Disconnect and Connect again it doesnt print the received data to the monitor. This problem is bothering me for ages please help. Here is my code:
Edit:
The problem was that i dont quite understand how threads work and i didnt create a new thread for each connection so i instantiated a new thread every time i created a new listener.
namespace POP3Server
{
public partial class MainWindow : Window
{
private TcpListener server;
private Int32 port;
private IPAddress ipAddress;
private TcpClient client;
private Logger log;
private Thread tcpAcceptThread;
private bool serverStarted;
public MainWindow()
{
InitializeComponent();
log = new Logger(txtConsole);
serverStarted = false;
tcpAcceptThread = new Thread(GetData);
}
private void btnConnect_Click(object sender, RoutedEventArgs e)
{
try
{
port = Convert.ToInt32(txtPort.Text);
ipAddress = IPAddress.Parse(txtIP.Text);
server = new TcpListener(ipAddress, port);
server.Start();
if (tcpAcceptThread.ThreadState != ThreadState.Unstarted)
tcpAcceptThread.Start();
serverStarted = true;
log.WriteLine("Server started!");
btnConnect.IsEnabled = false;
btnDisconnect.IsEnabled = true;
}
catch (Exception ex)
{
log.WriteLine(ex.ToString());
}
}
private void btnDisconnect_Click(object sender, RoutedEventArgs e)
{
try
{
if (client != null)
client.Close();
server.Stop();
log.WriteLine("Server stopped!");
serverStarted = false;
btnConnect.IsEnabled = true;
btnDisconnect.IsEnabled = false;
}
catch (Exception ex)
{
log.WriteLine(ex.ToString());
}
}
private void GetData()
{
try
{
while (serverStarted)
{
client = server.AcceptTcpClient();
this.Dispatcher.Invoke(() => log.WriteLine("Connected!"));
Byte[] bytes = new Byte[256];
String data = null;
NetworkStream stream = client.GetStream();
int i;
// Loop to receive all the data sent by the client.
while ((i = stream.Read(bytes, 0, bytes.Length)) != 0)
{
// Translate data bytes to a ASCII string.
data = System.Text.Encoding.ASCII.GetString(bytes, 0, i);
this.Dispatcher.Invoke(() => log.WriteLine("Received: " + data));
}
}
}
catch (Exception ex)
{
this.Dispatcher.Invoke(() => log.WriteLine(ex.ToString()));
}
}
private void btnClear_Click(object sender, RoutedEventArgs e)
{
log.Clear();
}
}
}
Could you change following code
private bool serverStarted;
to:
private object _someLockObject = new object();
private bool _serverStarted = false;
private bool serverStarted {
get {
lock (_someLockObject)
{
return _serverStarted;
}
}
set {
lock (_someLockObject)
{
_serverStarted = value;
}
}
};
My first hunch is boolean property is not updated.
I wrote a chat application in C# WinForms. But if I close the client form (while this form is connected to the server form) and reopen the client form and try to reconnect, the client doesn't connect to the server..
How can I reconnect the client to the server if the application is closed and reopened?
(sorry for bad english)
Server:
public frmServer()
{
InitializeComponent();
textBox_Hostname.Text = GetLocalIPAddress();
Configuration Programmkonfiguration = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
Port = Programmkonfiguration.AppSettings.Settings["Port"].Value;
textBox_Port.Text = Port;
toolStripStatusLabel_Serverstatus.Text = "deaktiviert";
toolStripStatusLabel_Serverstatus.ForeColor = Color.Red;
textBox_Output.Focus();
}
private string GetLocalIPAddress()
{
var host = Dns.GetHostEntry(Dns.GetHostName());
foreach (var ip in host.AddressList)
{
if (ip.AddressFamily == AddressFamily.InterNetwork)
{
return ip.ToString();
}
}
throw new Exception("No network adapters with an IPv4 address in the system!");
}
private void button_Send_Click(object sender, EventArgs e)
{
if (!(string.IsNullOrWhiteSpace(textBox_Output.Text)))
{
String s = "Server: " + textBox_Output.Text + Environment.NewLine;
textBox_Input.Text += s;
byte[] byteTime = Encoding.ASCII.GetBytes(s);
ns.Write(byteTime, 0, byteTime.Length);
textBox_Output.Clear();
}
}
public void DoWork()
{
byte[] bytes = new byte[1024];
while (true)
{
int bytesRead = ns.Read(bytes, 0, bytes.Length);
this.SetText(Encoding.ASCII.GetString(bytes, 0, bytesRead));
}
}
private void SetText(string text)
{
if (this.textBox_Input.InvokeRequired)
{
SetTextCallback d = new SetTextCallback(SetText);
this.Invoke(d, new object[] { text });
}
else
{
this.textBox_Input.Text = this.textBox_Input.Text + text;
}
}
private void button_Starten_Click(object sender, EventArgs e)
{
IPAddress hostname = IPAddress.Parse(textBox_Hostname.Text);
int portNum = Convert.ToInt32(textBox_Port.Text);
listener = new TcpListener(hostname, portNum);
listener.Start();
Task TCPListener = new Task(() => AcceptTCP());
TCPListener.Start();
textBox_Input.Text += "Server gestartet." + Environment.NewLine;
button_Starten.Enabled = false;
toolStripStatusLabel_Serverstatus.Text = "aktiviert";
toolStripStatusLabel_Serverstatus.ForeColor = Color.Green;
}
private void AcceptTCP()
{
client = listener.AcceptTcpClient();
ns = client.GetStream();
Task Work = new Task(() => DoWork());
Work.Start();
}
private void textBox_Output_KeyDown(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Enter)
{
button_Send_Click(sender, e);
e.Handled = true;
textBox_Output.Focus();
