Unity TCP client: connection to a server - unity3d

I have a hardware that streams data to a windows server, and I have IP and port of this server. Now I want to connect unity app as a TCP client to this server. I have tried many solutions, but still have hard time to figure out best way to do this. Any help is highly appreciated. One issue that I have with current tutorials is that most of them define a unity server and try to connect another unity app as client and mostly based on localhost. However, I just want to connect a unity app as a TCP client to a server which I have IP and port.
Warm regards,
enter image description here

First of all, at the top of your script:
using System;
using System.Net.Sockets;
Then, create an instance of TcpClient and begin the connection:
socket = new TcpClient
{
// dataBufferSize is in bytes
ReceiveBufferSize = dataBufferSize,
SendBufferSize = dataBufferSize
};
socket.BeginConnect(ip, port, ConnectCallback, socket);
In ConnectCallback():
private void ConnectCallback(IAsyncResult asyncResult)
{
socket.EndConnect(asyncResult);
if (!socket.Connected) return;
// stream is a NetworkStream you should declare somewhere
stream = socket.GetStream();
// receiveBuffer is a byte[] you should declare somewhere
receiveBuffer = new byte[dataBufferSize];
stream.BeginRead(receiveBuffer, 0, dataBufferSize, ReceiveCallback, null);
}
In ReceiveCallback():
private void ReceiveCallback(IAsyncResult asyncResult)
{
try
{
int byteLength = stream.EndRead(asyncResult);
if (byteLength <= 0)
{
// Disconnect client
return;
}
// Transfer data from receiveBuffer to data variable for handling
byte[] data = new byte[byteLength];
Array.Copy(receiveBuffer, data, byteLength);
// Handle data in any way you want to
// BeginRead again so you can keep receiving data
stream.BeginRead(receiveBuffer, 0, dataBufferSize, ReceiveCallback, null);
}
catch (Exception e)
{
Console.WriteLine($"Error receiving TCP data: {e.Message}");
}
}
I got this information from this tutorial.

Related

UWP - StreamSocket connection error for some connections

We have 2 UWP apps. One app shares data to the other app through StreamSocket. The server app will send data to client app. There will be 30-40 or more devices running the client app and connecting to the server's socket to receive data.
When we test with one client app, all the data sharing happens without any issue. But when we started testing with about 10 devices using the client app, sometimes some apps don't receive data. And there seems to be an error saying A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond
In general it get shared to most of the devices, but few fails sometimes randomly. What could be the reason for this? Is there a connection limit to connect to a socket with given IP and port using Stream Socket?
Here is some parts of our code. Please let me know what we have to correct here to avoid getting that error.
Server side
public async Task StartServer(string serverIp, string serverPort)
{
try
{
HostName serverAddress = new HostName(serverIp);
//Create a StreamSocketListener to start listening for TCP connections.
StreamSocketListener socketListener = new StreamSocketListener();
//Hook up an event handler to call when connections are received.
socketListener.ConnectionReceived += SocketListener_ConnectionReceived;
//Start listening for incoming TCP connections on the specified port.
await socketListener.BindEndpointAsync(serverAddress, serverPort);
}
catch (Exception e)
{
}
}
private async void SocketListener_ConnectionReceived(StreamSocketListener sender, StreamSocketListenerConnectionReceivedEventArgs args)
{
try
{
await Task.Run(() => ShareFile(args.Socket));
}
catch (Exception e)
{
}
}
Client side
public async Task ServerConnect(string serverIP, string serverPort)
{
try
{
HostName serverAddress = new HostName(serverIP);
StreamSocket socket = new StreamSocket();
socket.Control.KeepAlive = false;
// Connect to the server.
await socket.ConnectAsync(serverAddress, serverPort, SocketProtectionLevel.PlainSocket);
}
catch (Exception e)
{
}
}
Also would like to get these clarified
-What is the difference between BindServiceNameAsync and BindEndpointAsync? Most examples seems to use the first one. When should we use the second one?
-If we call sender.Dispose(); in SocketListener_ConnectionReceived, will that affect the other clients trying to join the same socket?
-In the ShareFile() function, if we close args.Socket() after sending data, can it close the socket before the client actually read the data from that side?

