Continuum Store Sembast

Sembast-backed EventStore implementation for Continuum. Events are persisted locally using Sembast and survive app restarts.

Installation

dependencies:
  continuum: latest
  continuum_event_sourcing: latest
  continuum_store_sembast: latest
  sembast: ^3.8.6

Usage

import 'package:continuum_event_sourcing/continuum_event_sourcing.dart';
import 'package:continuum_store_sembast/continuum_store_sembast.dart';
import 'package:sembast/sembast_io.dart';
import 'continuum.g.dart'; // Generated

void main() async {
  // Open the Sembast event store
  final eventStore = await SembastEventStore.openAsync(
    databaseFactory: databaseFactoryIo,
    dbPath: '/path/to/events.db',
  );

  final store = EventSourcingStore(
    eventStore: eventStore,
    targets: $aggregateList,
  );

  // Use your aggregates
  final userId = StreamId('user-1');
  final session = store.openSession();
  await session.applyAsync<User>(
    userId,
    UserRegistered(userId: userId.value, name: 'Alice', email: 'alice@example.com'),
  );
  await session.saveChangesAsync();

  // Events are persisted - survive app restart
  final readSession = store.openSession();
  final user = await readSession.loadAsync<User>(userId);
}

When to Use

Good for:

• Flutter mobile apps (offline-first, no native plugins needed)
• Desktop applications
• Web applications (via sembast_web)
• Local-first architectures
• Cross-platform persistence with a pure Dart solution

Not suitable for:

• Multi-user backends (use a proper database)
• Large-scale event stores (Sembast loads the database into memory)

API

SembastEventStore.openAsync()

Opens or creates a Sembast database for event storage.

final eventStore = await SembastEventStore.openAsync(
  databaseFactory: databaseFactoryIo,
  dbPath: 'events.db',
);

The databaseFactory parameter lets you choose the storage backend:

• databaseFactoryIo from package:sembast/sembast_io.dart for Dart VM / Flutter.
• databaseFactoryWeb from package:sembast_web/sembast_web.dart for Flutter Web.

Closing the Store

Close when your app shuts down:

await eventStore.closeAsync();

Example

See example/lib/main.dart for a complete example with two aggregates.