Develop Reference

C# TCP connection lost

for the following code, my client makes a request to the server, but immediately as it does (after it connects successfully), I get this error "Network Error". I have been looking for extra info on it with the debugger but no luck. All of this is with the firewall down.
The connection lost event gives me the "Network error" generic message.
public class Server
{
private ServerConnectionContainer serverConnectionContainer;
public void StartServer()
{
Console.WriteLine("Please enter the server port and press return:");
string port = Console.ReadLine();
//1. Start listen on a port
serverConnectionContainer = ConnectionFactory.CreateServerConnectionContainer(int.Parse(port), false);
serverConnectionContainer.ConnectionLost += (a, b, c) =>
{
Console.WriteLine($"{serverConnectionContainer.Count} {b.ToString()} Connection lost {a.IPRemoteEndPoint.Port}. Reason {c.ToString()}");
};
serverConnectionContainer.ConnectionEstablished += connectionEstablished;
serverConnectionContainer.AllowUDPConnections = true;
serverConnectionContainer.Start();
Console.WriteLine("Server started");
while (true) {
}
}
/// <summary>
/// We got a connection.
/// </summary>
/// <param name="connection">The connection we got. (TCP or UDP)</param>
private void connectionEstablished(Connection connection, ConnectionType type)
{
connection.EnableLogging = true;
connection.LogIntoStream(Console.OpenStandardOutput());
Console.WriteLine($"{serverConnectionContainer.Count} {connection.GetType()} connected on port {connection.IPRemoteEndPoint.Port}");
//3. Register packet listeners.
connection.RegisterPacketHandler<TrainerRequest>(TrainerRequestReceived, this);
}
private void TrainerRequestReceived(TrainerRequest req, Connection connection)
{
Console.WriteLine($"RawDataPacket received. Data: {string.Join(", ", req.Data["pos_ally"])}");
var test = new Dictionary<string, byte[]>();
test.Add("pos_ally", new byte[] { 1, 2, 3, 4 });
connection.Send(new TrainerResponse(test, req));
}
}
public class Client
{
public static async Task StartClient()
{
//Request server IP and port number
Console.WriteLine("Please enter the server IP in the format 192.168.0.1 and press return:");
string ip = Console.ReadLine();
Console.WriteLine("Please enter the server port and press return:");
string port = Console.ReadLine();
//Parse the necessary information out of the provided string
ConnectionResult connectionResult = ConnectionResult.TCPConnectionNotAlive;
//1. Establish a connection to the server.
TcpConnection tcpConnection = ConnectionFactory.CreateTcpConnection(ip, int.Parse(port), out connectionResult);
//2. Register what happens if we get a connection
if (connectionResult == ConnectionResult.Connected)
{
Console.WriteLine($"{tcpConnection.ToString()} Connection established");
//3. Send a raw data packet request.
tcpConnection.KeepAlive = true;
while (true)
{
var test = new Dictionary<string, byte[]>();
test.Add("pos_ally", new byte[] { 5, 6, 7, 8 });
var res = await tcpConnection.SendAsync<TrainerResponse>(new TrainerRequest { Data = test });
Thread.Sleep(100);
}
}
}
}

