dart user service, dependency injection with riverpod

backend-dart/lib/application/user_service/user_service.dart

@@ -0,0 +1,27 @@
+import 'package:backend_dart/infrastructure/persistence/database.dart';
+import 'package:shelf/shelf.dart';
+import 'package:shelf_router/shelf_router.dart';
+
+part 'user_service.g.dart'; // generated with 'pub run build_runner build'
+
+class UserService {
+  final Database database;
+  UserService(this.database);
+
+  @Route.get('/')
+  Future<Response> listUsers(Request request) async {
+    return Response.ok('["user1"]');
+  }
+
+  @Route.get('/<userId>')
+  Future<Response> fetchUser(Request request, String userId) async {
+    final result = await database.users.findById(userId);
+    if (result != null) {
+      return Response.ok(result);
+    }
+    return Response.notFound('no such user');
+  }
+
+  // Create router using the generate function defined in 'userservice.g.dart'.
+  Router get router => _$UserServiceRouter(this);
+}

backend-dart/lib/application/user_service/user_service.g.dart

@@ -0,0 +1,22 @@
+// GENERATED CODE - DO NOT MODIFY BY HAND
+
+part of 'user_service.dart';
+
+// **************************************************************************
+// ShelfRouterGenerator
+// **************************************************************************
+
+Router _$UserServiceRouter(UserService service) {
+  final router = Router();
+  router.add(
+    'GET',
+    r'/',
+    service.listUsers,
+  );
+  router.add(
+    'GET',
+    r'/<userId>',
+    service.fetchUser,
+  );
+  return router;
+}

backend-dart/lib/application/user_service/user_service_provider.dart

@@ -0,0 +1,8 @@
+import 'package:backend_dart/application/user_service/user_service.dart';
+import 'package:backend_dart/infrastructure/persistence/database_provider.dart';
+import 'package:riverpod/riverpod.dart';
+
+final userServiceProvider = Provider<UserService>((ref) {
+  final database = ref.read(databaseProvider);
+  return UserService(database);
+});