dependency_injection library

Provides a dependency injection container for managing services and their lifetimes.

This library implements the dependency injection pattern inspired by Microsoft.Extensions.DependencyInjection, enabling loose coupling and testability through constructor injection.

Service Lifetimes

Services can be registered with three different lifetimes:

• Transient: A new instance is created each time it's requested
• Scoped: One instance per scope (typically per request)
• Singleton: A single instance shared across the application

Basic Usage

Register and resolve services:

final services = ServiceCollection()
  ..addSingleton<ILogger, ConsoleLogger>()
  ..addScoped<IDatabase, SqlDatabase>()
  ..addTransient<IEmailService, SmtpEmailService>();

final provider = services.buildServiceProvider();
final logger = provider.getRequiredService<ILogger>();

Keyed Services

Register multiple implementations with different keys:

services
  ..addKeyedSingleton<ICache, RedisCache>('redis')
  ..addKeyedSingleton<ICache, MemoryCache>('memory');

final redisCache = provider.getRequiredKeyedService<ICache>('redis');

Service Scopes

Create scoped services for request-scoped lifetimes:

await using((scope) async {
  final db = scope.serviceProvider.getRequiredService<IDatabase>();
  await db.saveChanges();
}, provider.createScope());