gate

Description:

gate

Gate #
Dart/Flutter Dependency injection generator








Motivation #
Providing Service should be independant from your pages or other code.
The DI pattern separates the responsibility of creating an object of the service class out of the client class.
Also using code generation we can get rid of the boilerplate part.
Features #

provide Injectable as a singleton
provide Injectable as a dynamic service
Inject an Injectable class into another

Getting started #
install gate with build_runner in you pubspec.yaml
dependencies:
build_runner: ^X.X.X
gate: ^X.X.X

dev_dependencies:
gate_generator: ^X.X.X
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replace X.X.X with last available version on pub.dev.

Usage #
1 - Create a class you want to inject #
import 'package:gate/gate.dart';

@Injectable()
class CoffeeService {
final S1 s1;

CoffeeService._(this.s1);

@Singleton()
factory CoffeeService.simple(S1 s1) => CoffeeService._(s1);

void pump() {
print("CoffeeService it's working");
}
}
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You just have to

add @Injectable() above your class
add @Singleton() or @Provide() above a factory

2 - inject dependency #
We can now inject our Injectables using @Inject annotation.
InjectedChild use

Type you want to inject
the name of the factory you want to use (you can have multiple provided factories)
the attribute name (just in case you want to rename it or make it private...)

import 'package:gate_example/gate/gate_provider.dart';
import 'package:gate_example/gate/coffee_service.dart';
part 'coffee_page.gate_inject.g.part';

@Inject(children: [
InjectedChild(S1, factoryName: "build"),
InjectedChild(CoffeeService, factoryName: "simple", attrName: "coffeeService"),
])
class CoffeePage extends StatelessWidget {
const CoffeePage({Key? key}) : super(key: key);

@override
Widget build(BuildContext context) {
coffeeService.pump();
return Container();
}
}
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You can inject as many dependency as you want into your class as long as their are Injectable.

part 'coffee_page.gate_inject.g.part'; will be be added to your file
this file will be genererated on next step
don't forget to import "gate_provider.dart" that is generated next

3 - generate code #
Using build runner you can run the command in your shell
flutter packages pub run build_runner build --delete-conflicting-outputs
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Once build runner is done, you can run your flutter app and use all injected class.

If you change your factory or wants to inject other class... just rerun the build_runner :)

Properties #



Annotation
Description




Injectable
mark a class as containing Singleton or Provide factories


Singleton
mark a factory as a Singleton Injectable


Provide
mark a factory as a Dymamic Injectable. Each time you inject will create a new instance of that class


Inject
mark a class to inject dependencies



Inject annotation #



Property
Description




children
a list of InjectedChild



InjectedChild annotation #



Property
Description




type
The type to inject


factoryName
The factory name to use


attrName
(optionnal) The attribute name to call it from your class



Mock an injected dependency for testing #
To remplace your service by mocks, you have to set them, before testing.
Gate will generate all methods for you.
First, declare your mocked services with your prefered libraries.
Then use the "appProvider" to set mocks.
Finally, don't forget to reset mocks by setting them to null.
class CoffeeServiceMock extends Mock implements CoffeeService {}

class S1ServiceMock extends Mock implements S1 {}

class S2BServiceMock extends Mock implements S2B {}

class TodoServiceMock extends Mock implements TodoService {}

void main() {
// Initialize mocks
final CoffeeService coffeeServiceMock = CoffeeServiceMock();
final S1 s1ServiceMock = S1ServiceMock();
final S2B s2BServiceMock = S2BServiceMock();
final TodoService todoServiceMock = TodoServiceMock();

group('Mock injection group', () {
setUp(() {
when(() => coffeeServiceMock.getMenu()).thenReturn("Best menu");
// Set injected services with mocks
appProvider.setCoffeeServiceSimpleMock(coffeeServiceMock);
appProvider.setS1BuildMock(s1ServiceMock);
appProvider.setS2BBuildMock(s2BServiceMock);
appProvider.setTodoServiceBeanMock(todoServiceMock);
});

tearDownAll(() {
// Remove mocks from appProvider (real ones will be used)
appProvider.setCoffeeServiceSimpleMock(null);
appProvider.setS1BuildMock(null);
appProvider.setS2BBuildMock(null);
appProvider.setTodoServiceBeanMock(null);
});

test('Test mocks injection', () async {
expect(appProvider.getCoffeeServiceSimple().getMenu(),
equals('Best menu')); // Mocked returned value

appProvider.setCoffeeServiceSimpleMock(null);

expect(appProvider.getCoffeeServiceSimple().getMenu(),
equals('No menu')); // True value (not mocked)
});
});
}
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Run tests #
dart pub global activate coverage
dart test --coverage="coverage"
format_coverage --lcov --in=coverage --out=coverage.lcov --packages=.packages --report-on=lib
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FAQ #
To be done



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