launchpad 0.3.0

The missing dependency injection for Serverpod. Request-scoped and server-wide get_it containers for endpoints, streaming methods and future calls.

example/README.md

Launchpad example

A Serverpod 4 project using launchpad:

• example_server: the server. See server.dart, hello_endpoint.dart and visitor_report_future_call.dart.
• example_client: the generated client.
• example_flutter: a Flutter app calling the server.

Server setup

import 'package:launchpad/launchpad.dart';
import 'package:serverpod/serverpod.dart';

void run(List<String> args) async {
  final pod = Serverpod(args, Protocol(), Endpoints());

  // Server-wide dependencies, shared across all requests on this pod.
  Launchpad.initServerContext(pod, (getIt) {
    getIt.registerSingleton(ServerState());
  });

  await pod.start();

  // Schedule a future call. Its method is wrapped with `Launchpad.launch`, so
  // it can use the same server context as the endpoints.
  await pod.futureCalls
      .callWithDelay(const Duration(seconds: 10))
      .visitorReport
      .report('startup');
}

Request-scoped dependencies are registered with Launchpad.launchpadInit, see the package README.

Endpoint with a streaming method

class HelloEndpoint extends Endpoint {
  Future<String> hello(Session session) => Launchpad.launch(
    session,
    (context) async {
      final serverState = context.serverContext.get<ServerState>();
      serverState.counter += 1;
      return 'Hello from Serverpod! You are visitor number ${serverState.counter}.';
    },
  );

  Stream<String> countdown(Session session, int from) => Launchpad.launchStream(
    session,
    (context) async* {
      final serverState = context.serverContext.get<ServerState>();

      for (var i = from; i > 0; i--) {
        yield '$i... (visitors so far: ${serverState.counter})';
        await Future.delayed(const Duration(seconds: 1));
      }
      yield 'Liftoff!';
    },
  );
}

Future call

class VisitorReportFutureCall extends FutureCall {
  Future<void> report(Session session, String reason) => Launchpad.launch(
    session,
    (context) async {
      final serverState = context.serverContext.get<ServerState>();
      session.log('[$reason] Visitors so far: ${serverState.counter}');
    },
  );
}

Running it

cd example_server
docker compose up --build --detach
dart bin/main.dart