While true was blocking my thread

How to create TCP message framing for the stream

Here is how my Client connects to the server:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
using System.Net.Sockets;
using System.IO;
using System;
using System.Text.RegularExpressions;
using UnityEngine.SceneManagement;
using Newtonsoft.Json;
using System.Linq;
public class ClientWorldServer : MonoBehaviour {
public bool socketReady;
public static TcpClient socket;
public static NetworkStream stream;
public static StreamWriter writer;
public static StreamReader reader;
public void ConnectToWorldServer()
{
if (socketReady)
{
return;
}
//Default host and port values;
string host = "127.0.0.1";
int port = 8080;
try
{
socket = new TcpClient(host, port);
stream = socket.GetStream();
writer = new StreamWriter(stream);
reader = new StreamReader(stream);
socketReady = true;
}
catch (Exception e)
{
Debug.Log("Socket error : " + e.Message);
}
}
}
Here is how i send data to the server using my Send function:
public void Send(string header, Dictionary<string, string> data)
{
if (stream.CanRead)
{
socketReady = true;
}
if (!socketReady)
{
return;
}
JsonData SendData = new JsonData();
SendData.header = "1x" + header;
foreach (var item in data)
{
SendData.data.Add(item.Key.ToString(), item.Value.ToString());
}
SendData.connectionId = connectionId;
string json = JsonConvert.SerializeObject(SendData);
var howManyBytes = json.Length * sizeof(Char);
writer.WriteLine(json);
writer.Flush();
Debug.Log("Client World:" + json);
}
As you can see i'm sending the data to the Stream like a string not like a byte array. As far as i know i should send the data as byte array prepending the size of the message and following the message. On the server side i have no clue how i can read that data.
Here is how i read it now(it works for now, but it will not work if i try to send more messages at once):
class WorldServer
{
public List<ServerClient> clients = new List<ServerClient>();
public List<ServerClient> disconnectList;
public List<CharactersOnline> charactersOnline = new List<CharactersOnline>();
public int port = 8080;
private TcpListener server;
private bool serverStarted;
private int connectionIncrementor;
private string mysqlConnectionString = #"server=xxx;userid=xxx;password=xxx;database=xx";
private MySqlConnection mysqlConn = null;
private MySqlDataReader mysqlReader;
static void Main(string[] args)
{
WorldServer serverInstance = new WorldServer();
Console.WriteLine("Starting World Server...");
try
{
serverInstance.mysqlConn = new MySqlConnection(serverInstance.mysqlConnectionString);
serverInstance.mysqlConn.Open();
Console.WriteLine("Connected to MySQL version: " + serverInstance.mysqlConn.ServerVersion + "\n");
}
catch (Exception e)
{
Console.WriteLine("MySQL Error: " + e.ToString());
}
finally
{
if (serverInstance.mysqlConn != null)
{
serverInstance.mysqlConn.Close();
}
}
serverInstance.clients = new List<ServerClient>();
serverInstance.disconnectList = new List<ServerClient>();
try
{
serverInstance.server = new TcpListener(IPAddress.Any, serverInstance.port);
serverInstance.server.Start();
serverInstance.StartListening();
serverInstance.serverStarted = true;
Console.WriteLine("Server has been started on port: " + serverInstance.port);
}
catch (Exception e)
{
Console.WriteLine("Socket error: " + e.Message);
}
new Thread(() =>
{
Thread.CurrentThread.IsBackground = true;
/* run your code here */
while (true)
{
string input = Console.ReadLine();
string[] commands = input.Split(':');
if (commands[0] == "show online players")
{
Console.WriteLine("Showing connections\n");
foreach (CharactersOnline c in serverInstance.charactersOnline)
{
Console.WriteLine("Character name: " + c.characterName + "Character ID: " + c.characterId + "Connection id: " + c.connectionId + "\n");
}
}
continue;
}
}).Start();
while (true)
{
serverInstance.Update();
}
}
private void Update()
{
//Console.WriteLine("Call");
if (!serverStarted)
{
return;
}
foreach (ServerClient c in clients.ToList())
{
// Is the client still connected?
if (!IsConnected(c.tcp))
{
c.tcp.Close();
disconnectList.Add(c);
Console.WriteLine(c.connectionId + " has disconnected.");
CharacterLogout(c.connectionId);
continue;
//Console.WriteLine("Check for connection?\n");
}
else
{
// Check for message from Client.
NetworkStream s = c.tcp.GetStream();
if (s.DataAvailable)
{
StreamReader reader = new StreamReader(s, true);
string data = reader.ReadLine();
