Compile time dependency injection using factories, implmented using source_gen package, so that it works in every platform. The advantages of this approach are are performance (no reflection needed) and full debuggability, as the generated sources are easy to read and well formatted.

Install

To use this package, add auto_factory and build_runner in the dev_dependencies section and the auto_factory package in the dependencies section of your pubspec.yaml file.

Then, run pub run build_runner build to generate the part files.

Table of contents

Basic usage

To make a class part of the dependecy tree annotate the class with the @Injectable() annotation. The library satisfies the dependency by creating a new instance and injecting to the default constructor the required dependencies.

Note that the injection will work only on default constructor with positional arguments. See example directory.

import 'package:auto_factory_annotation/auto_factory_annotation.dart';

part 'myfile.g.dart';

@Injectable()
class Component {
  final OtherDependency dep;

  Component(OtherDependency this.dep);

  void doSomething() {
    //...
  }
}

/// in another file:
final component = ComponentFactory().create();

component.doSomething();

Singletons

Using the @Singleton() annotation has the same effect as @Component() except that the instance is only created the first time. Then the same instance is returned every time

import 'package:auto_factory_annotation/auto_factory_annotation.dart';

part 'myfile.g.dart';

@Singleton()
class Component {
  final OtherDependency dep;

  Component(OtherDependency this.dep);

  void doSomething() {
    //...
  }
}

/// in another file:
final component = ComponentFactory().create();

component.doSomething();

Providers

Sometimes you don't have access to imported objects, so you can't annotate them to make it part of your dependency graph. In this case you can create a class annotated with @Provider() that extends @ProviderBase and implement the provide() method

import 'package:auto_factory_annotation/auto_factory_annotation.dart';

part 'myfile.g.dart';

@Provider()
class IpProvider extends ProviderBase<String> {

  @override
  FutureOr<String> provide() {
    return '127.0.0.1';
  }
}

And then mark the injected field with the @ProvidedBy() annotation like this:

import 'package:auto_factory_annotation/auto_factory_annotation.dart';

part 'myfile.g.dart';

@Component()
class Component {
  final String ip;

  Component(@ProvidedBy(IpProvider) String this.ip);

  void doSomething() {
    //...
  }
}

/// in another file:
final component = ComponentFactory().create();

component.doSomething();

Providers can have their dependencies resolved too with both component and other providers:

import 'package:auto_factory_annotation/auto_factory_annotation.dart';

part 'myfile.g.dart';

@Provider()
class IpProvider extends ProviderBase<String> {

  final Config config;

  IpProvider(this.config);

  @override
  FutureOr<String> provide() {
    return this.config ? '127.0.0.1' : '11.22.33.44';
  }
}

Example

The auto_factory/example directory contains a full example

Libraries

auto_factory_annotation