hey all,
I have made a socket server in C# for a flash game that I am developing, I got the code from somewhere and I am a beginner in c# and .net development . It works fine in practice when connections are made and the server functions correctly. Get 2 concurrent connections at the same time and we have a problem.
here is the basic aspects of the socket server below: (alot taken out for obvious reasons)
how can I alter this so that it can handle concurrent connections? Should I be threading each response?
Thanks
class TcpSock
{
int tcpIndx = 0;
int tcpByte = 0;
byte[] tcpRecv = new byte[1024];
////////////////////////////////////////
public Socket tcpSock;
////////////////////////////////////////
public int Recv(ref string tcpRead)
{
tcpByte = tcpSock.Available;
if (tcpByte > tcpRecv.Length - tcpIndx)
tcpByte = tcpRecv.Length - tcpIndx;
tcpByte = tcpSock.Receive(tcpRecv, tcpIndx, tcpByte,
SocketFlags.Partial);
tcpRead = Encoding.ASCII.GetString
(tcpRecv, tcpIndx, tcpByte);
tcpIndx += tcpByte;
return tcpRead.Length;
}
public int RecvLn(ref string tcpRead)
{
tcpRead = Encoding.ASCII.GetString
(tcpRecv, 0, tcpIndx);
tcpIndx = 0;
return tcpRead.Length;
}
public int Send(string tcpWrite)
{
return tcpSock.Send(Encoding.ASCII.GetBytes(tcpWrite));
}
public int SendLn(string tcpWrite)
{
return tcpSock.Send(Encoding.ASCII.GetBytes(tcpWrite + "\r\n"));
}
}
[STAThread]
static void Main()
{
Thread Server1 = new Thread(RunServer);
Server1.Start();
}
static void RunServer()
{
///class IPHostEntry : Stores information about the Host and is required
///for IPEndPoint.
///class IPEndPoint : Stores information about the Host IP Address and
///the Port number.
///class TcpSock : Invokes the constructor and creates an instance.
///class ArrayList : Stores a dynamic array of Client TcpSock objects.
IPHostEntry Iphe = Dns.Resolve(Dns.GetHostName());
IPEndPoint Ipep = new IPEndPoint(Iphe.AddressList[0], 4444);
Socket Server = new Socket(Ipep.Address.AddressFamily,SocketType.Stream, ProtocolType.Tcp);
///Initialize
///Capacity : Maximux number of clients able to connect.
///Blocking : Determines if the Server TcpSock will stop code execution
///to receive data from the Client TcpSock.
///Bind : Binds the Server TcpSock to the Host IP Address and the Port Number.
///Listen : Begin listening to the Port; it is now ready to accept connections.
ArrayList Client = new ArrayList();
string[,] Users = new string[1000,9];
string rln = null;
string[] Data;
Client.Capacity = 1000;
Server.Blocking = false;
Server.Bind(Ipep);
Server.Listen(32);
Console.WriteLine("Server 1 {0}: listening to port {1}", Dns.GetHostName(), Ipep.Port);
////////////////////////////////////////////////////////////////////////////////////////////
///Main loop
///1. Poll the Server TcpSock; if true then accept the new connection.
///2. Poll the Client TcpSock; if true then receive data from Clients.