if (data != null)
{
OnIncomingData(c, data);
}
}
//continue;
}
}
for (int i = 0; i < disconnectList.Count - 1; i++)
{
clients.Remove(disconnectList[i]);
disconnectList.RemoveAt(i);
}
}
private void OnIncomingData(ServerClient c, string data)
{
Console.WriteLine(data);
dynamic json = JsonConvert.DeserializeObject(data);
string header = json.header;
//Console.WriteLine("Conn ID:" + json.connectionId);
string connId = json.connectionId;
int.TryParse(connId, out int connectionId);
string prefix = header.Substring(0, 2);
if (prefix != "1x")
{
Console.WriteLine("Unknown packet: " + data + "\n");
}
else
{
string HeaderPacket = header.Substring(2);
switch (HeaderPacket)
{
default:
Console.WriteLine("Unknown packet: " + data + "\n");
break;
case "004":
int accountId = json.data["accountId"];
SelectAccountCharacters(accountId, connectionId);
break;
case "005":
int characterId = json.data["characterId"];
getCharacterDetails(characterId, connectionId);
break;
case "006":
int charId = json.data["characterId"];
SendDataForSpawningOnlinePlayers(charId, connectionId);
break;
case "008":
Dictionary<string, string> dictObj = json.data.ToObject<Dictionary<string, string>>();
UpdateCharacterPosition(dictObj, connectionId);
break;
}
}
private bool IsConnected(TcpClient c)
{
try
{
if (c != null && c.Client != null && c.Client.Connected)
{
if (c.Client.Poll(0, SelectMode.SelectRead))
{
return !(c.Client.Receive(new byte[1], SocketFlags.Peek) == 0);
}
return true;
}
else
{
return false;
}
}
catch
{
return false;
}
}
private void StartListening()
{
server.BeginAcceptTcpClient(OnConnection, server);
}
private void OnConnection(IAsyncResult ar)
{
connectionIncrementor++;
TcpListener listener = (TcpListener)ar.AsyncState;
clients.Add(new ServerClient(listener.EndAcceptTcpClient(ar)));
clients[clients.Count - 1].connectionId = connectionIncrementor;
StartListening();
//Send a message to everyone, say someone has connected!
Dictionary<string, string> SendDataBroadcast = new Dictionary<string, string>();
SendDataBroadcast.Add("connectionId", clients[clients.Count - 1].connectionId.ToString());
Broadcast("001", SendDataBroadcast, clients, clients[clients.Count - 1].connectionId);
Console.WriteLine(clients[clients.Count - 1].connectionId + " has connected.");
}
And this is how the server send back data to the client:
private void Send(string header, Dictionary<string, string> data, int cnnId)
{
foreach (ServerClient c in clients.ToList())
{
if (c.connectionId == cnnId)
{
try
{
//Console.WriteLine("Sending...");
StreamWriter writer = new StreamWriter(c.tcp.GetStream());
if (header == null)
{
header = "000";
}
JsonData SendData = new JsonData();
SendData.header = "0x" + header;
foreach (var item in data)
{
SendData.data.Add(item.Key.ToString(), item.Value.ToString());
}
SendData.connectionId = cnnId;
string JSonData = JsonConvert.SerializeObject(SendData);
writer.WriteLine(JSonData);
writer.Flush();
//Console.WriteLine("Trying to send data to connection id: " + cnnId + " data:" + sendData);
}
catch (Exception e)
{
Console.WriteLine("Write error : " + e.Message + " to client " + c.connectionId);
}
}
}
}
Here is my ServerClient class:
public class ServerClient
{
public TcpClient tcp;
public int accountId;
public int connectionId;
public ServerClient(TcpClient clientSocket)
{
tcp = clientSocket;
}
}
Can you please show me how i should modify my Send function on the client to send the data as byte array so i can create "TCP Message Framing" and how should i change my the following part on the server:
foreach (ServerClient c in clients.ToList())
{
// Is the client still connected?
if (!IsConnected(c.tcp))
{
c.tcp.Close();
disconnectList.Add(c);
Console.WriteLine(c.connectionId + " has disconnected.");
CharacterLogout(c.connectionId);
continue;
//Console.WriteLine("Check for connection?\n");
}
else
{
// Check for message from Client.
NetworkStream s = c.tcp.GetStream();
if (s.DataAvailable)
{
StreamReader reader = new StreamReader(s, true);
string data = reader.ReadLine();
if (data != null)
{
OnIncomingData(c, data);
}
}
//continue;
}
}
which is responsible for receving data on the server ?
Is it possible to change only these parts from the Client and on the Server and make it continue to work but this time properly with TCP Message Framing ?
Of course the listener on the client and the Send function of the server i'll remake once i understand how this framing should look like.

