diplomatic-quarter/lib/uitl/SignalRUtil.dart

import 'dart:io';

import 'package:flutter/cupertino.dart';
import 'package:http/io_client.dart';
import 'package:signalr_core/signalr_core.dart';

class SignalRUtil {
  String hubName;
  BuildContext context;

  SignalRUtil({@required this.hubName, @required this.context});

  HubConnection connectionBuilder;

  void startSignalRConnection() async {
    connectionBuilder = HubConnectionBuilder()
        .withUrl(
            hubName,
            HttpConnectionOptions(
              client: IOClient(HttpClient()..badCertificateCallback = (x, y, z) => true),
              logging: (level, message) => print(message),
            ))
        .build();

    await connectionBuilder.start();

    connectionBuilder.on('ReceiveMessage', (message) {
      handleIncomingMessage(message);
    });
  }

  void closeSignalRConnection() {
    connectionBuilder.stop();
  }

  void handleIncomingMessage(List<dynamic> message) {
    print(message.toString());
  }

  void sendMessage(List<dynamic> args) async {
    await connectionBuilder.invoke('SendMessage', args: args); //['Bob', 'Says hi!']
  }

  bool getConnectionState() {
    if (connectionBuilder.state == HubConnectionState.connected || connectionBuilder.state == HubConnectionState.connecting) return true;
    if (connectionBuilder.state == HubConnectionState.disconnected || connectionBuilder.state == HubConnectionState.disconnecting) return false;
  }
}