}
}
}
Client:
public frmClient()
{
InitializeComponent();
Configuration Programmkonfiguration = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
HostnameServer = Programmkonfiguration.AppSettings.Settings["HostnameServer"].Value;
Port = Programmkonfiguration.AppSettings.Settings["Port"].Value;
textBox_Hostname.Text = GetLocalIPAddress();
textBox_Port.Text = Port;
toolStripStatusLabel_Status.Text = " nicht verbunden";
toolStripStatusLabel_Status.ForeColor = Color.Red;
textBox_Output.Focus();
}
private string GetLocalIPAddress()
{
var host = Dns.GetHostEntry(HostnameServer);
foreach (var ip in host.AddressList)
{
if (ip.AddressFamily == AddressFamily.InterNetwork)
{
return ip.ToString();
}
}
throw new Exception("No network adapters with an IPv4 address in the system!");
}
private void button_Senden_Click(object sender, EventArgs e)
{
if (!(string.IsNullOrWhiteSpace(textBox_Output.Text)))
{
String s = "Client: " + textBox_Output.Text + Environment.NewLine;
textBox_Input.Text += s;
byte[] byteTime = Encoding.ASCII.GetBytes(s);
ns.Write(byteTime, 0, byteTime.Length);
textBox_Output.Clear();
}
}
public void DoWork()
{
byte[] bytes = new byte[1024];
while (true)
{
if (ns.DataAvailable)
{
int bytesRead = ns.Read(bytes, 0, bytes.Length);
this.SetText(Encoding.ASCII.GetString(bytes, 0, bytesRead));
}
}
}
private void SetText(string text)
{
if (this.textBox_Input.InvokeRequired)
{
SetTextCallback d = new SetTextCallback(SetText);
this.Invoke(d, new object[] { text });
}
else
{
this.textBox_Input.Text = this.textBox_Input.Text + text;
}
}
private void button_Connect_Click(object sender, EventArgs e)
{
string hostName = textBox_Hostname.Text;
int portNum = Convert.ToInt32(textBox_Port.Text);
client = new TcpClient(hostName, portNum);
ns = client.GetStream();
Work = new Task(() => DoWork());
Work.Start();
textBox_Input.Text += "Verbindung hergestellt." + Environment.NewLine;
button_Connect.Enabled = false;
toolStripStatusLabel_Status.Text = "verbunden";
toolStripStatusLabel_Status.ForeColor = Color.Green;
}
private void textBox_Output_KeyDown(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Enter)
{
button_Senden_Click(sender, e);
e.Handled = true;
textBox_Output.Focus();
}
}
}
Each call to Accept on a listener socket accepts a single connection. At the moment, your server accepts a single connection request and then ignores the listener socket from that point onwards.
Normally, you'd want some form of "Accept loop" that continually calls Accept, sets up the server side resources for that connection and then loops back to call Accept again.
E.g. the trivial change is to do this:
private void AcceptTCP()
{
while(true)
{
client = listener.AcceptTcpClient();
ns = client.GetStream();
Task Work = new Task(() => DoWork());
Work.Start();
}
}
But now you really have to think about what happens to ns - what happens if/when you want a second client connected simultaneously? Having NetworkStream be a single shared instance variable within the server isn't going to scale well.
Normally, you'd want to create some form of simple class that represents each connection + your server specific information relating to that connection. E.g. it would contain the NetworkStream, the current "state" of this connection (if you have modes or states), possibly the buffers that were last passed to a Read call as/when you start going async with this work, etc.
I want to get tcp client ip address and port but I can't to do that.I want to use socket in my code except tcp listener class and my goal is get client ip and port without this class. below is my code:(I want to get client ip address and port before if(rc){} condition)
namespace Example
{
public partial class TCP_Server : Form
{
Socket socketServer = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
Socket socketClient = null;
public TCP_Server()
{
InitializeComponent();
CheckForIllegalCrossThreadCalls = false;
}
private void Form1_Load(object sender, EventArgs e)
{
}
public void start()
{
IPEndPoint ipens = new IPEndPoint(IPAddress.Parse(txt_ip.Text), int.Parse(txt_port.Text));
socketServer.Bind(ipens);
MessageBox.Show("wait");
while (true)
{
socketServer.Listen(2);
socketClient = socketServer.Accept();
MessageBox.Show("accept");
Thread trgetmsg = new Thread(new ThreadStart(getmsg));
trgetmsg.Start();
}
}
public void getmsg()
{
int counter = 0;
string[] barray2 = new string[10];
try
{
while (true)
{
byte[] barray = new byte[1024];
EndPoint iprec = new IPEndPoint(IPAddress.Parse("127.0.0.1"), 4040);
int rc = socketClient.ReceiveFrom(barray , ref iprec);
barray2[counter] = Encoding.Unicode.GetString(barray, 0, rc);
counter =counter+1;
if (rc > 0)
{
MessageBox.Show(iprec.);
if (barray2[0] == barray2[1])
{
listBox1.Items.Add("client: " + Encoding.Unicode.GetString(barray, 0, rc));
socketClient.Send(Encoding.Unicode.GetBytes(barray2[0]));
}
}
}
}
catch { ;}
}
This will provide endpoint info of accepted client;
socketClient = socketServer.Accept();
var endPoint = (IPEndPoint)socketClient.RemoteEndPoint;
This is my scenario:
Client :
Send xml data in pieces continuously 24/7 - (It is working fine and it is not in my control).