while (true)
{
//Accept - new connection
#region new connection
if (Server.Poll(0, SelectMode.SelectRead))
{
int i = Client.Add(new TcpSock());
((TcpSock)Client[i]).tcpSock = Server.Accept();
Console.WriteLine("Client " + i + " connected.");
Users[i, 0] = i.ToString();
}
#endregion
for (int i = 0; i < Client.Count; i++)
{
//check for incoming data
if (((TcpSock)Client[i]).tcpSock.Poll(0, SelectMode.SelectRead))
{
//receive incoming data
if (((TcpSock)Client[i]).Recv(ref rln) > 0)
{
Console.WriteLine(rln.ToString());
Data = rln.Split('|');
// 1) initial connection
#region InitialConnection
if (Data[0] == "0000")
{
}
}
}
}
}
}
You will need to not use synchronous functions but asynchrounus functions like Socket.BeginReceive
using System;
using System.IO;
using System.Net;
using System.Net.Sockets;
using System.Text;
public static partial class TcpServer
{
public static void Main()
{
// Setup listener on "localhost" port 12000
IPAddress ipAddr = Dns.GetHostEntry("localhost").AddressList[0];
TcpListener server = new TcpListener(ipAddr, 12000);
server.Start(); // Network driver can now allow incoming requests
// Accept up to 1 client per CPU simultaneously
Int32 numConcurrentClients = Environment.ProcessorCount;
for (Int32 n = 0; n
private static Byte[] ProcessData(Byte[] inputData)
{
String inputString = Encoding.UTF8.GetString(inputData, 1, inputData[0]);
String outputString = inputString.ToUpperInvariant();
Console.WriteLine("Input={0}", inputString);
Console.WriteLine(" Output={0}", outputString);
Console.WriteLine();
Byte[] outputStringBytes = Encoding.UTF8.GetBytes(outputString);
Byte[] outputData = new Byte[1 + outputStringBytes.Length];
outputData[0] = (Byte)outputStringBytes.Length;
Array.Copy(outputStringBytes, 0, outputData, 1, outputStringBytes.Length);
return outputData;
}
}
public static partial class TcpServer
{
private sealed class ClientConnectionApm
{
private TcpListener m_server;
private TcpClient m_client;
private Stream m_stream;
private Byte[] m_inputData = new Byte[1];
private Byte m_bytesReadSoFar = 0;
public ClientConnectionApm(TcpListener server)
{
m_server = server;
m_server.BeginAcceptTcpClient(AcceptCompleted, null);
}
private void AcceptCompleted(IAsyncResult ar)
{
// Connect to this client
m_client = m_server.EndAcceptTcpClient(ar);
// Accept another client
new ClientConnectionApm(m_server);
// Start processing this client
m_stream = m_client.GetStream();
// Read 1 byte from client which contains length of additional data
m_stream.BeginRead(m_inputData, 0, 1, ReadLengthCompleted, null);
}
private void ReadLengthCompleted(IAsyncResult result)
{
// If client closed connection; abandon this client request
if (m_stream.EndRead(result) == 0) { m_client.Close(); return; }
// Start to read 'length' bytes of data from client
Int32 dataLength = m_inputData[0];
Array.Resize(ref m_inputData, 1 + dataLength);
m_stream.BeginRead(m_inputData, 1, dataLength, ReadDataCompleted, null);
}
private void ReadDataCompleted(IAsyncResult ar)
{
// Get number of bytes read from client
Int32 numBytesReadThisTime = m_stream.EndRead(ar);
// If client closed connection; abandon this client request
if (numBytesReadThisTime == 0) { m_client.Close(); return; }
// Continue to read bytes from client until all bytes are in
m_bytesReadSoFar += (Byte)numBytesReadThisTime;
if (m_bytesReadSoFar
private void WriteDataCompleted(IAsyncResult ar)
{
// After result is written to client, close the connection
m_stream.EndWrite(ar);
m_client.Close();
}
}
}
First of all: Stop using non-blocking sockets. In .NET you should either stick to the synchronous methods Receive/Send or asynchronous methods BeginReceive/BeginSend.
You should only stick with sync methods if you will have only a handful of clients. Then launch each new client in a new thread. This is the easiest option to get everthing running.
Simply do like this:
public void AcceptClients()
{
TcpListener listener = new TcpListener(IPAddress.Any, 5566);
listener.Start();
while (_serverRunning)
{
var socket = listener.AcceptSocket();
new Thread(ClientFunc).Start(socket);
}
}
public void ClientFun(object state)
{
var clientSocket = (Socket)state;
var buffer = new byte[65535];
while (_serverRunning)
{
//blocking read.
clientSocket.Receive(buffer, 0, buffer.Length, SocketFlags.None);
//check packet.
// handle packet
// send respons.
clientSocket.Send(alalalal);
}
}
You should refactor the methods so that they follow SRP. The code is just a small guide to get you going.
Related
I'm building a simple server, that contains some information and that will be using Async Sockets to get N Connections (I don't really know how many, they can range from 50 to 1000).
The main purpose of this server is to 'verify' the file integrity and version of clients connecting, and if needed send them the updated files so they can patch.