Xamarin Forms How to change Port or IPAddress of socket connection

I have a UWP (soon to be MacOS also) application that listens for incoming messages. The user can configure which IP Address and Port to listen on. Once the socket connection is listening, the user can also go back into the settings and change the IP Address or Port. I am trying to figure out how to shut down the existing listener and restart it using the new Port / IP Address when the user changes the values. Here is my code that starts the listener. Any help would be appreciated.
private static Socket iobj_listener;
public async static Task StartListening()
{
try
{
Debug.WriteLine("Point 1");
IPEndPoint localEndPoint = new IPEndPoint(ViewModelObjects.AppSettings.ServerIPAddress, ViewModelObjects.AppSettings.ServerPort);
// Create a TCP/IP socket.
iobj_listener = new Socket(ViewModelObjects.AppSettings.ServerIPAddress.AddressFamily,
SocketType.Stream, ProtocolType.Tcp);
// Bind the socket to the local endpoint and listen for incoming connections.
iobj_listener.Bind(localEndPoint);
iobj_listener.Listen(100);
ViewModelObjects.AppSettings.ListeningOnSocket = true;
while (true)
{
Debug.WriteLine("Point 2");
// Set the event to nonsignaled state.
allDone.Reset();
// Start an asynchronous socket to listen for connections.
Debug.WriteLine("Waiting for a connection on " + ViewModelObjects.AppSettings.ServerIPAddress.ToString() + "...");
iobj_listener.BeginAccept(
new AsyncCallback(AcceptCallback),
iobj_listener);
// Wait until a connection is made before continuing.
allDone.WaitOne();
}
}
catch (Exception e)
{
Debug.WriteLine(e.ToString());
}
finally
{
Debug.WriteLine("Point 3");
ViewModelObjects.AppSettings.ListeningOnSocket = false;
}
}
SO I could not find any quick answers so had to kind of figure this out on my own. If you see anything wrong with this, please let me know.
First of all I declared an e_Num as follows
public enum ge_SocketStatus
{
e_NotListening = 0,
e_Listening = 1,
e_Restart = 2
}
Then I added a StopListening function to my class that handles all my Socket communications and set the socket status to not listening as follows:
public static async Task StopListening()
{
try
{
if (iobj_listener.Connected)
{
//Wait till the connection ends or 30 seconds - this is so any last messages can be processed.
await Task.Delay(30000);
}
ViewModelObjects.AppSettings.SocketStatus = ge_SocketStatus.e_NotListening;
iobj_listener.Close(1);
}
catch (Exception ex)
{
App.AppException(ex);
}
}
I then use the value of this enum to know when to end the loop:
public async static Task StartListening()
{
try
{
Debug.WriteLine("Point 1");
IPEndPoint localEndPoint = new IPEndPoint(ViewModelObjects.AppSettings.ServerIPAddress, ViewModelObjects.AppSettings.ServerPort);
// Create a TCP/IP socket.
iobj_listener = new Socket(ViewModelObjects.AppSettings.ServerIPAddress.AddressFamily,
SocketType.Stream, ProtocolType.Tcp);
// Bind the socket to the local endpoint and listen for incoming connections.
iobj_listener.Bind(localEndPoint);
iobj_listener.Listen(100);
ViewModelObjects.AppSettings.SocketStatus = ge_SocketStatus.e_Listening;
while (ViewModelObjects.AppSettings.SocketStatus == ge_SocketStatus.e_Listening)
{
Debug.WriteLine("Point 2");
// Set the event to nonsignaled state.
allDone.Reset();
// Start an asynchronous socket to listen for connections.
Debug.WriteLine("Waiting for a connection on " + ViewModelObjects.AppSettings.ServerIPAddress.ToString() + "...");
iobj_listener.BeginAccept(
new AsyncCallback(AcceptCallback),
iobj_listener);
// Wait until a connection is made before continuing.
allDone.WaitOne();
}
}
catch (Exception e)
{
Debug.WriteLine(e.ToString());
}
finally
{
Debug.WriteLine("Point 3");
}
}
This line above
while (ViewModelObjects.AppSettings.SocketStatus == ge_SocketStatus.e_Listening)
used to be
while (true)
so the loop would never end.
One gotcha I found is in the AcceptCallback used in the BeginAccept function of my socket. In this code, I also had to detect if the socket was connected because this function is called one last time after the StartListening loop exits. At the point the socket is not connected so trying to do anything with is, such as EndAccept, causes the application to throw an exception. Below you can see where I added the line
if (listener.Connected)
in order to stop the code from crashing after I had closed the connection.
public static void AcceptCallback(IAsyncResult ar)
{
// Signal the main thread to continue.
allDone.Set();
// Get the socket that handles the client request.
Socket listener = (Socket)ar.AsyncState;
//If we have shut down the socket don't do this.
if (listener.Connected)
{
Socket handler = listener.EndAccept(ar);
// Create the state object.
StateObject state = new StateObject();
state.workSocket = handler;
handler.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
new AsyncCallback(ReadCallback), state);
}
}
Once all StopListening function ends and everything from the sockets is disconnected, I can call start listening again and open the socket on a different IPAddress and or Port.
I hope this helps as I could not find a good solution to this.