Server - My Code:
1. Listen continuously.
2. Receive the incoming message, buffer it and create valid xml from buffer.
3. Send it to the MSMQ ( Host will do this )
I wrote a tcp server code (adding pieces of code from google), which will be hosted in windows service. Everything works fine when I run the service in local but when I place it PROD, it listens upto 73K messages and it stops receiving. It is not throwing any exception. It just blocks at BeginReceive function. I have tried using ReceiveTimeOut also. I have seen netstat also and the connections is still in established stat.
When I restart the service, it again works fine. Here I am posting my server code. Please help on this.
StringBuilder content = new StringBuilder();
public event MessageReceiveEventHandler MessageReceived;
// An ArrayList is used to keep track of worker sockets that are designed
// to communicate with each connected client. Make it a synchronized ArrayList
// For thread safety
private System.Collections.ArrayList workerSocketList =
ArrayList.Synchronized(new System.Collections.ArrayList());
private int m_clientCount = 0;
private Socket m_mainSocket = null;
private AsyncCallback ReadCallback;
private AsyncCallback ConnectionCallback;
public MedDeviceListener(string ipAddress, int port, int maxConnections=100)
{
ProfileProvider.Instance.LogInformationIf(_debug);
this._port = port;
this._ipAddress = ipAddress;
this._maxConnections = maxConnections;
ReadCallback = new AsyncCallback(Receive_handler);
ConnectionCallback = new AsyncCallback(Connection_handler);
lenghtofStartMsg = header.Length;
lengthOfEndMsg = footer.Length;
}
public void Start()
{
ProfileProvider.Instance.LogInformationIf(_debug);
// Data buffer for incoming data.
byte[] bytes = new Byte[_bufferSize];
// Establish the local endpoint for the socket.
IPEndPoint localEndPoint = new IPEndPoint(IPAddress.Parse(_ipAddress), _port);
// Create a TCP/IP socket.
m_mainSocket = new Socket(AddressFamily.InterNetwork,
SocketType.Stream, ProtocolType.Tcp);
// Bind the socket to the local endpoint and listen for incoming connections.
try
{
m_mainSocket.Bind(localEndPoint);
m_mainSocket.Listen(100);
InstrumentationProvider.Instance.LogInformation("MedDeviceListener successfully connected to IP:" + _ipAddress+"\nPort :"+_port);
m_mainSocket.BeginAccept(ConnectionCallback, m_mainSocket);
}
catch (Exception e)
{
InstrumentationProvider.Instance.LogException("MedDeviceListener.Start", e);
throw e;
}
}
private void Connection_handler(IAsyncResult ar)
{
try
{
ProfileProvider.Instance.LogInformationIf(_debug);
Socket listener = (Socket)ar.AsyncState;
Socket workerSocket = listener.EndAccept(ar);
// Now increment the client count for this client
// in a thread safe manner
Interlocked.Increment(ref m_clientCount);
// Add the workerSocket reference to our ArrayList
workerSocketList.Add(workerSocket);
SendConnectedAck(_clientConnectAckMessage, m_clientCount);
WaitForData(workerSocket, m_clientCount);
//Resume the listening callback loop
listener.BeginAccept(Connection_handler, listener);
}
catch (ObjectDisposedException)
{
InstrumentationProvider.Instance.LogInformation("The listener socket has been closed");
}
catch (Exception ex)
{
InstrumentationProvider.Instance.LogException("Connection_handler", ex);
throw;
}
}
private void Receive_handler(IAsyncResult ar)
{
ProfileProvider.Instance.LogInformationIf(_debug);
StateObject state = (StateObject)ar.AsyncState;
try
{
// Retrieve the state object and the handler socket
// from the asynchronous state object.
Socket workSocket = state.workSocket;
// Read data from the client socket.
int bytesRead = workSocket.EndReceive(ar);
if (bytesRead > 0)
{
//InstrumentationProvider.Instance.LogInformationIf(_debug, bytesRead+" read..");
// There might be more data, so parse the data received so far.