Right now, I'm on the part of getting my sockets running, I can display the data in the console, and everything is fine, problem is, my most important variables are on my 'DownloadServer' class, while my socket functions are on a class named 'ServerSocket'.
My question is, how can I access the data in DownloadServer(that contains an instance of ServerSocket) when said info is requested to my socket. I can't return the data received with Async Callbacks (because they must be void), so what would be the best way to go about this?
Here's my socket code, it only receives a client and prints data sent. What I want to do is acess the received info (likewise, a command for example) and return to the client the request info, for example, if the message received is "GetFileVersion", the server should reply back with the value of the variable it contains (it's a global variable named FILEVERSION), being the problem that I can't seem to find a way to acces that variable.
class ServerSocket
{
private Socket _socket;
private byte[] _buffer;
public ServerSocket()
{
_socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
}
public void bind(int port)
{
_socket.Bind(new IPEndPoint(IPAddress.Any, port));
}
public void Listen(int backlog)
{
_socket.Listen(backlog);
}
public void Accept()
{
_socket.BeginAccept(AcceptCallBack, null);
}
private void AcceptCallBack(IAsyncResult ar)
{
Socket clientSocket = _socket.EndAccept(ar);
Accept();
IPEndPoint clientEndPoint = (IPEndPoint)clientSocket.RemoteEndPoint;
Console.WriteLine("Client Connected: {0}",clientEndPoint.Address.ToString());
_buffer = new byte[2048];
clientSocket.BeginReceive(_buffer, 0, _buffer.Length, SocketFlags.None, ReceivedCallback, clientSocket);
}
private void ReceivedCallback(IAsyncResult ar)
{
try
{
Socket clientSocket = ar.AsyncState as Socket;
int size = clientSocket.EndReceive(ar);
byte[] packet = new byte[size];
Array.Copy(_buffer, packet, packet.Length);
String data = System.Text.Encoding.ASCII.GetString(packet, 0, packet.Length);
}
catch (Exception ex)
{
;
}
}
}
}
Thank you in advance!
EDIT:
What I'd like to do is something like String commandReceived = socket.Receive() (like you would do with synchronous sockets), or some way to acess that command received via that socket.
class DownloadServer
{
private static String UPDATEPATH="";
private static int FILEVERSION;
private static string ROOTPATH = "";
private String SQLUsername = "";
private String SQLPassword = "";
private String AccountDB = "";
private String ServerName = "";
private SqlConnection sqlConn;
//some logic methods
static void Main(string[] args){
ServerSecurity serverSecurity = new ServerSecurity();
ServerSocket serverSocket = new ServerSocket();
serv.Initialize();
serverSecurity.Initialize();
serverSocket.bind(15779);
serverSocket.Listen(1000);
serverSocket.Accept();
while (true)
{
Console.WriteLine("Input the command:");
var Input = Console.ReadLine();
if (Input == "Update")
{
serv.prepareUpdate();
}
else if (Input == "Exit")
{
Environment.Exit(0);
}
else if (Input == "TestEncryption")
{
Console.WriteLine("Enter the text to be encrypted:");
String plainText = Console.ReadLine();
Console.WriteLine("Original Text = {0}", plainText);
Console.WriteLine("Encrypted Text = {0}", serverSecurity.Encrypt(plainText));
Console.WriteLine("Decrypted Text = {0}", serverSecurity.Decrypt(serverSecurity.Encrypt(plainText)));
}
}
}
Add in your DownloadServer Class :
Socket NewSocket;
byte[] buffer = new buffer [1024];
NewSocket = serverSocket.Accept();
Then begin Receive from this NewSocket :
void Receive()
{
NewSocket.BeginReceive(buffer, 0, buffer.Length, SocketFlags.None, ReceiveCallback, r);
}
private void ReceiveCallback(IAsyncResult ar)
{
Socket CurrentClient = (Socket)ar.AsyncState;
int Received;
try { Received = CurrentClient.Receive(buffer); }
catch
{
return;
}
byte[] _buffer = new byte[Received];
Array.Copy(buffer, _buffer, Received);
string _Text = Encoding.Unicode.GetString(_buffer);
if(_Text == "GetVersion")
byte[] infoVersion = Encoding.Encoding.Default.GetBytes(FILEVERSION);
CurrentClient .Send(infoVersion )
}
This looks like a classic design problem where you are attempting to give a class too many responsibilities. In SOLID design, each class should have a single responsibility. The SocketServer would then only be responsible for creating the socket and sending/receiving data. Your DownloadServer would be responsible for creating data to be sent. Another class say ValidationServer, would be responsible for requesting data through the SocketServer and parsing it. A third class, a controller if you will, would be responsible for coordinating calls and passing data between these classes. In this way your SocketServer and DownloadServer would be decoupled and not require variables from each other.