TCP Listener which should accept 100 threads per second

I have written code for TcpListener in c# which is supposed to receive request from client socket and process the request (send the processed request to our another web service to get final response) then parse the response and send the response back to client socket which initiated the request.
Code snippet below.
Code works fine when receive few requests at a time but now in order to move this to cloud and accept multiple request. We are testing this functionality by running JMeter test on same.
We are getting throughput like 4 when we hit 100 threads per seconds (end to end test - client system to server socket to our web service and back) which should be at least 30 to match client requirement.
If we omit the end to end flow and just send back to hardcode response from server socket itself we are seeing throughput 700.
To find the root cause I have added delay while sending hardcore response (same which we need to communicate with our web service) and I can see same behavior i.e. throughput drastically downgrades = 4/3.8
It means when TcpListener is busy processing existing request it may not attend the next requests (may be I am wrong in assumption - please correct if so)
Please have a look at code and help me increasing the performance .
public void StartTCPServer()
{
Logger.Write_Info_Log("In StartTCPServer - inPort : " + AESDK_CONFIG.PORT_NO, 1, log);
try
{
// Data buffer for incoming data.
byte[] bytes = new Byte[1024];
// Establish the local endpoint for the socket.
IPEndPoint localEndPoint = new IPEndPoint(IPAddress.Any, AESDK_CONFIG.PORT_NO);
// Create a TCP/IP socket.
Socket listener = new Socket(AddressFamily.InterNetwork,
SocketType.Stream, ProtocolType.Tcp);
// Bind the socket to the local endpoint and listen for incoming connections.
listener.Bind(localEndPoint);
listener.Listen(100);
while (true)
{
// Set the event to nonsignaled state.
allDone.Reset();
// Start an asynchronous socket to listen for connections.
listener.BeginAccept(
new AsyncCallback(AcceptCallback),
listener);
// Wait until a connection is made before continuing.
allDone.WaitOne();
}
}
catch (Exception Ex)
{
Logger.Write_Fatal_Log("Exception in Start Listening : " + Ex.Message, 1, log);
}
}
public void AcceptCallback(IAsyncResult ar)
{
// Signal the main thread to continue.
allDone.Set();
// Get the socket that handles the client request.
Socket listener = (Socket)ar.AsyncState;
Socket handler = listener.EndAccept(ar);
// Create the state object.
StateObject state = new StateObject();
state.workSocket = handler;
handler.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
new AsyncCallback(ReadCallback), state);
}
public void ReadCallback(IAsyncResult ar)
{
String strdata = String.Empty;
// Retrieve the state object and the handler socket
// from the asynchronous state object.
StateObject state = (StateObject)ar.AsyncState;
Socket handler = state.workSocket;
// Read data from the client socket.
int bytesRead = handler.EndReceive(ar);
if (bytesRead > 0)
{
// There might be more data, so store the data received so far.
state.sb.Append(Encoding.ASCII.GetString(
state.buffer, 0, bytesRead));
// Check for end-of-file tag. If it is not there, read
// more data.
strdata = state.sb.ToString();
if (!string.IsNullOrEmpty(strdata))
{
// All the data has been read from the client.
if (strdata.Contains("<<CheckConnection>>"))
{
log.Info(GlobalVar.gThreadNo(GlobalVar.gintCurrentThread) + "Data Received: " + strdata);
byte[] byData1 = System.Text.Encoding.UTF8.GetBytes("<<CheckConnectionAlive>>");
Send(handler, "<<CheckConnectionAlive>>");
}
else
{
Interlocked.Increment(ref m_clientCount);
//Process incoming requests here and send response back to client
string strResponse = GetRequest(strdata, m_clientCount);
Send(handler, strResponse);
}
}
else
{
// Not all data received. Get more.
handler.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
new AsyncCallback(ReadCallback), state);
}
}
}
private static void Send(Socket handler, String data)
{
// Convert the string data to byte data using ASCII encoding.
byte[] byteData = Encoding.ASCII.GetBytes(data);
// Begin sending the data to the remote device.
handler.BeginSend(byteData, 0, byteData.Length, 0,
new AsyncCallback(SendCallback), handler);
}
private static void SendCallback(IAsyncResult ar)
{
try
{
// Retrieve the socket from the state object.
Socket handler = (Socket)ar.AsyncState;
// Complete sending the data to the remote device.
int bytesSent = handler.EndSend(ar);
Console.WriteLine("Sent {0} bytes to client.", bytesSent);
handler.Shutdown(SocketShutdown.Both);
handler.Close();
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
}