string data= Encoding.ASCII.GetString(state.buffer, 0, bytesRead);
try
{
ParseIncomingMessage(data, workSocket);
}
catch(Exception parseEx)
{
content.Clear();
InstrumentationProvider.Instance.LogException("ParseIncomingMessage", parseEx);
}
}
WaitForData(state.workSocket, state.clientNumber);
}
catch (ObjectDisposedException)
{
InstrumentationProvider.Instance.LogInformation("Receive_handler: The listener socket has been closed");
}
catch (SocketException se)
{
//close the existing connection
CloseSockets();
//restart it again
this.Start();
}
}
private void WaitForData(Socket workerSocket, int clientNumber)
{
ProfileProvider.Instance.LogInformationIf(_debug);
try
{
StateObject theSocPkt = new StateObject(workerSocket, clientNumber);
workerSocket.ReceiveTimeout = 2000;
workerSocket.BeginReceive(theSocPkt.buffer, 0,
theSocPkt.buffer.Length,
SocketFlags.None,
Receive_handler,
theSocPkt);
}
catch(TimeoutException ex)
{
InstrumentationProvider.Instance.LogException("WaitForData - TimeOutException", ex);
}
catch (SocketException se)
{
InstrumentationProvider.Instance.LogException("MedDeviceListener.WaitForData", se);
//close the existing connection
CloseSockets();
//restart it again
this.Start();
}
catch (Exception ex)
{
InstrumentationProvider.Instance.LogException("WaitForData",ex);
//close the existing connection
CloseSockets();
//restart it again
this.Start();
}
}
private void ParseIncomingMessage(string msg,Socket wrkSocket)
{
Socket workSocket = wrkSocket;
bool hasStartTag = isMsgContainsStartTag(msg);
bool hasEndTag = isMsgContainsEndTag(msg);
int startTagIndex = indexOfStartTag(msg);
int endTagIndex = indexOfEndTag(msg);
// If the incomming message dont have either start or end tag
if (hasStartTag == false && hasEndTag == false)
{
content.Append(msg);
}
//check for the starttag first
//if message contains startTag
else if (hasStartTag)
{
if (startTagIndex != 0)//there is something before starttag
{
string subStr = msg.Substring(0, startTagIndex);
content.Append(subStr);
//Check and send the content
CheckSendMessage(workSocket);
//Parse the remaining message from start tag to end of the message
ParseIncomingMessage(msg.Substring(startTagIndex, msg.Length - subStr.Length), wrkSocket);
}
else if (startTagIndex == 0)
{
content.Clear();
if (hasEndTag)
{
int endOfEndTag = endTagIndex + lengthOfEndMsg;
string subStr = msg.Substring(0, endOfEndTag); //message statrs with start tag and ends contains full end tag so first get that string and send that.
content.Append(subStr);
CheckSendMessage(workSocket);
//Parse the remaining message from endtag+1 to end
ParseIncomingMessage(msg.Substring(endOfEndTag, msg.Length - endOfEndTag), wrkSocket);
}
else
{
content.Append(msg);
}
}
}
//if message contains EndTag ALONE
else if (hasEndTag)
{
int endOfEndTag = endTagIndex + lengthOfEndMsg;
string subStr = msg.Substring(0, endOfEndTag);
content.Append(subStr);
CheckSendMessage(workSocket);
//Parse remaining message after end tag
ParseIncomingMessage(msg.Substring(endOfEndTag, msg.Length - endOfEndTag), wrkSocket);
}
}
private void CheckSendMessage(Socket workSocket)
{
string msg=content.ToString().Trim();
//if content contains both start and end tag then send the content
if (isMsgContainsStartTag(msg) && isMsgContainsEndTag(msg) &&
indexOfStartTag(msg) == 0 && indexOfEndTag(msg) + lengthOfEndMsg == msg.Length)
{
//Send the message
using (MedDeviceListenerEventArgs e = new MedDeviceListenerEventArgs(msg))
{
OnReceiveComplete(e);
SendReceiveAck(workSocket, _receiveAckMessage);
}
}
}
private void SendReceiveAck(Socket handler, String data)
{
try
{
ProfileProvider.Instance.LogInformationIf(_debug);
// Convert the string data to byte data using ASCII encoding.
byte[] byteData = Encoding.ASCII.GetBytes(data);
handler.Send(byteData);
InstrumentationProvider.Instance.LogInformationIf(_debug, "Message received acknowledgement:" + _receiveAckMessage + " has been sent successfully");
}
catch (Exception ex)
{
InstrumentationProvider.Instance.LogException("SendReceiveAck", ex);
}
}
private void SendConnectedAck(string msg, int clientNumber)
{
ProfileProvider.Instance.LogInformationIf(_debug);
try
{
// Convert the reply to byte array
byte[] byData = System.Text.Encoding.ASCII.GetBytes(msg);
Socket workerSocket = (Socket)workerSocketList[clientNumber - 1];
workerSocket.Send(byData);
InstrumentationProvider.Instance.LogInformationIf(_debug, "Client Connected acknowledgement:" + _clientConnectAckMessage + " has been sent successfully");
}
catch (Exception ex)
{
InstrumentationProvider.Instance.LogException("SendConnectedAck", ex);
throw;
}
}
public void CloseSockets()
{
try
{
ProfileProvider.Instance.LogInformationIf(_debug);
if (m_mainSocket != null)
{
if (m_mainSocket.Connected)
{
m_mainSocket.Shutdown(SocketShutdown.Both);
m_mainSocket.Close();
m_mainSocket = null;
}
}
Socket workerSocket = null;
for (int i = 0; i < workerSocketList.Count; i++)
{
workerSocket = (Socket)workerSocketList[i];
if (workerSocket != null)
{
workerSocket.Shutdown(SocketShutdown.Both);
workerSocket.Close();
workerSocket = null;
}
}
}
catch(Exception ex)
{
InstrumentationProvider.Instance.LogException("CloseSockets",ex);
}
}
protected virtual void OnReceiveComplete(MedDeviceListenerEventArgs e)
{
if (MessageReceived != null)
{
MessageReceived(this, e);
}
}
private int indexOfStartTag(string msg)
{
return msg.IndexOf(header);
}
private int indexOfEndTag(string msg)
{
return msg.IndexOf(footer);
}
private bool isMsgContainsStartTag(string msg)
{
return msg.Contains(header);
}
private bool isMsgContainsEndTag(string msg)
{
return msg.Contains(footer);
}
public delegate void MessageReceiveEventHandler(object sender,MedDeviceListenerEventArgs e);
public class MedDeviceListenerEventArgs : EventArgs,IDisposable
{
private string _receivedData;
public MedDeviceListenerEventArgs(string receivedData)
{
_receivedData = receivedData;
}
public string ReceivedData
{
get
{
return _receivedData;
}
}
public void Dispose()
{ }
}
}
I have read similar posts, tried everything but with no luck. Please help :)
Thanks
-MM
can someone please help me out with this... I've been struggling all day.
