MQTT Connector

<MQTTConnector Name="MQTTConnector" 
               Path=":mqtt"
               Host="{Binding MQTTHost}"
               Port="{Binding MQTTPort}"
               Username="{Binding MQTTUser}"
               Password="{Binding MQTTPassword}"
               QoS="1"
               onConnect="handleConnect"
               onMessage="handleMessage"
               onError="handleError">
    
    <!-- Child components receive MQTT messages after processing -->
    <ChildComponent />
</MQTTConnector>

class MQTTConnector extends CoreElement {
    private client: mqtt.Client;
    
    constructor() {
        super();
        this.properties.set("host", "localhost");
        this.properties.set("port", 1883);
        this.properties.set("qos", 1);
    }

    async connect(): Promise<void> {
        this.client = mqtt.connect({
            host: this.properties.get("host"),
            port: this.properties.get("port"),
            username: this.properties.get("username"),
            password: this.properties.get("password")
        });

        this.client.on("message", async (topic, message) => {
            const event = new MiddlewareEvent("message", {
                topic,
                message: message.toString()
            });
            await this.routeEvent(event);
        });
    }

    async handleEvent(event: MiddlewareEvent): Promise<void> {
        if (event.type === "publish") {
            const { topic, message } = event.data;
            this.client.publish(topic, message);
        }
    }
}