UWP DatagramsSocket doesn't not fire MessageReceived

I'm working on a UWP application which should communicate via TCP/UDP to a remote device. My issue is that the UWP app successfully sends UDP messages to the remote device, but does not receive the replies.
Here follows the code extracted from the app (simplified):
async Task TestUdpIP()
{
// Writer to the DatagramSocket
DataWriter writer;
using (var udpClient = new DatagramSocket())
{
try
{
// UDP Socket binding
udpClient.MessageReceived += UdpClient_MessageReceived;
var controllerName = new Windows.Networking.HostName(controllerIpAddress.ToString());
await udpClient.BindEndpointAsync(controllerName, controllerIpPort.ToString());
var remoteHostName = new Windows.Networking.HostName(hostIpAddres.ToString());
await udpClient.ConnectAsync(remoteHostName, remoteHostPort.ToString());
// Create a message to send
string message = "Some message";
// Reset the counter of messages received back from the remote robot
messagesReceived = 0;
// Send the message
writer = new DataWriter(udpClient.OutputStream);
writer.WriteString(message);
await writer.StoreAsync();
// Wait for robot status messages
await Task.Delay(5000);
}
catch
{
}
}
}
void UdpClient_MessageReceived(DatagramSocket sender, DatagramSocketMessageReceivedEventArgs args)
{
// Just increment the number of messages received
messagesReceived++;
}
However the UdpClient_MessageReceived handler does not fire. I'm sure that UDP messages are correctly sent from the UWP app and that the remote device replies back as shown in the following screenshot from Wireshark (the test has been taken on the same PC where the UWP app is running)
.
(IP Address, Port) details are shown in the following list to better explain the picture above
UWP application: (192.168.1.108, 19000) to send and receive.
Remote device: (192.168.1.152, 15999) to receive and (192.168.1.152, 54697) to send
Note: this is a similar question, where the answer says that for whatever reason the DatagramSocket should fire some messages before being able to receive. In my example a message is sent out however the message received handler does not fire anyway.
Note: The UWP app has been granted the internet (client) and the internet (client and server) capabilities
Note: I've tried also this (more readable) approach to bind the inbound/outbound datagram socket on the UWP app obtaining the same results:
// UDP Socket binding
var controllerName = new HostName(controllerIpAddress.ToString());
var remoteHostName = new HostName(hostIpAddres.ToString());
EndpointPair endpointpar = new EndpointPair(controllerName,
controllerIpPort.ToString(),
remoteHostName,
remoteHostPort.ToString());
udpClient.MessageReceived += UdpClient_MessageReceived;
await udpClient.ConnectAsync(endpointpar);
Where is the issue? Many thanks!
Please try to also add the Private Networks (Client & Server) capability in your app's manifest.
On other hand, you can try the Official DatagramSocket sample to see whether the both devices can communicate with each other.
After some experimenting, I came out with the idea of using two different DatagramSocket instances: one to send out UDP messages, and one to listen for incoming messages. With this code, I've been able to send UDP messages to the remote device (as before) and also I've been able to receive UDP messages from the remote device.
async Task TestUdpIP_DifferentPorts()
{
// Writer to the DatagramSocket
DataWriter writer;
// Inbound and outbound DatagramSocket
DatagramSocket udpListener = new DatagramSocket();
DatagramSocket udpSender = new DatagramSocket();
try
{
// String containing the serializaed message
string serializedMessage = "Some message";
var controllerName = new HostName(controllerIpAddress.ToString());
var remoteHostName = new HostName(hostIpAddres.ToString());
// Bind listener
udpListener.MessageReceived += UdpClient_MessageReceived;
await udpListener.BindEndpointAsync(controllerName, controllerIpPort.ToString());
// Connect sender
await udpSender.ConnectAsync(remoteHostName, remoteHostPort.ToString());
// Reset the counter of messages received back from the remote robot
messagesReceived = 0;
// Send the message
writer = new DataWriter(udpSender.OutputStream);
writer.WriteString(JsonConvert.SerializeObject(message));
await writer.StoreAsync();
// Wait for robot status messages
await Task.Delay(1000);
}
catch (Exception ex)
{
// Some exception handling
}
udpSender.Dispose();
udpListener.Dispose();
}
void UdpClient_MessageReceived(DatagramSocket sender, DatagramSocketMessageReceivedEventArgs args)
{
// Just increment the number of messages received
messagesReceived++;
}
With this approach only the IP port (or service name) of the inbound listener needs to be specified. The framework will choose the next available outbound IP port.
Note: If I understand well the DatagramSocket.ConnectAsync(EndpointPair) documentation, the same DatagramSocket instance can be used to send and listen for incoming message, so I could not figure out the need for two different instances. From the documentation:
This ConnectAsync(EndPointPair) method on a DatagramSocket is used to define the local and remote endpoint where datagrams will be sent when using the OutputStream property. This method also restricts remote IP addresses of packets that will be accepted to the remote hostname in the endpointPair parameter. Only incoming packets that match the remote endpoint in the endpointPair parameter will trigger the MessageReceived event on the DatagramSocket.

