rpc_notify

Topic-based async push notifications built on rpc_dart. A server publishes events to named topics; clients subscribe and receive a Stream<NotifyEvent> over any IRpcTransport (WebSocket, HTTP/2, isolate, in-memory).

Delivery is fire-and-forget: events are pushed live to currently-connected subscribers only. There is no persistence, backlog, replay, cursor, or acknowledgement — a subscriber receives only events published while it is subscribed.

Quick start

In-memory (tests / single process)

import 'package:rpc_notify/rpc_notify.dart';

Future<void> main() async {
  final env = await NotifyServiceFactory.inMemory();

  env.subscriber.subscribe('orders').listen((e) => print(e.payload));
  env.publisher.publish('orders', {'id': '42'});

  await env.dispose();
}

Server

final server = NotifyServiceFactory.createServer(
  transport: transport, // any IRpcTransport
  // repository: await RedisNotifyRepository.connect(...), // optional backend
);
await server.start();

Client

final subscriber = NotifyServiceFactory.createSubscriber(transport: transport);
final publisher = NotifyServiceFactory.createPublisher(transport: transport);

final sub = subscriber.subscribe('orders').listen((e) => print(e.payload));
publisher.publish('orders', {'id': '42'});

await subscriber.unsubscribe('orders');
await subscriber.dispose();
await publisher.close();

Concepts

• Topic — a plain String channel. Events are isolated per topic.
• publish(topic, payload) — broadcast to every subscriber of the topic.
• publishTo(clientId, topic, payload) — deliver to a single client only.
• NotifyEvent — { topic, payload, timestamp, eventId? }; payload is a JSON-serializable Map<String, dynamic>.
• Direct vs RPC — inside a server process use INotifyPublisher.repository(repo) / INotifySubscriber.repository(repo) for a zero-round-trip path; remote processes use the .endpoint(...) variants (what the factory wires up). DirectNotifyServiceEnvironment bundles both around an in-memory repository with no transport or serialization at all.

Backends

The server routes events through an INotifyRepository. The default is InMemoryNotifyRepository (single process). For fan-out across replicas, inject a shared backend:

• rpc_notify_postgres — PostgreSQL LISTEN/NOTIFY.
• rpc_notify_redis — Redis Pub/Sub.

Both are stateless relays with the same semantics as the in-memory backend, just delivered across processes.

Custom backend

Implement INotifyRepository (7 methods: publish, publishTo, subscribe, unsubscribe, activeTopics, subscriberCount, dispose) and pass it to NotifyServiceFactory.createServer(repository: ...).