demonstrateSubscriptions function

Implementation

Future<void> demonstrateSubscriptions(StompClient client) async {
  print('\n📬 Example 2: Subscriptions and Message Delivery');

  // Subscribe to a destination
  final subscription = await client.subscribe(
    destination: '/topic/news',
    ackMode: StompAckMode.client,
    requestReceipt: true,
  );

  print('✅ Subscribed to /topic/news with ID: ${subscription.id}');

  // Listen for messages
  final messageCompleter = Completer<void>();
  late StreamSubscription messageSubscription;

  messageSubscription = subscription.messages.listen((message) async {
    print('📩 Received message:');
    print('   Message ID: ${message.messageId}');
    print('   Destination: ${message.destination}');
    print('   Content: ${message.body}');

    // Acknowledge the message
    if (message.requiresAck && message.ackId != null) {
      await client.ack(messageId: message.ackId!);
      print('✅ Message acknowledged');
    }

    messageCompleter.complete();
  });

  // Send a message to the subscribed destination
  await client.send(
    destination: '/topic/news',
    body: 'Breaking news: STOMP protocol working perfectly!',
    contentType: 'text/plain',
  );

  // Wait for the message to be received
  await messageCompleter.future.timeout(const Duration(seconds: 5));
  await messageSubscription.cancel();

  // Unsubscribe
  await client.unsubscribe(subscriptionId: subscription.id);
  print('✅ Unsubscribed from /topic/news');
}