So I'm trying to learn Async sockets which is something that's been giving me trouble.
The issue is basically the way I'm updating the ListBox with people who have joined the chat room's names:
Basically what I'm doing is having each client send "!!addlist [nickname]" when they join the server.
It's not ideal as it doesn't check for duplicates etc. but now I just want to know why it won't work.
Whenever somebody adds a name they haven't seen before, they will also send "!!addlist [nick]"
In this way, every time someone joins, the lists should be updated for everyone.
The issue seems to be that all the clients start communicating at the same time and it interferes with the buffer.
I've tried using a separate buffer for every client so that's not the issue.
I've tried using lock() but that doesn't seem to be working either.
Essentially what happens is the buffers seem to truncate; where there is data from two different people in the same buffer.
Please just tell me what I'm doing wrong with the buffers or on the client side:
Note that the async socket is using Send instead of BeginSend.
I've tried both methods and they run into the same issue... so it's probably client side?
public partial class Login : Form
{
private ChatWindow cw;
private Socket serverSocket;
private List<Socket> socketList;
private byte[] buffer;
private bool isHost;
private bool isClosing;
public void startListening()
{
try
{
this.isHost = true; //We're hosting this server
cw.callingForm = this; //Give ChatForm the login form (this) [that acts as the server]
cw.Show(); //Show ChatForm
cw.isHost = true; //Tell ChatForm it is the host (for display purposes)
this.Hide(); //And hide the login form
serverSocket.Bind(new IPEndPoint(IPAddress.Any, int.Parse(portBox.Text))); //Bind to our local address
serverSocket.Listen(1); //And start listening
serverSocket.BeginAccept(new AsyncCallback(AcceptCallback), null); //When someone connects, begin the async callback
cw.connectTo("127.0.0.1", int.Parse(portBox.Text), nicknameBox.Text); //And have ChatForm connect to the server
}
catch (Exception) { /*MessageBox.Show("Error:\n\n" + e.ToString());*/ } //Let us know if we ran into any errors
}
public void AcceptCallback(IAsyncResult AR)
{
try
{
Socket s = serverSocket.EndAccept(AR); //When someone connects, accept the new socket
socketList.Add(s); //Add it to our list of clients
s.BeginReceive(buffer, 0, buffer.Length, SocketFlags.None, new AsyncCallback(ReceiveCallback), s); //Begin the async receive method using our buffer
serverSocket.BeginAccept(new AsyncCallback(AcceptCallback), null); //And start accepting new connections
}
catch (Exception) {}
}
public void ReceiveCallback(IAsyncResult AR) //When a message from a client is received
{
try
{
if (isClosing)
return;
Socket s = (Socket)AR.AsyncState; //Get the socket from our IAsyncResult
int received = s.EndReceive(AR); //Read the number of bytes received (*need to add locking code here*)
byte[] dbuf = new byte[received]; //Create a temporary buffer to store just what was received so we don't have extra data
Array.Copy(buffer, dbuf, received); //Copy the received data from our buffer to our temporary buffer
foreach (Socket client in socketList) //For each client that is connected
{
try
{
if (client != (Socket)AR.AsyncState) //If this isn't the same client that just sent a message (*client handles displaying these*)
client.Send(dbuf); //Send the message to the client
}
catch (Exception) { }
} //Start receiving new data again
s.BeginReceive(buffer, 0, buffer.Length, SocketFlags.None, new AsyncCallback(ReceiveCallback), s);
}
catch (Exception) { /*cw.output("\n\nError:\n\n" + e.ToString());*/ }
}
public void SendCallback(IAsyncResult AR)
{
try
{
Socket s = (Socket)AR.AsyncState;
s.EndSend(AR);
}
catch (Exception) { /*cw.output("\n\nError:\n\n" + e.ToString());*/ }
}
Here is the client side:
public void getData()
{
try
{
byte[] buf = new byte[1024];
string message = "";
while(isConnected)
{
Array.Clear(buf, 0, buf.Length);
message = "";
clientSocket.Receive(buf, buf.Length, SocketFlags.None);
message = Encoding.ASCII.GetString(buf);
if (message.StartsWith("!!addlist"))
{
message = message.Replace("!!addlist", "");
string userNick = message.Trim();
if (!namesBox.Items.Contains(userNick))
{
addNick(userNick.Trim());
}
continue;
}
else if (message.StartsWith("!!removelist"))
{
message = message.Replace("!!removelist", "");
string userNick = message.Trim();
removeNick(userNick);
output("Someone left the room: " + userNick);
continue;
}
else if (!namesBox.Items.Contains(message.Substring(0, message.IndexOf(":"))))
{
addNick(message.Substring(0, message.IndexOf(":")).Trim()); //So they at least get added when they send a message
}
output(message);
}
}
catch (Exception)
{
output("\n\nConnection to the server lost.");
isConnected = false;
}
}
Here is my addNick function that seems to fix some things?