In a project I have multiple senders of UDP data, but only a single receiver.
If traffic gets higher, the receiver "forgets" lots of packets. I know that this is a problem inherent to UDP, but I want to minimize the number of lost packets.
I have read this SO question before!
Here is my code (Please excuse the massive code blocks, but I wanted the example to be self contained)
Sender side:
public class UdpSender
{
private static int portNumber = 15000;
public void Send(string data)
{
var udpServer = new UdpClient();
var ipEndPoint = new IPEndPoint(IPAddress.Broadcast, portNumber);
byte[] bytes = Encoding.ASCII.GetBytes(data);
udpServer.Send(bytes, bytes.Length, ipEndPoint);
udpServer.Close();
}
}
class Program
{
static void Main(string[] args)
{
var sender = new UdpSender();
var count = 100000;
for (var i = 0; i < count; ++i)
{
sender.Send(i.ToString());
}
Console.ReadKey();
}
}
Receiver side:
public class UDPListener
{
private static int portNumber = 15000;
private readonly UdpClient udp = new UdpClient(portNumber);
public volatile int CountOfReceived = 0;
public void StartListening()
{
this.udp.BeginReceive(Receive, new object());
}
private void Receive(IAsyncResult ar)
{
Interlocked.Increment(ref CountOfReceived);
IPEndPoint ip = new IPEndPoint(IPAddress.Any, portNumber);
byte[] bytes = udp.EndReceive(ar, ref ip);
string message = Encoding.ASCII.GetString(bytes);
StartListening();
}
}
class Program
{
static void Main(string[] args)
{
var listener = new UDPListener();
listener.StartListening();
while (true)
{
Console.WriteLine(listener.CountOfReceived.ToString("000,000,000"));
}
}
}
Right now if I start 5 sender applications in parallel, only about a quarter of the messages is received. This is only on my local machine.
What can I do to minimize packets lost?
thinking about the speed you're sending your packets on their trip i would say that the sinks buffer might be filled in a bit of time - increasing the buffer size (as shown here) could solve this issue, i guess.
My first question here. I am new to this kind of programming, and i've only programmed .NET web sites and forms.
Now, the company I work at, asks me to make an ActiveX component, that listens to UDP messages, and turns them into events.
The UDP msgs are send from Avaya system, so i was told that to test my ActiveX, at first I need to create an app, that only sends UDP (only one button that sends pre-defined UDP string). And then create listener socket, ordinary C# app, that will get those transmitted UDP string from the tests app. Both apps will work on the same machine.
Later, when i get this working, i need to make the listener an ActiveX component, but first things first.
I need to know if there are any good tutorials about this, and any idea on how to start? I am sorry for my ignorance, but i am really new on this and i don't really have any time to learn this since it has to be done in 2 weeks.
Thanks in advance.
edit: I managed to create 2 simple console applications, and was sending UDP messages between them successfully. The sender will be only for testing, and now I need to re-make my receiver to get the UDP message and 'translate' it to events. And lastly, to make it an ActiveX control...
