CSMSSimulator.cs

using System;
using System.Net;
using System.Net.WebSockets;
using System.Text;
using Newtonsoft.Json.Linq;

namespace ocpp;

public class CSMSSimulator 
{
  public CSMSSimulator(int port)
  {
    this.Start("http://localhost:"+port+"/");
  }
    private int count = 0;
      public async void Start(string listenerPrefix)
      {
          HttpListener listener = new HttpListener();
          listener.Prefixes.Add(listenerPrefix);
          listener.Start();
          Console.WriteLine("Listening...");
          
          while (true)
          {
              HttpListenerContext listenerContext = await listener.GetContextAsync();
              if (listenerContext.Request.IsWebSocketRequest)
              {
                  ProcessRequest(listenerContext);
              }
              else
              {
                  listenerContext.Response.StatusCode = 400;
                  listenerContext.Response.Close();
              }
          }
      }

             
        private async void ProcessRequest(HttpListenerContext listenerContext)
        {
            WebSocketContext webSocketContext = null;
            try
            {                
                webSocketContext = await listenerContext.AcceptWebSocketAsync(subProtocol: "ocpp1.6");
                Interlocked.Increment(ref count);
                Console.WriteLine("Processed: {0}", count);
            }
            catch(Exception e)
            {
                listenerContext.Response.StatusCode = 500;
                listenerContext.Response.Close();
                Console.WriteLine("Exception: {0}", e);
                return;
            }

            WebSocket webSocket = webSocketContext.WebSocket;                                           

            try
            {
                byte[] receiveBuffer = new byte[65535];

                while (webSocket.State == WebSocketState.Open)
                {
                    WebSocketReceiveResult receiveResult = await webSocket.ReceiveAsync(new ArraySegment<byte>(receiveBuffer), CancellationToken.None);

                    if (receiveResult.MessageType == WebSocketMessageType.Text)
                    {                    
                        string buf = Encoding.ASCII.GetString(receiveBuffer);
                        buf = buf.Replace('\0', ' ').Trim();
                    }
                }
            }
            catch(Exception e)
            {
                Console.WriteLine("Exception: {0}", e);
            }
            finally
            {
                if (webSocket != null)
                    webSocket.Dispose();
            }
        }

}