public void addNick(string n)
{
if (n.Contains(" ")) //No Spaces... such a headache
return;
if (n.Contains(":"))
return;
bool shouldAdd = true;
n = n.Trim();
for (int x = namesBox.Items.Count - 1; x >= 0; --x)
if (namesBox.Items[x].ToString().Contains(n))
shouldAdd = false;
if (shouldAdd)
{
namesBox.Items.Add(n);
output("Someone new joined the room: " + n);
sendRaw("!!addlist " + nickName);
}
}
I think the issue is that some of the packets are being skipped?
Maybe there's too much code in the client after Receive before it gets called again?
Should I create a separate thread for each message so that receive runs constantly? (Dumb)
Should I have my client use Async receives and sends as well?
I have a feeling that is the answer ^
With all of the checks I do, I managed to clean up the duplicate name issue... but i regularly receive messages with spaces and partial messages from other clients it seems.
Okay so, after messing with this for a long time, I have it relatively stable.
For starters, I added the following state object:
public class StateObject
{
public Socket workSocket = null;
public const int BufferSize = 1024;
public byte[] buffer = new byte[BufferSize];
public StringBuilder sb = new StringBuilder();
public bool newConnection = true;
}
This makes it easy to keep track of each connection and gives each connection its own buffer.
The second thing I did was look for a new line in each message.
I wasn't looking for this in the original code and I believe this was the root of most issues.
I also gave the responsibility of dealing with username management to the server; something that I should have done from the start obviously.
Here is the current server code:
This code is in no way perfect and I'm continuously finding new errors the more I try to break it. I'm going to keep messing with it for awhile but at the moment, it seems to work decently.
public partial class Login : Form
{
private ChatWindow cw;
private Socket serverSocket;
private List<Socket> socketList;
private byte[] buffer;
private bool isHost;
private bool isClosing;
private ListBox usernames;
public Login()
{
InitializeComponent();
}
private void Login_Load(object sender, EventArgs e)
{
ipLabel.Text = getLocalIP();
cw = new ChatWindow();
serverSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
socketList = new List<Socket>();
buffer = new byte[1024];
isClosing = false;
usernames = new ListBox();
}
public string getLocalIP()
{
return Dns.GetHostEntry(Dns.GetHostName()).AddressList.FirstOrDefault(ip => ip.AddressFamily == AddressFamily.InterNetwork).ToString();
}
private void joinButton_Click(object sender, EventArgs e)
{
try
{
int tryPort = 0;
this.isHost = false;
cw.callingForm = this;
if (ipBox.Text == "" || portBox.Text == "" || nicknameBox.Text == "" || !int.TryParse(portBox.Text.ToString(), out tryPort))
{
MessageBox.Show("You must enter an IP Address, Port, and Nickname to connect to a server.", "Missing Info");
return;
}
this.Hide();
cw.Show();
cw.connectTo(ipBox.Text, int.Parse(portBox.Text), nicknameBox.Text);
}
catch(Exception otheree) {
MessageBox.Show("Error:\n\n" + otheree.ToString(),"Error connecting...");
cw.Hide();
this.Show();
}
}
private void hostButton_Click(object sender, EventArgs e)
{
int tryPort = 0;
if (portBox.Text == "" || nicknameBox.Text == "" || !int.TryParse(portBox.Text.ToString(), out tryPort)) {
MessageBox.Show("You must enter a Port and Nickname to host a server.", "Missing Info");
return;
}
startListening();
}
public void startListening()
{
try
{
this.isHost = true; //We're hosting this server
cw.callingForm = this; //Give ChatForm the login form (this) [that acts as the server]
cw.Show(); //Show ChatForm
cw.isHost = true; //Tell ChatForm it is the host (for display purposes)
this.Hide(); //And hide the login form
serverSocket.Bind(new IPEndPoint(IPAddress.Any, int.Parse(portBox.Text))); //Bind to our local address
serverSocket.Listen(1); //And start listening
serverSocket.BeginAccept(new AsyncCallback(AcceptCallback), null); //When someone connects, begin the async callback
cw.connectTo("127.0.0.1", int.Parse(portBox.Text), nicknameBox.Text); //And have ChatForm connect to the server
}
catch (Exception) {}
}
public void AcceptCallback(IAsyncResult AR)
{
try
{
StateObject state = new StateObject();
state.workSocket = serverSocket.EndAccept(AR);
socketList.Add(state.workSocket);
state.workSocket.BeginReceive(state.buffer, 0, StateObject.BufferSize, SocketFlags.None, new AsyncCallback(ReceiveCallback), state);
serverSocket.BeginAccept(new AsyncCallback(AcceptCallback), null);
}
catch (Exception) {}
}
public void ReceiveCallback(IAsyncResult AR)
{
try
{
if (isClosing)
return;
StateObject state = (StateObject)AR.AsyncState;
Socket s = state.workSocket;
String content = "";
int received = s.EndReceive(AR);
if(received > 0)
state.sb.Append(Encoding.ASCII.GetString(state.buffer, 0, received));
content = state.sb.ToString();
if (content.IndexOf(Environment.NewLine) > -1) //If we've received the end of the message
{
if (content.StartsWith("!!addlist") && state.newConnection)
{
state.newConnection = false;
content = content.Replace("!!addlist", "");
string userNick = content.Trim();
if (isHost && userNick.StartsWith("!"))