Simple server and client:
public struct Received
{
public IPEndPoint Sender;
public string Message;
}
abstract class UdpBase
{
protected UdpClient Client;
protected UdpBase()
{
Client = new UdpClient();
}
public async Task<Received> Receive()
{
var result = await Client.ReceiveAsync();
return new Received()
{
Message = Encoding.ASCII.GetString(result.Buffer, 0, result.Buffer.Length),
Sender = result.RemoteEndPoint
};
}
}
//Server
class UdpListener : UdpBase
{
private IPEndPoint _listenOn;
public UdpListener() : this(new IPEndPoint(IPAddress.Any,32123))
{
}
public UdpListener(IPEndPoint endpoint)
{
_listenOn = endpoint;
Client = new UdpClient(_listenOn);
}
public void Reply(string message,IPEndPoint endpoint)
{
var datagram = Encoding.ASCII.GetBytes(message);
Client.Send(datagram, datagram.Length,endpoint);
}
}
//Client
class UdpUser : UdpBase
{
private UdpUser(){}
public static UdpUser ConnectTo(string hostname, int port)
{
var connection = new UdpUser();
connection.Client.Connect(hostname, port);
return connection;
}
public void Send(string message)
{
var datagram = Encoding.ASCII.GetBytes(message);
Client.Send(datagram, datagram.Length);
}
}
class Program
{
static void Main(string[] args)
{
//create a new server
var server = new UdpListener();
//start listening for messages and copy the messages back to the client
Task.Factory.StartNew(async () => {
while (true)
{
var received = await server.Receive();
server.Reply("copy " + received.Message, received.Sender);
if (received.Message == "quit")
break;
}
});
//create a new client
var client = UdpUser.ConnectTo("127.0.0.1", 32123);
//wait for reply messages from server and send them to console
Task.Factory.StartNew(async () => {
while (true)
{
try
{
var received = await client.Receive();
Console.WriteLine(received.Message);
if (received.Message.Contains("quit"))
break;
}
catch (Exception ex)
{
Debug.Write(ex);
}
}
});
//type ahead :-)
string read;
do
{
read = Console.ReadLine();
client.Send(read);
} while (read != "quit");
}
}
Simple server and client:
using System;
using System.Text;
using System.Net;
using System.Net.Sockets;
class Program
{
static void Main(string[] args)
{
// Create UDP client
int receiverPort = 20000;
UdpClient receiver = new UdpClient(receiverPort);
// Display some information
Console.WriteLine("Starting Upd receiving on port: " + receiverPort);
Console.WriteLine("Press any key to quit.");
Console.WriteLine("-------------------------------\n");
// Start async receiving
receiver.BeginReceive(DataReceived, receiver);
// Send some test messages
using (UdpClient sender1 = new UdpClient(19999))
sender1.Send(Encoding.ASCII.GetBytes("Hi!"), 3, "localhost", receiverPort);
using (UdpClient sender2 = new UdpClient(20001))
sender2.Send(Encoding.ASCII.GetBytes("Hi!"), 3, "localhost", receiverPort);
// Wait for any key to terminate application
Console.ReadKey();
}
private static void DataReceived(IAsyncResult ar)
{
UdpClient c = (UdpClient)ar.AsyncState;
IPEndPoint receivedIpEndPoint = new IPEndPoint(IPAddress.Any, 0);
Byte[] receivedBytes = c.EndReceive(ar, ref receivedIpEndPoint);
// Convert data to ASCII and print in console
string receivedText = ASCIIEncoding.ASCII.GetString(receivedBytes);
Console.Write(receivedIpEndPoint + ": " + receivedText + Environment.NewLine);
// Restart listening for udp data packages
c.BeginReceive(DataReceived, ar.AsyncState);
}
}
Server
public void serverThread()
{
UdpClient udpClient = new UdpClient(8080);
while(true)
{
IPEndPoint RemoteIpEndPoint = new IPEndPoint(IPAddress.Any, 0);
Byte[] receiveBytes = udpClient.Receive(ref RemoteIpEndPoint);
string returnData = Encoding.ASCII.GetString(receiveBytes);
lbConnections.Items.Add(RemoteIpEndPoint.Address.ToString()
+ ":" + returnData.ToString());
}
}
And initialize the thread
private void Form1_Load(object sender, System.EventArgs e)
{
Thread thdUDPServer = new Thread(new ThreadStart(serverThread));
thdUDPServer.Start();
}
Client
private void button1_Click(object sender, System.EventArgs e)
{
UdpClient udpClient = new UdpClient();
udpClient.Connect(txtbHost.Text, 8080);
Byte[] senddata = Encoding.ASCII.GetBytes("Hello World");
udpClient.Send(senddata, senddata.Length);
}
Insert it to button command.