Your frames are already defined by cr/lf - so that much already exists; what you need to do is to keep a back buffer per stream - something like a MemoryStream might be sufficient, depending on how big you need to scale; then essentially what you're looking to do is something like:
while (s.DataAvailable)
{
// try to read a chunk of data from the inbound stream
int bytesRead = s.Read(someBuffer, 0, someBuffer.Length);
if(bytesRead > 0) {
// append to our per-socket back-buffer
perSocketStream.Position = perSocketStream.Length;
perSocketStream.Write(someBuffer, 0, bytesRead);
int frameSize; // detect any complete frame(s)
while((frameSize = DetectFirstCRLF(perSocketStream)) >= 0) {
// decode it as text
var backBuffer = perSocketStream.GetBuffer();
string message = encoding.GetString(
backBuffer, 0, frameSize);
// remove the frame from the start by copying down and resizing
Buffer.BlockCopy(backBuffer, frameSize, backBuffer, 0,
(int)(backBuffer.Length - frameSize));
perSocketStream.SetLength(backBuffer.Length - frameSize);
// process it
ProcessMessage(message);
}
}
}

C# Socket: Client Mishandle 'a' as the Client's id

There are two programs that I made that didn't work. There are the server and the client. The server accepts many client by giving a user an ID (starting from 0). The server sends out the command to the specific client based up the server's id. (Example: 200 client are connected to 1 server. The server's selected id is '5', so the server will send the command to all of the client, and the client will ask the server what ID he wants to execute his command on, and if it's '5', that client will execute and send data to the server). The client has many commands, but to create the smallest code with the same error, I only use 1 command (dir). Basically, the server sends the command to the client and if it matches with the client current id and the server current id, it will process the command. By default, the server's current ID is 10. Here are the list of the commands to help the people who wants to answer:
Server Command:
list (Shows all of the users ID connected and the server's current ID) --> Happens on server
dir (request the client to send its dir listing) --> Sent by the client, read by the Server
set (set the server's current id to any number) (example: 'set 4')
Client:
using System;
using System.Speech.Synthesis;
using System.Windows.Forms;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading;
using System.Net.Sockets;
using System.Net;
namespace clientControl
{
class Program
{
public static string directory = #"C:\";
public static int id = -10;
public static Socket sck = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
static void Main(string[] args)
{
Connect();
getSession();
ReadResponse(sck);
}
static byte[] readResponseFunc()
{
long fileSize = 0;
string fileSizeInString = null;
byte[] fileSizeInByteArray = new byte[1024];
int fileSizeLength = sck.Receive(fileSizeInByteArray);
for (int i = 0; i < fileSizeLength; i++)
{
fileSizeInString = fileSizeInString + (char)fileSizeInByteArray[i];
}
try
{
fileSize = Convert.ToInt64(fileSizeInString);
}
catch { Console.WriteLine(fileSizeInString); }
sck.Send(Encoding.ASCII.GetBytes("a"));
byte[] responseUnknown = new byte[1];
sck.Receive(responseUnknown);
if (Encoding.ASCII.GetString(responseUnknown) == "b")
{
byte[] dataInByteArray = new byte[fileSize];
int dataLength = sck.Receive(dataInByteArray);
return dataInByteArray;
}
return Encoding.ASCII.GetBytes("ERROR RESPONSE FUNC");
}
static void getSession()
{
byte[] message_1 = Encoding.ASCII.GetBytes("make_id");
sck.Send(Encoding.ASCII.GetBytes(message_1.Length.ToString()));
byte[] responseUnknown = new byte[1];
if (Encoding.ASCII.GetString(responseUnknown) == "a")
{
sck.Send(Encoding.ASCII.GetBytes("b"));
sck.Send(message_1);
}
byte[] receivedID = readResponseFunc();
id = Convert.ToInt32(Encoding.ASCII.GetString(receivedID));
}
static bool SocketConnected(Socket s)
{
bool part1 = s.Poll(1000, SelectMode.SelectRead);
bool part2 = (s.Available == 0);
if (part1 && part2)
return false;
else
return true;
}
static void ReadResponse(Socket sck)
{
while (true)
{
if (SocketConnected(sck) == true)
{
try
{
string response = Encoding.ASCII.GetString(readResponseFunc());
byte[] message_1 = Encoding.ASCII.GetBytes("get_id");
sck.Send(Encoding.ASCII.GetBytes(message_1.Length.ToString()));
byte[] responseUnknown = new byte[1];
if (Encoding.ASCII.GetString(responseUnknown) == "a")
{
sck.Send(Encoding.ASCII.GetBytes("b"));
sck.Send(message_1);
}
byte[] response_2InByteArray = readResponseFunc();
string response_2 = Encoding.ASCII.GetString(response_2InByteArray);
if (Convert.ToInt32(response_2) == id)
{
if (response == "dir")
{
string resultOfDirring = "Current Directory: " + directory + "\n\n";
string[] folderListingArray = Directory.GetDirectories(directory);
foreach (string dir in folderListingArray)
{
string formed = "DIRECTORY: " + Path.GetFileName(dir);
resultOfDirring = resultOfDirring + formed + Environment.NewLine;
}
string[] fileListingArray = Directory.GetFiles(directory);
foreach (var file in fileListingArray)
{
FileInfo fileInfo = new FileInfo(file);
string formed = "FILE: " + Path.GetFileName(file) + " - FILE SIZE: " + fileInfo.Length + " BYTES";
resultOfDirring = resultOfDirring + formed + Environment.NewLine;