userNick = userNick.Replace("!", "");
userNick = userNick.Trim();
if (userNick.StartsWith("!") || userNick == string.Empty || usernames.Items.IndexOf(userNick) > -1)
{
//Invalid Username :c get dropped
s.Send(Encoding.ASCII.GetBytes("Invalid Username/In Use - Sorry :("));
s.Shutdown(SocketShutdown.Both);
s.Disconnect(false);
s.Close();
socketList.Remove(s);
return;
}
usernames.Items.Add(userNick);
foreach (string name in usernames.Items)
{
if (name.IndexOf(userNick) < 0)
{
s.Send(Encoding.ASCII.GetBytes("!!addlist " + name + "\r\n"));
Thread.Sleep(10); //such a hack... ugh it annoys me that this works
}
}
foreach (Socket client in socketList)
{
try
{
if (client != s)
client.Send(Encoding.ASCII.GetBytes("!!addlist " + userNick + "\r\n"));
}
catch (Exception) { }
}
}
else if (content.StartsWith("!!removelist") && !state.newConnection)
{
content = content.Replace("!!removelist", "");
string userNick = content.Trim();
usernames.Items.Remove(userNick);
foreach (Socket client in socketList)
{
try
{
if (client != s)
client.Send(Encoding.ASCII.GetBytes("!!removelist " + userNick + "\r\n"));
}
catch (Exception) { }
}
}
else if (state.newConnection) //if they don't give their name and try to send data, just drop.
{
s.Shutdown(SocketShutdown.Both);
s.Disconnect(false);
s.Close();
socketList.Remove(s);
return;
}
else
{
foreach (Socket client in socketList)
{
try
{
if (client != s)
client.Send(System.Text.Encoding.ASCII.GetBytes(content));
}
catch (Exception) { }
}
}
}
Array.Clear(state.buffer, 0, StateObject.BufferSize);
state.sb.Clear();
s.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0, new AsyncCallback(ReceiveCallback), state);
}
catch (Exception) {
socketList.Remove(((StateObject)AR.AsyncState).workSocket);
}
}
public void SendCallback(IAsyncResult AR)
{
try
{
StateObject state = (StateObject)AR.AsyncState;
state.workSocket.EndSend(AR);
}
catch (Exception) {}
}
private void Login_FormClosed(object sender, FormClosedEventArgs e)
{
try
{
this.isClosing = true;
if (this.isHost)
{
foreach (Socket c in socketList)
{
if (c.Connected)
{
c.Close();
}
}
serverSocket.Shutdown(SocketShutdown.Both);
serverSocket.Close();
serverSocket = null;
serverSocket.Dispose();
}
socketList.Clear();
}
catch (Exception) { }
finally
{
Application.Exit();
}
}
}
public class StateObject
{
public Socket workSocket = null;
public const int BufferSize = 1024;
public byte[] buffer = new byte[BufferSize];
public StringBuilder sb = new StringBuilder();
public bool newConnection = true;
}
The client code (work in progress):
public partial class ChatWindow : Form
{
private Socket clientSocket;
private Thread chatThread;
private string ipAddress;
private int port;
private bool isConnected;
private string nickName;
public bool isHost;
public Login callingForm;
private static object conLock = new object();
public ChatWindow()
{
InitializeComponent();
isConnected = false;
isHost = false;
}
public string getIP() {
return Dns.GetHostEntry(Dns.GetHostName()).AddressList.FirstOrDefault(ip => ip.AddressFamily == AddressFamily.InterNetwork).ToString();
}
public void displayError(string err)
{
output(Environment.NewLine + Environment.NewLine + err + Environment.NewLine);
}
public void op(string s)
{
try
{
lock (conLock)
{
chatBox.Text += s;
}
}
catch (Exception) { }
}
public void connectTo(string ip, int p, string n) {
try
{
this.Text = "Trying to connect to " + ip + ":" + p + "...";
this.ipAddress = ip;
this.port = p;
this.nickName = n;
clientSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
if (!isHost)
{
op("Connecting to " + ipAddress + ":" + port + "...");
}
else
{
output("Listening on " + getIP() + ":" + port + "...");
}
clientSocket.Connect(ipAddress, port);
isConnected = true;
if (!isHost)
{
this.Text = "Connected to " + ipAddress + ":" + port + " - Nickname: " + nickName;
output("Connected!");
}
else
{
this.Text = "Hosting on " + getIP() + ":" + port + " - Nickname: " + nickName;
}
chatThread = new Thread(new ThreadStart(getData));
chatThread.Start();
nickName = nickName.Replace(" ", "");
nickName = nickName.Replace(":", "");
if(nickName.StartsWith("!"))
