Database Integration

This tutorial connects an endpoint to a real database using sqlite3, registered through Revali's dependency injection. The same repository pattern applies to any database driver (Postgres, MySQL, etc.) -- swap the driver-specific calls inside the repository and everything else stays the same.

Add the driver#

dependencies:
  sqlite3: ^2.9.0

Write a repository#

The repository owns all database-specific code. Nothing outside it needs to know it's backed by SQLite:

import 'package:sqlite3/sqlite3.dart';

class TodoRepository {
  TodoRepository(this._db) {
    _db.execute('''
      CREATE TABLE IF NOT EXISTS todos (
        id INTEGER PRIMARY KEY AUTOINCREMENT,
        title TEXT NOT NULL
      );
    ''');
  }

  final Database _db;

  List<Map<String, Object?>> findAll() {
    final result = _db.select('SELECT id, title FROM todos ORDER BY id');

    return [
      for (final row in result) {'id': row['id'], 'title': row['title']},
    ];
  }

  int insert(String title) {
    _db.execute('INSERT INTO todos (title) VALUES (?)', [title]);
    return _db.lastInsertRowId;
  }
}

Register the connection and repository#

Open the database once and register both it and the repository as lazy singletons in configureDependencies. Because TodoRepository's constructor takes a dependency, register it with a closure that resolves Database from di -- a bare TodoRepository.new tear-off only works for constructors that take no arguments:

import 'package:revali_router/revali_router.dart';
import 'package:sqlite3/sqlite3.dart';

import '../lib/repos/todo_repository.dart';

@App()
final class MainApp extends AppConfig {
  MainApp() : super(host: 'localhost', port: 8080);

  @override
  Future<void> configureDependencies(DI di) async {
    di
      ..registerLazySingleton<Database>(sqlite3.openInMemory)
      ..registerLazySingleton<TodoRepository>(
        () => TodoRepository(di.get<Database>()),
      );
  }
}

Inject the repository into a controller#

Controller constructor parameters are resolved from DI automatically. Mark them with @Dep():

import 'package:revali_router/revali_router.dart';

import '../../lib/repos/todo_repository.dart';

@Controller('todos')
class TodoController {
  const TodoController({@Dep() required this.repo});

  final TodoRepository repo;

  @Get()
  List<Map<String, Object?>> list() => repo.findAll();

  @Post()
  Map<String, Object?> create(@Body(['title']) String title) {
    final id = repo.insert(title);
    return {'id': id, 'title': title};
  }
}

POST /todos with body {"title": "Buy milk"} inserts a row and returns {"id": 1, "title": "Buy milk"}. GET /todos lists every row inserted so far -- the same Database instance is reused across requests because it's registered as a lazy singleton, not recreated per request.

What's next?#

• Configure Dependencies — registration methods (registerSingleton, registerFactory, registerLazySingleton), the Inject marker for DI values inside annotations, and request-scoped dependencies for per-request state like transactions
• Body — binding and validating request bodies beyond a single field