Source: http://technotif.com/creating-simple-udp-server-client-transfer-data-using-c-vb-net/
I am in desperate need of help. I have essentially created a program that (will use) encryption to send messages back and forth. The encryption part is working fine, however I am fairly new to Threads and I can not for the life of me get my Client/Server pieces of the application to line up. The chat program is direct IP connection using TCP, so each host is a client and a server. The issue I appear to be having, when I debug, is that the server thread is either not ready when the Client tries to connect to it, or if it is ready it will not relinquish the Thread so the Client can connect! I have been working on this for hours and it is very frustrating.. I hope someone can help! I've included my code below.
This is my code snippet from my MainForm, which constructs the Client and Server aspects:
private void InitializeComponent() {
server = new ServerSide("127.0.0.1",7865);
servThread = new Thread(new ThreadStart(server.begin));
client = new ClientSide("127.0.0.1",7865);
clientThread = new Thread(new ThreadStart(client.begin));
servThread.Start();
clientThread.Start();
//servThread.Join();
//clientThread.Join();
}
This is my ServerSide code:
public class ServerSide
{
String IpString;
int tcpPort;
bool goodToGo = false;
System.Net.IPAddress ipAddress = null;
public ServerSide(String ip, int tcpPort)
{
IpString = ip;
bool isValidIp = System.Net.IPAddress.TryParse(IpString, out ipAddress);
if (isValidIp == true) // check if the IP is valid, set the bool to true if so
{
goodToGo = true;
}
else
{
goodToGo = false;
}
}
public void begin()
{
try
{
IPAddress ipAd = IPAddress.Parse(IpString);
/* Initializes the Listener */
TcpListener myList = new TcpListener(ipAd, tcpPort);
Socket s = null;
/* Start Listening at the specified port */
while (true)
{
myList.Start();
if (myList.Pending())
{
s = myList.AcceptSocket();
break;
}
}
String toReceive = "";
while (true)
{
byte[] b = new byte[4096];
int k = s.Receive(b);
for (int i = 0; i < k; i++)
toReceive += Convert.ToString((Convert.ToChar(b[i])));
// ASCIIEncoding asen = new ASCIIEncoding();
var form = MainForm.ActiveForm as MainForm;
if (form != null)
{
form.messageReceived(toReceive);
}
toReceive = "";
}
}
catch (Exception e)
{
Console.WriteLine("Error..... " + e.StackTrace);
}
}
}
}
ClientSide code:
public class ClientSide
{
private String IpString;
private int tcpPort;
private TcpClient tcpInt;
private static Stream stm;
private System.Net.IPAddress ipAddress = null;
private bool goodToGo = false;
public ClientSide(String ip, int tcpPort)
{
IpString = ip;
this.tcpPort = tcpPort;
bool isValidIp = System.Net.IPAddress.TryParse(IpString, out ipAddress);
if (isValidIp == true)
{
goodToGo = true;
}
else
{
goodToGo = false;
}
}
public void begin()
{
try
{
tcpInt = new TcpClient();
// Console.WriteLine("Connecting.....");
tcpInt.Connect(IpString, tcpPort);
// use the ipaddress as in the server program
// Console.WriteLine("Connected");
// String str = Console.ReadLine();
stm = tcpInt.GetStream();
}
catch (Exception e)
{
Console.WriteLine("Error..... " + e.StackTrace);
}
}
public void sendMessage(String str)
{
// stm = tcpInt.GetStream();
ASCIIEncoding asen = new ASCIIEncoding();
byte[] ba = asen.GetBytes(str);
stm.Write(ba, 0, ba.Length);
/** byte[] bb = new byte[100];
int k = stm.Read(bb, 0, 100);
for (int i = 0; i < k; i++)
Console.Write(Convert.ToChar(bb[i]));*/
}
}
}
Once again.. what typically happens is my Client receives an error that the host actively refused the connection.. but I do not know how to time them. I am looking for how to have my server listening for TCP Connections, but still manage to go to my other thread to create the TCP Connecion to send the server (I am testing this on localhost currently).
Thanks.
In the constructor of the ServerSide class, you forgot to initialize the tcpPort member. Because you forgot, the server will try to listen to port 0 and the client will try to connect to port 7865, and it will fail.
Try adding this code to the constructor in the ServerSide class.
this.tcpPort = tcpPort;
As for the threads, you might have a problem if the client thread tries to connect before the server thread has started listening. You can use a loop to try to connect a number of times (let's say 10), with a timeout (let's say 1 second) if you don't succeed. This way, you will retry 10 times and give up after that.