Design choice for automatically reconnecting socket client

I'm working with a windows form application in C#. I'm using a socket client which is connecting in an asynchronous way to a server. I would like the socket to try reconnecting immediately to the server if the connection is broken for any reason. Which is the best design to approach the problem? Should I build a thread which is continuously checking if the connection is lost and tries to reconnect to the server?
Here is the code of my XcomClient class which is handling the socket communication:
public void StartConnecting()
{
socketClient.BeginConnect(this.remoteEP, new AsyncCallback(ConnectCallback), this.socketClient);
}
private void ConnectCallback(IAsyncResult ar)
{
try
{
// Retrieve the socket from the state object.
Socket client = (Socket)ar.AsyncState;
// Complete the connection.
client.EndConnect(ar);
// Signal that the connection has been made.
connectDone.Set();
StartReceiving();
NotifyClientStatusSubscribers(true);
}
catch(Exception e)
{
if (!this.socketClient.Connected)
StartConnecting();
else
{
}
}
}
public void StartReceiving()
{
StateObject state = new StateObject();
state.workSocket = this.socketClient;
socketClient.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0, new AsyncCallback(OnDataReceived), state);
}
private void OnDataReceived(IAsyncResult ar)
{
try
{
StateObject state = (StateObject)ar.AsyncState;
Socket client = state.workSocket;
// Read data from the remote device.
int iReadBytes = client.EndReceive(ar);
if (iReadBytes > 0)
{
byte[] bytesReceived = new byte[iReadBytes];
Buffer.BlockCopy(state.buffer, 0, bytesReceived, 0, iReadBytes);
this.responseList.Enqueue(bytesReceived);
StartReceiving();
receiveDone.Set();
}
else
{
NotifyClientStatusSubscribers(false);
}
}
catch (SocketException e)
{
NotifyClientStatusSubscribers(false);
}
}
Today I try to catch a disconnection by checking the number of bytes received or catching a socket exception.
If your application only receives data on a socket, then in most cases, you will never detect a broken connection. If you don't receive any data for a long time, you don't know if it's because the connection is broken or if the other end simply hasn't sent any data. You will, of course, detect (as EOF on the socket) connections closed by the other end in the normal fashion despite this.
In order to detect a broken connection, you need a keepalive. You need to either:
make the other end guarantee that it will send data on a set schedule, and you time out and close the connection if you don't get it, or,
send a probe to the other end once in a while. In this case the OS will take care of noticing a broken connection and you will get an error reading the socket if it's broken, either promptly (connection reset by peer) or eventually (connection timed out).
Either way, you need a timer. Whether you implement the timer as an event in an event loop or as a thread that sleeps is up to you and the best solution probably depends on how the rest of your application is structured. If you have a main thread that runs an event loop then it's probably best to hook in to that.
You can also enable the TCP keepalives option on the socket, but an application-layer keepalive is generally considered more robust.