}
byte[] message_11 = Encoding.ASCII.GetBytes(resultOfDirring);
sck.Send(Encoding.ASCII.GetBytes(message_11.Length.ToString()));
byte[] responseUnknown_11 = new byte[1];
if (Encoding.ASCII.GetString(responseUnknown_11) == "a")
{
sck.Send(Encoding.ASCII.GetBytes("b"));
sck.Send(message_11);
}
}
}
else { }
}
catch { if (SocketConnected(sck) == false) { Console.WriteLine("Client Disconnected: " + sck.RemoteEndPoint); break; }; }
}
else if (SocketConnected(sck) == false) { Console.WriteLine("Client Disconnected: " + sck.RemoteEndPoint); break; }
}
}
static void Connect()
{
while (true)
{
try
{
sck.Connect(IPAddress.Parse("127.0.0.1"), 80);
break;
}
catch { }
}
}
}
}
Server:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Net.Sockets;
using System.IO;
using System.Text;
using System.Threading;
namespace serverControl
{
class Program
{
public static int ftpNum = 1;
public static List<int> listOfClient = new List<int>();
public static TcpListener server = new TcpListener(IPAddress.Parse("127.0.0.1"), 80);
public static string message = null;
public static int id = 0;
public static int selected_id = 10;
static void Main(string[] args)
{
server.Start();
Thread startHandlingClientThread = new Thread(startHandlingClient);
startHandlingClientThread.Start();
while (true)
{
Console.Write(":> ");
string rawmessage = Console.ReadLine();
if (rawmessage == "list")
{
Console.WriteLine("SELECTED ID: " + selected_id);
Console.WriteLine("List of Clients ID:");
for (int i = 0; i < listOfClient.Count; i++)
{
Console.WriteLine(listOfClient[i]);
}
message = rawmessage+"PREVENT_REPETITION_IN_COMMAND";
}
else if (rawmessage.Contains("set ")) { int wantedChangeId = Convert.ToInt32(rawmessage.Replace("set ", "")); selected_id = wantedChangeId; message = rawmessage+ "PREVENT_REPETITION_IN_COMMAND"; }
else
{
message = rawmessage;
}
}
}
static byte[] readResponseFunc(Socket sck)
{
long fileSize = 0;
string fileSizeInString = null;
byte[] fileSizeInByteArray = new byte[1024];
int fileSizeLength = sck.Receive(fileSizeInByteArray);
for (int i = 0; i < fileSizeLength; i++)
{
fileSizeInString = fileSizeInString + (char)fileSizeInByteArray[i];
}
fileSize = Convert.ToInt64(fileSizeInString);
sck.Send(Encoding.ASCII.GetBytes("a"));
byte[] responseUnknown = new byte[1];
sck.Receive(responseUnknown);
if (Encoding.ASCII.GetString(responseUnknown) == "b")
{
byte[] dataInByteArray = new byte[fileSize];
int dataLength = sck.Receive(dataInByteArray);
return dataInByteArray;
}
return Encoding.ASCII.GetBytes("ERROR RESPONSE FUNC");
}
static void startHandlingClient()
{
while (true)
{
handleClient(server);
}
}
static void handleClient(TcpListener clientToAccept)
{
Socket sck = clientToAccept.AcceptSocket();
Thread myNewThread = new Thread(() => ReadResponse(sck));
myNewThread.Start();
}
static bool SocketConnected(Socket s)
{
bool part1 = s.Poll(1000, SelectMode.SelectRead);
bool part2 = (s.Available == 0);
if (part1 && part2)
return false;
else
return true;
}
static void ReadResponse(Socket sck)
{
Thread myNewThread = new Thread(() => SendtoClient(sck));
myNewThread.Start();
Thread.Sleep(2000);
while (true)
{
if (SocketConnected(sck) == true)
{
try
{
byte[] dataInByteArray = readResponseFunc(sck);
string response = Encoding.ASCII.GetString(dataInByteArray);
Console.WriteLine("res: " + response);
if (response != "make_id" && response != "get_id") { Console.WriteLine(response); }
if (response == "make_id")
{
Console.WriteLine("Someone wants an ID");
byte[] message_1 = Encoding.ASCII.GetBytes(id.ToString());
listOfClient.Add(id);
// START
sck.Send(Encoding.ASCII.GetBytes(message_1.Length.ToString()));
byte[] responseUnknown = new byte[1];
if (Encoding.ASCII.GetString(responseUnknown) == "a")
{
sck.Send(Encoding.ASCII.GetBytes("b"));
sck.Send(message_1);
}
id++;
}
if (response == "get_id")
{
byte[] message_1 = Encoding.ASCII.GetBytes(selected_id.ToString());
sck.Send(Encoding.ASCII.GetBytes(message_1.Length.ToString()));
byte[] responseUnknown = new byte[1];
if (Encoding.ASCII.GetString(responseUnknown) == "a")
{
sck.Send(Encoding.ASCII.GetBytes("b"));
sck.Send(message_1);
}
}
}
catch { if (SocketConnected(sck) == false) { Console.WriteLine("Client Disconnected: " + sck.RemoteEndPoint); break; }; }
}
else if (SocketConnected(sck) == false) { Console.WriteLine("Client Disconnected: " + sck.RemoteEndPoint); break; }
}
}
static void SendtoClient(Socket sck)
{
string tempmessage = null;
while (true)
{
if (SocketConnected(sck) == true)
{
if (tempmessage != message)
{
if (!message.Contains("PREVENT_REPETITION_IN_COMMAND"))
{
byte[] message_1 = Encoding.ASCII.GetBytes(message);
sck.Send(Encoding.ASCII.GetBytes(message_1.Length.ToString()));
byte[] responseUnknown = new byte[1];
if (Encoding.ASCII.GetString(responseUnknown) == "a")
{
sck.Send(Encoding.ASCII.GetBytes("b"));
sck.Send(message_1);
}
}
tempmessage = message;
}
}
else if (SocketConnected(sck) == false)
{ Console.WriteLine("Client Disconnected: " + sck.RemoteEndPoint); break; }
}
}
}
}
Problem:
The problem is within the GetSession or the ReadResponseFunc function. The client thinks that his ID received by the server is 'a' (it's suppose to be an integer). I don't want a solution that suggest me to use other libs or
the TcpClient class
Bounty:
I'll put up a bounty with no expiry time to those who solve the problem.