I'm trying to write a service that listens to a TCP Socket on a given port until an end of line is recived and then based on the "line" that was received executes a command.
I've followed a basic socket programming tutorial for c# and have come up with the following code to listen to a socket:
public void StartListening()
{
_log.Debug("Creating Maing TCP Listen Socket");
_mainSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
IPEndPoint ipLocal = new IPEndPoint(IPAddress.Any, _port);
_log.Debug("Binding to local IP Address");
_mainSocket.Bind(ipLocal);
_log.DebugFormat("Listening to port {0}",_port);
_mainSocket.Listen(10);
_log.Debug("Creating Asynchronous callback for client connections");
_mainSocket.BeginAccept(new AsyncCallback(OnClientConnect), null);
}
public void OnClientConnect(IAsyncResult asyn)
{
try
{
_log.Debug("OnClientConnect Creating worker socket");
Socket workerSocket = _mainSocket.EndAccept(asyn);
_log.Debug("Adding worker socket to list");
_workerSockets.Add(workerSocket);
_log.Debug("Waiting For Data");
WaitForData(workerSocket);
_log.DebugFormat("Clients Connected [{0}]", _workerSockets.Count);
_mainSocket.BeginAccept(new AsyncCallback(OnClientConnect), null);
}
catch (ObjectDisposedException)
{
_log.Error("OnClientConnection: Socket has been closed\n");
}
catch (SocketException se)
{
_log.Error("Socket Exception", se);
}
}
public class SocketPacket
{
private System.Net.Sockets.Socket _currentSocket;
public System.Net.Sockets.Socket CurrentSocket
{
get { return _currentSocket; }
set { _currentSocket = value; }
}
private byte[] _dataBuffer = new byte[1];
public byte[] DataBuffer
{
get { return _dataBuffer; }
set { _dataBuffer = value; }
}
}
private void WaitForData(Socket workerSocket)
{
_log.Debug("Entering WaitForData");
try
{
lock (this)
{
if (_workerCallback == null)
{
_log.Debug("Initializing worker callback to OnDataRecieved");
_workerCallback = new AsyncCallback(OnDataRecieved);
}
}
SocketPacket socketPacket = new SocketPacket();
socketPacket.CurrentSocket = workerSocket;
workerSocket.BeginReceive(socketPacket.DataBuffer, 0, socketPacket.DataBuffer.Length, SocketFlags.None, _workerCallback, socketPacket);
}
catch (SocketException se)
{
_log.Error("Socket Exception", se);
}
}
public void OnDataRecieved(IAsyncResult asyn)
{
SocketPacket socketData = (SocketPacket)asyn.AsyncState;
try
{
int iRx = socketData.CurrentSocket.EndReceive(asyn);
char[] chars = new char[iRx + 1];
_log.DebugFormat("Created Char array to hold incomming data. [{0}]",iRx+1);
System.Text.Decoder decoder = System.Text.Encoding.UTF8.GetDecoder();
int charLength = decoder.GetChars(socketData.DataBuffer, 0, iRx, chars, 0);
_log.DebugFormat("Read [{0}] characters",charLength);
String data = new String(chars);
_log.DebugFormat("Read in String \"{0}\"",data);
WaitForData(socketData.CurrentSocket);
}
catch (ObjectDisposedException)
{
_log.Error("OnDataReceived: Socket has been closed. Removing Socket");
_workerSockets.Remove(socketData.CurrentSocket);
}
catch (SocketException se)
{
_log.Error("SocketException:",se);
_workerSockets.Remove(socketData.CurrentSocket);
}
}
This I thought was going to be a good basis for what I wanted to do, but the code I have appended the incoming characters to a text box one by one and didn't do anything with it. Which doesn't really work for what I want to do.
My main issue is the decoupling of the OnDataReceived method from the Wait for data method. which means I'm having issues building a string (I would use a string builder but I can accept multiple connections so that doesn't really work.
Ideally I'd like to look while listening to a socket until I see and end of line character and then call a method with the resulting string as a parameter.
What's the best way to go about doing this.
