async udp class for Unity

UdpConnection.cs

// taken from https://forum.unity.com/threads/simple-udp-implementation-send-read-via-mono-c.15900/#post-3645256

using System;
using System.Collections.Generic;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;
using UnityEngine;
 
public class UdpConnection
{
    private UdpClient udpClient;
 
    private readonly Queue<string> incomingQueue = new Queue<string>();
    Thread receiveThread;
    private bool threadRunning = false;
    private string senderIp;
    private int senderPort;
 
    public void StartConnection(string sendIp, int sendPort, int receivePort)
    {
        try { udpClient = new UdpClient(receivePort); }
        catch (Exception e)
        {
            Debug.Log("Failed to listen for UDP at port " + receivePort + ": " + e.Message);
            return;
        }
        Debug.Log("Created receiving client at ip  and port " + receivePort);
        this.senderIp = sendIp;
        this.senderPort = sendPort;
 
        Debug.Log("Set sendee at ip " + sendIp + " and port " + sendPort);
 
        StartReceiveThread();
    }
 
    private void StartReceiveThread()
    {
        receiveThread = new Thread(() => ListenForMessages(udpClient));
        receiveThread.IsBackground = true;
        threadRunning = true;
        receiveThread.Start();
    }
 
    private void ListenForMessages(UdpClient client)
    {
        IPEndPoint remoteIpEndPoint = new IPEndPoint(IPAddress.Any, 0);
 
        while (threadRunning)
        {
            try
            {
                Byte[] receiveBytes = client.Receive(ref remoteIpEndPoint); // Blocks until a message returns on this socket from a remote host.
                string returnData = Encoding.UTF8.GetString(receiveBytes);
 
                lock (incomingQueue)
                {
                    incomingQueue.Enqueue(returnData);
                }
            }
            catch (SocketException e)
            {
                // 10004 thrown when socket is closed
                if (e.ErrorCode != 10004) Debug.Log("Socket exception while receiving data from udp client: " + e.Message);
            }
            catch (Exception e)
            {
                Debug.Log("Error receiving data from udp client: " + e.Message);
            }
            Thread.Sleep(1);
        }
    }
 
    public string[] getMessages()
    {
        string[] pendingMessages = new string[0];
        lock (incomingQueue)
        {
            pendingMessages = new string[incomingQueue.Count];
            int i = 0;
            while (incomingQueue.Count != 0)
            {
                pendingMessages[i] = incomingQueue.Dequeue();
                i++;
            }
        }
 
        return pendingMessages;
    }
 
    public void Send(string message)
    {
        Debug.Log(String.Format("Send msg to ip:{0} port:{1} msg:{2}",senderIp,senderPort,message));
        IPEndPoint serverEndpoint = new IPEndPoint(IPAddress.Parse(senderIp), senderPort);
        Byte[] sendBytes = Encoding.UTF8.GetBytes(message);
        udpClient.Send(sendBytes, sendBytes.Length, serverEndpoint);
    }
 
    public void Stop()
    {
        threadRunning = false;
        receiveThread.Abort();
        udpClient.Close();
    }
}

Use Example

private UdpConnection connection;
 
    void Start()
    {
        string sendIp = "127.0.0.1";
        int sendPort = 8881;
        int receivePort = 11000;
 
        connection = new UdpConnection();
        connection.StartConnection(sendIp, sendPort, receivePort);
    }
 
    void Update()
    {
        foreach (var message in connection.getMessages()) Debug.Log(message);
 
        connection.Send("Hi!");
    }
 
    void OnDestroy()
    {
        connection.Stop();
    }