The logic in your code is very confusing. My question to you: Why are you sending 'a' and 'b' back and forth between the server and client? Is it some sort of confirmation that the message has been received?
Anyways, throughout the quick tests I've done just now, it seems that the problem is Line 59 of your server:
sck.Send(Encoding.ASCII.GetBytes("a"));
Here's what I figured out during testing:
Server executes.
Client executes.
Client sends server the length of "make_id" (Line 51 of client)
Client waits for a response to return.
Server reads the value and sends back 'a' (Line 59 of server)
You may want to spend some time to straighten out your protocol so it's less confusing and more organized. That would help people like me and you spot bugs much more easily.

The user 'Bobby' has already found your problem. Credits go to him.
I further suggest that you use less threads, as thread synchronisation needs some effort when doing it right: all data that is accessed from different threads must be secured by locks, so that no outdated values remain in the CPU caches. Use .net Monitor from the "threading synchronisation primitives" for that job.
About the threads themselves:
You should have only one thread in the server. This thread takes all clients from a list (secured by Monitor), in which they were added when connection attempts were received. On each client it checks for incoming messages, evaluates them and replies with own messages if needed.
The client also has just one thread, that will loop (dont forget a sleep in the loop or you will have 100% usage of the used CPU core), send messages when desired and wait for replies when messages were sent.
About the messages:
I already gave some proposals in a comment to Bobby's answer. I suggest you create a CMessage class that has a Serialize() and Deserialze() to create a byte array to send from the CMessage members (serializing the content) or vice versa filling the members from the received bytes. You then may use this class in both programs and you'll have common solution.

Reuse MQMessage object

I have this test code that listens for messages forever. If it gets one it prints it out. What I want to do is avoid having to construct a MQMessage object prior to each get(). How do i reuse a MQMessage for multiple calls to get()?
using System;
using IBM.WMQ;
namespace WMQ {
class Program {
static void Main(string[] args) {
string QueueManagerName = "A1PATA00";
string channelName = "ECACHE";
string connectionName = "A1PATA00.WORLDSPAN.COM(1414)";
var queueManager = new MQQueueManager(QueueManagerName, channelName, connectionName);
MQQueue get = queueManager.AccessQueue("SPLASH.ECAC.2", MQC.MQOO_INPUT_AS_Q_DEF | MQC.MQGMO_FAIL_IF_QUIESCING);
var gmo = new MQGetMessageOptions();
gmo.Options = MQC.MQGMO_FAIL_IF_QUIESCING | MQC.MQGMO_WAIT;
gmo.WaitInterval = 10000000;// wait time
// var queueMessage = new MQMessage(); <--- i want to do this new once!
while (true) {
var queueMessage = new MQMessage(); // <-- only works if I do this every time i do a get
get.Get(queueMessage, gmo);
var strReturn = queueMessage.ReadString(queueMessage.MessageLength);
Console.WriteLine(strReturn);
}
}
}
}