nickName = nickName.Replace("!", "");
namesBox.Items.Add(nickName);
sendRaw("!!addlist " + nickName);
}
catch (ThreadAbortException)
{
//do nothing; probably closing chat window
}
catch (Exception e)
{
if (!isConnected)
{
this.Hide();
callingForm.Show();
clearText();
MessageBox.Show("Error:\n\n" + e.ToString(), "Error connecting to remote host");
}
}
}
public void removeNick(string n)
{
if (namesBox.Items.Count <= 0)
return;
for (int x = namesBox.Items.Count - 1; x >= 0; --x)
if (namesBox.Items[x].ToString().Contains(n))
namesBox.Items.RemoveAt(x);
}
public void clearText()
{
try
{
lock (conLock)
{
chatBox.Text = "";
}
}
catch (Exception) { }
}
public void addNick(string n)
{
if (n.Contains(" ")) //No Spaces... such a headache
return;
if (n.Contains(":"))
return;
bool shouldAdd = true;
n = n.Trim();
for (int x = namesBox.Items.Count - 1; x >= 0; --x)
if (namesBox.Items[x].ToString().Contains(n))
shouldAdd = false;
if (shouldAdd)
{
namesBox.Items.Add(n);
output("Someone new joined the room: " + n);
//sendRaw("!!addlist " + nickName);
}
}
public void addNickNoMessage(string n)
{
if (n.Contains(" ")) //No Spaces... such a headache
return;
if (n.Contains(":"))
return;
bool shouldAdd = true;
n = n.Trim();
for (int x = namesBox.Items.Count - 1; x >= 0; --x)
if (namesBox.Items[x].ToString().Contains(n))
shouldAdd = false;
if (shouldAdd)
{
namesBox.Items.Add(n);
//sendRaw("!!addlist " + nickName);
}
}
public void getData()
{
try
{
byte[] buf = new byte[1024];
string message = "";
while(isConnected)
{
Array.Clear(buf, 0, buf.Length);
message = "";
int gotData = clientSocket.Receive(buf, buf.Length, SocketFlags.None);
if (gotData == 0)
throw new Exception("I swear, this was working before but isn't anymore...");
message = Encoding.ASCII.GetString(buf);
if (message.StartsWith("!!addlist"))
{
message = message.Replace("!!addlist", "");
string userNick = message.Trim();
if(!namesBox.Items.Contains(userNick))
{
addNick(userNick);
}
continue;
}
else if (message.StartsWith("!!removelist"))
{
message = message.Replace("!!removelist", "");
string userNick = message.Trim();
removeNick(userNick);
output("Someone left the room: " + userNick);
continue;
}
output(message);
}
}
catch (Exception)
{
isConnected = false;
output(Environment.NewLine + "Connection to the server lost.");
}
}
public void output(string s)
{
try
{
lock (conLock)
{
chatBox.Text += s + Environment.NewLine;
}
}
catch (Exception) { }
}
private void ChatWindow_FormClosed(object sender, FormClosedEventArgs e)
{
try
{
if(isConnected)
sendRaw("!!removelist " + nickName);
isConnected = false;
clientSocket.Shutdown(SocketShutdown.Receive);
if (chatThread.IsAlive)
chatThread.Abort();
callingForm.Close();
}
catch (Exception) { }
}
private void sendButton_Click(object sender, EventArgs e)
{
if(isConnected)
send(sendBox.Text);
}
private void sendBox_KeyUp(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Enter)
{
if (isConnected)
{
if (sendBox.Text != "")
{
send(sendBox.Text);
sendBox.SelectAll();
e.SuppressKeyPress = true;
e.Handled = true;
}
}
}
}
private void send(string t) {
try
{
byte[] data = System.Text.Encoding.ASCII.GetBytes(nickName + ": " + t + "\r\n");
clientSocket.Send(data);
output(nickName + ": " + t);
}
catch (Exception e)
{
displayError(e.ToString());
}
}
private void sendRaw(string t)
{
try
{
byte[] data = System.Text.Encoding.ASCII.GetBytes(t + "\r\n");
clientSocket.Send(data);
}
catch (Exception e)
{
displayError(e.ToString());
}
}
private void chatBox_TextChanged(object sender, EventArgs e)
{
chatBox.SelectionStart = chatBox.Text.Length;
chatBox.ScrollToCaret();
}
private void sendBox_KeyDown(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Enter)
e.SuppressKeyPress = true;
}
}
To do:
Add invokes, more delegates, do some more QA and find out what breaks it.
Also, I believe there's still the possibility of packet loss due to the client addlist functions being in the read loop. I believe this is why the "crappy hack" using Thread.Sleep(10) in the server callback for name population is an issue.
I think it might be better to either pass the command off to another thread while continuing to read or have the client tell the server it's ready for another name.
Otherwise, there might be some data loss during name updates.
The other thing is that, as was said in the comments above, delegates should be used when updating the UI objects (chatbox and listbox). I wrote the code for these but ultimately removed it because there was no noticeable change and I wanted to keep it simple.
I do still use an object lock when outputting text to the chatbox, but there's no noticeable difference there.
The code should be added as not using delegates is potentially problematic, but I literally caught the chat box in an infinite loop of updates without issue.
I tried breaking it with telnet and was successful so I added a newConnection property to the StateObject to ensure that each client can only send "!!addlist" once.
There are, of course, other ways to abuse the server by creating a client that joins and leaves repeatedly, so ultimately I will probably end up passing the !!removelist handling to the server instead of leaving it up to the client.