Websocket .net core detect when client looses internet connectivity #9053

 public async Task Invoke(HttpContext context)
if (context.WebSockets.IsWebSocketRequest)
	SocketUserObject socketUser = new SocketUserObject();
	if (_webSocketLogic.IsAuthorizedUser(context, ref socketUser, _operation))
		var connection = await _webSocketHandler.OnConnected(context, socketUser, _operation);
		if (connection != null)
			await _webSocketHandler.ListenConnection(connection);
			context.Response.StatusCode = 404;
		context.Response.StatusCode = 404;
   public async Task ListenConnection(WebSocketConnection connection)
var buffer = new byte[BufferSize];
	while (connection.WebSocket.State == WebSocketState.Open)
		var result = await connection.WebSocket.ReceiveAsync(
			 buffer: new ArraySegment<byte>(buffer),
			 cancellationToken: CancellationToken.None);
		if (result.MessageType == WebSocketMessageType.Text)
			var message = Encoding.UTF8.GetString(buffer, 0, result.Count);
			await ReceiveAsync(connection, message, _operation2);
		else if (result.MessageType == WebSocketMessageType.Close)
			await OnDisconnected(connection, _operation2);
catch (Exception ex)
	_logging.TraceError(ex, _operation);
_logging.TraceLog(System.Reflection.MethodInfo.GetCurrentMethod(), _operation, "after State ", connection.WebSocket.State.ToString());
And I have added in the startup the below:

    var webSocketOptions = new WebSocketOptions()
        KeepAliveInterval = TimeSpan.FromSeconds(1),
        ReceiveBufferSize = 4 * 1024
    app.UseWebSockets(webSocketOptions);
I also tried adding this to the web.config file created on Azure from Kudu console:
  <system.webServer>
        <webSocket  enabled="true"   receiveBufferLimit="4194304"  pingInterval="00:01:00">
        </webSocket>
   </system.webServer>
and this is my client :
  public void StartReceiving(int modulo)
    RunWebSockets().GetAwaiter().GetResult();
  private async Task RunWebSockets()
    var client = new ClientWebSocket();
        client.Options.SetRequestHeader("id_handset", "1");
        await client.ConnectAsync(new Uri(url), CancellationToken.None);
        Console.WriteLine("Connected!");
        var sending = Task.Run(async () =&gt;
            string line;
            if (client.State == WebSocketState.Open)
                SocketOperation.Start(_socketOperation, client);
        var receiving = Receiving(client);
        await Task.WhenAll(sending, receiving);
    catch (Exception ex)
        if (client.State == WebSocketState.Open)
            await client.CloseAsync(WebSocketCloseStatus.NormalClosure, "", CancellationToken.None);
        SocketOperation.StopConsole();
        RunWebSockets().GetAwaiter().GetResult();
  private async Task Receiving(ClientWebSocket client)
    var buffer = new byte[1024 * 4];
    while (true)
        var result = await client.ReceiveAsync(new ArraySegment&lt;byte&gt;(buffer), CancellationToken.None);
        if (result.MessageType == WebSocketMessageType.Text)
            Console.WriteLine(Encoding.UTF8.GetString(buffer, 0, result.Count));
        else if (result.MessageType == WebSocketMessageType.Close)
            await client.CloseAsync(WebSocketCloseStatus.NormalClosure, "", CancellationToken.None);
            SocketOperation.StopConsole();
            RunWebSockets().GetAwaiter().GetResult();
            //await client.CloseOutputAsync(WebSocketCloseStatus.NormalClosure, "", CancellationToken.None);
            break;
Document Details
⚠ Do not edit this section. It is required for docs.microsoft.com ➟ GitHub issue linking.
ID: a3b0cac1-adc7-434c-d867-6e28e39bdae7
Version Independent ID: 762efeed-010e-f422-03d0-22d6681b2851
Content: WebSockets support in ASP.NET Core
Content Source: aspnetcore/fundamentals/websockets.md
Product: aspnet-core
GitHub Login: @Rick-Anderson
Microsoft Alias: tdykstra