When I see questions like this, I shake my head. You do not
understand object oriented concepts in the .NET VM (framework) and
garbage collection.
Also, why don't you write pure C# code?
Finally, in a world where security is very important, your code does
not support either SSL/TLS and/or UserID & Password authentication.
(1) Please notice where I am defining the MQMessage object (very important).
There is basically no difference in memory usage or speed between the following 2 code snippets:
(A)
MQMessage msg = null;
while (true)
{
msg = new MQMessage();
get.Get(msg, gmo);
Console.WriteLine(msg.ReadString(msg.MessageLength));
}
(B)
MQMessage msg = new MQMessage();
while (true)
{
get.Get(msg, gmo);
Console.WriteLine(msg.ReadString(msg.MessageLength));
msg.ClearMessage();
msg.MessageId = MQC.MQMI_NONE;
msg.CorrelationId = MQC.MQCI_NONE;
}
I prefer (A) because it is cleaner and easier to read.
(2) When you use 'var', you are forcing the .NET framework to guess at what you are doing. Do pure object oriented programming.
i.e.
MQMessage msg = new MQMessage();
(3) Explicitly setting the channel name and connection name in the MQQueueManager does not allow setting of MQ security information. Also, do NOT use the MQEnvironment class as it is NOT thread safe. It is far better to put all the information in a Hashtable and pass the Hashtable to the MQQueueManager class. Here is a MQ .NET managed-mode example using a Hashtable for MQ connection information:
using System;
using System.Collections;
using System.Collections.Generic;
using System.Text;
using IBM.WMQ;
namespace MQTest02
{
class MQTest02
{
private Hashtable inParms = null;
private Hashtable qMgrProp = null;
private System.String qManager;
private System.String outputQName;
/*
* The constructor
*/
public MQTest02()
: base()
{
}
/// <summary> Make sure the required parameters are present.</summary>
/// <returns> true/false
/// </returns>
private bool allParamsPresent()
{
bool b = inParms.ContainsKey("-h") && inParms.ContainsKey("-p") &&
inParms.ContainsKey("-c") && inParms.ContainsKey("-m") &&
inParms.ContainsKey("-q");
if (b)
{
try
{
System.Int32.Parse((System.String)inParms["-p"]);
}
catch (System.FormatException e)
{
b = false;
}
}
return b;
}
/// <summary> Extract the command-line parameters and initialize the MQ variables.</summary>
/// <param name="args">
/// </param>
/// <throws> IllegalArgumentException </throws>
private void init(System.String[] args)
{
inParms = Hashtable.Synchronized(new Hashtable());
if (args.Length > 0 && (args.Length % 2) == 0)
{
for (int i = 0; i < args.Length; i += 2)
{
inParms[args[i]] = args[i + 1];
}
}
else
{
throw new System.ArgumentException();
}
if (allParamsPresent())
{
qManager = ((System.String)inParms["-m"]);
outputQName = ((System.String)inParms["-q"]);
qMgrProp = new Hashtable();
qMgrProp.Add(MQC.TRANSPORT_PROPERTY, MQC.TRANSPORT_MQSERIES_MANAGED);
qMgrProp.Add(MQC.HOST_NAME_PROPERTY, ((System.String)inParms["-h"]));
qMgrProp.Add(MQC.CHANNEL_PROPERTY, ((System.String)inParms["-c"]));
try
{
qMgrProp.Add(MQC.PORT_PROPERTY, System.Int32.Parse((System.String)inParms["-p"]));
}
catch (System.FormatException e)
{
qMgrProp.Add(MQC.PORT_PROPERTY, 1414);
}
if (inParms.ContainsKey("-u"))
qMgrProp.Add(MQC.USER_ID_PROPERTY, ((System.String)inParms["-u"]));
if (inParms.ContainsKey("-x"))
qMgrProp.Add(MQC.PASSWORD_PROPERTY, ((System.String)inParms["-x"]));
if (inParms.ContainsKey("-s"))
qMgrProp.Add(MQC.SECURITY_EXIT_PROPERTY, ((System.String)inParms["-s"]));
System.Console.Out.WriteLine("MQTest02:");
Console.WriteLine(" QMgrName ='{0}'", qManager);
Console.WriteLine(" Output QName ='{0}'", outputQName);
System.Console.Out.WriteLine("QMgr Property values:");
foreach (DictionaryEntry de in qMgrProp)
{
Console.WriteLine(" {0} = '{1}'", de.Key, de.Value);
}
}
else
{
throw new System.ArgumentException();
}
}
/// <summary> Connect, open queue, read a message, close queue and disconnect.
///
/// </summary>
/// <throws> MQException </throws>
private void testReceive()
{
MQQueueManager qMgr = null;
MQQueue queue = null;
int openOptions = MQC.MQOO_INPUT_AS_Q_DEF + MQC.MQOO_FAIL_IF_QUIESCING;
MQGetMessageOptions gmo = new MQGetMessageOptions();
MQMessage receiveMsg = null;
try
{
qMgr = new MQQueueManager(qManager, qMgrProp);
System.Console.Out.WriteLine("MQTest02 successfully connected to " + qManager);
queue = qMgr.AccessQueue(outputQName, openOptions, null, null, null); // no alternate user id
System.Console.Out.WriteLine("MQTest02 successfully opened " + outputQName);
receiveMsg = new MQMessage();
queue.Get(receiveMsg, gmo);
System.Console.Out.WriteLine("Message Data>>>" + receiveMsg.ReadString(receiveMsg.MessageLength));
}
catch (MQException mqex)
{
System.Console.Out.WriteLine("MQTest02 cc=" + mqex.CompletionCode + " : rc=" + mqex.ReasonCode);
}
catch (System.IO.IOException ioex)
{
System.Console.Out.WriteLine("MQTest02 ioex=" + ioex);
}
finally
{
try
{
queue.Close();
System.Console.Out.WriteLine("MQTest02 closed: " + outputQName);
}
catch (MQException mqex)
{
System.Console.Out.WriteLine("MQTest02 cc=" + mqex.CompletionCode + " : rc=" + mqex.ReasonCode);
}
try
{
qMgr.Disconnect();
System.Console.Out.WriteLine("MQTest02 disconnected from " + qManager);
}
catch (MQException mqex)
{
System.Console.Out.WriteLine("MQTest02 cc=" + mqex.CompletionCode + " : rc=" + mqex.ReasonCode);
}
}
}
/// <summary> main line</summary>
/// <param name="args">
/// </param>
// [STAThread]
public static void Main(System.String[] args)
{
MQTest02 mqt = new MQTest02();
try
{
mqt.init(args);
mqt.testReceive();
}
catch (System.ArgumentException e)
{
System.Console.Out.WriteLine("Usage: MQTest02 -h host -p port -c channel -m QueueManagerName -q QueueName [-u userID] [-x passwd] [-s securityExit]");
System.Environment.Exit(1);
}
catch (MQException e)
{
System.Console.Out.WriteLine(e);
System.Environment.Exit(1);
}
System.Environment.Exit(0);
}
}
}
To run MQTest02 using your information, it would be:
MQTest02.exe -h A1PATA00.WORLDSPAN.COM -p 1414 -m A1PATA00 -c ECACHE -q SPLASH.ECAC.2