Try using asynch sockets. The code below will listening to a socket, and if the new line char through telnet is recieved it will echo it back out to the incomming socket. It seems like you would just need to redirect that input to your text box.
private string _hostName;
private const int _LISTENINGPORT = 23;
private Socket _incomingSocket;
byte[] _recievedData;
//todo: do we need 1024 byte? the asynch methods read the bytes as they come
//so when 1 byte typed == 1 byte read. Unless its new line then it is two.
private const int _DATASIZE = 1024;
public ConnectionServer()
{
IPAddress localAddr = IPAddress.Parse("127.0.0.1");
_hostName = Dns.GetHostName();
_recievedData = new byte[_DATASIZE];
_incomingSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
IPEndPoint endPoint = new IPEndPoint(localAddr, _LISTENINGPORT);
_incomingSocket.Bind(endPoint);
_incomingSocket.Listen(10);
}
~ConnectionServer()
{
}
public void StartListening()
{
_incomingSocket.BeginAccept(new AsyncCallback(OnAccept), _incomingSocket);
}
private void OnAccept(IAsyncResult result)
{
UserConnection connectionInfo = new UserConnection();
Socket acceptedSocket = (Socket)result.AsyncState;
connectionInfo.userSocket = acceptedSocket.EndAccept(result);
connectionInfo.messageBuffer = new byte[_DATASIZE];
//Begin acynch communication with target socket
connectionInfo.userSocket.BeginReceive(connectionInfo.messageBuffer, 0, _DATASIZE, SocketFlags.None,
new AsyncCallback(OnReceiveMessage), connectionInfo);
//reset the listnening socket to start accepting
_incomingSocket.BeginAccept(new AsyncCallback(OnAccept), result.AsyncState);
}
private void OnReceiveMessage(IAsyncResult result)
{
UserConnection connectionInfo = (UserConnection)result.AsyncState;
int bytesRead = connectionInfo.userSocket.EndReceive(result);
if (connectionInfo.messageBuffer[0] != 13 && connectionInfo.messageBuffer[1] != 10)
//ascii for newline and line feed
//todo dress this up
{
if (string.IsNullOrEmpty(connectionInfo.message))
{
connectionInfo.message = ASCIIEncoding.ASCII.GetString(connectionInfo.messageBuffer);
}
else
{
connectionInfo.message += ASCIIEncoding.ASCII.GetString(connectionInfo.messageBuffer);
}
}
else
{
connectionInfo.userSocket.Send(ASCIIEncoding.ASCII.GetBytes(connectionInfo.message), SocketFlags.None);
connectionInfo.userSocket.Send(connectionInfo.messageBuffer, SocketFlags.None);
connectionInfo.message = string.Empty;
connectionInfo.messageBuffer = new byte[_DATASIZE];
}
{
public class UserConnection
{
public Socket userSocket { get; set; }
public Byte[] messageBuffer { get; set; }
public string message { get; set; }
}
}
You seem to have several issues:
You have an asynchronous method called WaitForData. That's very confusing, as methods with the word Wait in their names generally block the currently executing thread until something happens (or, optionally, a timeout expires). This does the exact opposite. Are you intending for this to be a synchronous or asynchronous operation?
There's also no need to instantiate the Decoder object, nor do you need the char array for (it seems) anything; just call System.Text.Encoding.UTF8.GetString(socketData.DataBuffer, 0, iRx).
You also don't appear to be doing anything with lines...which is why it doesn't do anything with lines.
Your approach with using a StringBuilder is what I would do. I would add a StringBuilder to the SocketData class and call it Builder. As you capture string data, do something like this:
string[] data = System.Text.Encoding.UTF8.GetString(
socketData.DataBuffer, 0, iRx).Split(Environment.NewLine);
socketData.Builder.Append(data[0]);
for(int i = 1; i < data.Length; i++)
{
// the socketData.Builder variable now contains a single line, so do
// something with it here, like raise an event
OnLineReceived(builder.ToString());
socketData.Builder = new StringBuilder(data[i]);
}
The one caveat here is that UTF8 is a multi-byte encoding, meaning that you could potentially grab a chunk of data that cuts off mid-character. It's generally a better idea to do this sort of preprocessing on the other side of the communication, then send the data in an appropriately length-prefixed format.