awsiot-4.js

func connectToAWSIoT(clientId: String!) {
        
        func mqttEventCallback(_ status: AWSIoTMQTTStatus ) {
            switch status {
            case .connecting: print("Connecting to AWS IoT")
            case .connected:
                print("Connected to AWS IoT")
                // Register subscriptions here
                // Publish a boot message if required
            case .connectionError: print("AWS IoT connection error")
            case .connectionRefused: print("AWS IoT connection refused")
            case .protocolError: print("AWS IoT protocol error")
            case .disconnected: print("AWS IoT disconnected")
            case .unknown: print("AWS IoT unknown state")
            default: print("Error - unknown MQTT state")
            }
        }
        
        // Ensure connection gets performed background thread (so as not to block the UI)
        DispatchQueue.global(qos: .background).async {
            do {
                print("Attempting to connect to IoT device gateway with ID = \(clientId)")
                let dataManager = AWSIoTDataManager(forKey: "kDataManager")
                dataManager.connectUsingWebSocket(withClientId: clientId,
                                                  cleanSession: true,
                                                  statusCallback: mqttEventCallback)
                
            } catch {
                print("Error, failed to connect to device gateway => \(error!)")
            }
        }
    }