In the IBM MQ Knowledge center page "ClearMessage method" it documents the following:
This method clears the data buffer portion of the MQMessage object.
Any Message Data in the data buffer is lost, because MessageLength,
DataLength, and DataOffset are all set to zero.
The Message Descriptor (MQMD) portion is unaffected; an application
might need to modify some of the MQMD fields before reusing the
MQMessage object. To set the MQMD fields back use New to replace the
object with a new instance.
In the IBM MQ Knowledge center page "MQMessage .NET class" it documents the following:
public byte[] MessageId {get; set;}
For an MQQueue.Get call, this field specifies the message identifier
of the message to be retrieved. Normally, the queue manager returns
the first message with a message identifier and correlation identifier
that match the message descriptor fields. Allow any message identifier
to match using the special value MQC.MQMI_NONE.
public byte[] CorrelationId {get; set;}
For an MQQueue.Get call, the correlation identifier of the message to
be retrieved. The queue manager returns the first message with a
message identifier and a correlation identifier that match the message
descriptor fields. The default value, MQC.MQCI_NONE, helps any
correlation identifier to match.
Try this:
var queueMessage = new MQMessage(); <--- i want to do this new once!
while (true) {
//var queueMessage = new MQMessage(); // <-- only works if I do this every time i do a get
queueMessage.ClearMessage();
queueMessage.MessageId = MQC.MQMI_NONE;
queueMessage.CorrelationId = MQC.MQCI_NONE;
get.Get(queueMessage, gmo);

ASP.NET: get external IP address

I developed site. I need to get IP of site visitors.
I try to use Request, but it have only internal IP:
Response.Write(Request.ServerVariables["REMOTE_ADDR"]);
I looked all keys in Server Variables collection - the same result:
foreach (string var in Request.ServerVariables)
{
Response.Write(Request[var]);
}
How can I get external IP address?

You can use it to get External (public) IP Address..
public static string getExternalIp()
{
try
{
string externalIP;
externalIP = (new WebClient()).DownloadString("http://checkip.dyndns.org/");
externalIP = (new Regex(#"\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}"))
.Matches(externalIP)[0].ToString();
return externalIP;
}
catch { return null; }
}

This it part of my implementation for WebTracking. So here you go a snippet for IpAddress retrieval. You can read more about the Server Variables at Wikipedia.
/// <summary>
/// Get ip address from request
/// </summary>
/// <param name="request"></param>
/// <returns></returns>
private string GetIpAddress(HttpRequest request)
{
if (request.ServerVariables.IsNull()) return null;
var _realAddress = request.ServerVariables[#"HTTP_X_FORWARDED_FOR"];
if (_realAddress.IsNullOrEmpty())
{
_realAddress = request.ServerVariables[#"HTTP_FORWARDED"];
}
if (_realAddress.IsNullOrEmpty())
{
_realAddress = request.ServerVariables[#"REMOTE_ADDR"];
}
return _realAddress;
}

Are you behind a load-balancer/proxy? If so, inspect the headers collection of the request for headers similar to X-FORWARDED-FOR.

You can use like this
String lstrIpAddress;
if (Request.ServerVariables["HTTP_X_FORWARDED_FOR"] != null || Request.ServerVariables["HTTP_CLIENT_IP"] != null)
lstrIpAddress = Request.ServerVariables["HTTP_X_FORWARDED_FOR"];
else
lstrIpAddress = Request.ServerVariables["REMOTE_ADDR"];

you can simply use this nuget package.
https://www.nuget.org/packages/IpPublicKnowledge/
easy and simple. here is an example :
// Get Public IP
var ip = IPK.GetMyPublicIp();
//Get all IP infos
var IPinfo = IPK.GetIpInfo(ip);
//print some info
Console.WriteLine("*--------------------------- IPK -----------------------------*");
Console.WriteLine("My public IP : " + IPinfo.IP);
Console.WriteLine();
Console.WriteLine("My ISP : " + IPinfo.isp);
Console.WriteLine();
Console.WriteLine("My Country : " + IPinfo.country);
Console.WriteLine();
Console.WriteLine("My Languages : ");
foreach (var lang in IPinfo.languages)
{
Console.WriteLine(" " + lang.Key + " : " + lang.Value);
}
Console.WriteLine("*-------------------------------------------------------------*");
Console.Read();