service_provider.md

Flutter Service Provider Guide

Service Providers in Flutter Bond offer an innovative and structured approach to managing dependencies. This README is a comprehensive guide on how to leverage Service Providers for effective dependency management in your Flutter applications.

Table of Contents

• What is a Service Provider?
• Service Providers and GetIt
• Model Serialization in a Service Provider
• Service Providers Per Feature
• Third-Party Integrations
• Using Service Providers in Your App
• Future Enhancements
• Resources

What is a Service Provider?

A Service Provider in Flutter Bond is a class that registers dependencies in a project, managing instances of services and facilitating easy access throughout the application. A separate Service Provider is created for each feature, such as authentication or post management.

Basic structure:

class PackagesServiceProvider extends ServiceProvider {
  @override
  Future<void> register(GetIt it) async {
    it.registerLazySingleton(() => PackagesApiService(it()));
    it.registerFactory(() => PackagesCubit(it()));
  }
}

Service Providers and GetIt

Service Providers in Flutter Bond make use of GetIt, a service locator for Dart and Flutter. This ensures an organized and efficient way of accessing services and models from any point in the application.

Model Serialization in a Service Provider

Within a Service Provider, you can define how to convert a model from JSON to an object using the factories map. This approach centralizes the conversion logic, reducing boilerplate code and making it easier to maintain and scale.

Example:

class PackagesServiceProvider extends ServiceProvider with ResponseDecoding {
  @override
  Map<Type, JsonFactory> get factories => {
    Package: (json) => Package.fromJson(json),
    // Add other model factories as needed...
  };
}

The ResponseDecoding mixin leverages the factories map to translate JSON objects into their corresponding models.

Certainly! Let's consider the auth (authentication) feature as a real-world example:

Service Providers per Feature

In a Flutter application, especially one that scales, an organized project structure is invaluable. The auth feature, which handles user authentication, is a common and critical feature in many applications. Let's delve into how the project structure would look for this feature and understand why a dedicated service provider is essential:

auth/
│
├── data/
│   ├── models/
│   │   ├── user_model.dart
│   │   ├── token_model.dart
│   │   └── ...
│   │
│   ├── apis/
│   │   ├── auth_api.dart
│   │   ├── profile_api.dart
│   │   └── ...
│   │
│   └── feature_flags/
│       └── ...
│
└── presentations/
    ├── pages/
    │   ├── login_page.dart
    │   ├── register_page.dart
    │   └── ...
    │
    ├── views/
    │   ├── login_view.dart
    │   ├── register_view.dart
    │   └── ...
    │
    ├── providers/
    │   ├── login_form_controller.dart
    │   └── register_form_controller.dart
    │
    ├── routes/
    │   ├── auth_routes.dart
    │   └── ...
    │
    └── notifications/
        └── ...
│
└── auth_service_provider.dart

auth_service_provider.dart

class AuthServiceProvider extends ServiceProvider with ResponseDecoding {
  
  // Register all the services, models, APIs related to authentication
  @override
  Future<void> register(GetIt it) async {
    // APIs
    it.registerLazySingleton(() => AuthApi());
    it.registerLazySingleton(() => ProfileApi());
    
    // Providers (or controllers)
    it.registerFactory(() => LoginFormController(it()));
    it.registerFactory(() => RegisterFormController(it()));
  }

  // If you need any specific conversions for auth models from JSON
  @override
  Map<Type, JsonFactory> get factories => {
    UserModel: (json) => UserModel.fromJson(json),
    TokenModel: (json) => TokenModel.fromJson(json),
    // Add other model factories as needed...
  };
}

Third-Party Integrations

For third-party service integrations such as Firebase, create a dedicated Service Provider.

Firebase example:

import 'package:flutter_bond/core/services/service_provider.dart';
import 'package:firebase_core/firebase_core.dart';

class FirebaseServiceProvider extends ServiceProvider {
  @override
  Future<void> register(GetIt it) async {
    final firebaseApp = await Firebase.initializeApp();
    it.registerSingleton(firebaseApp);
  }
}

Using Service Providers in Your App

Once you've defined a Service Provider, register it within the app.dart file.

Example:

final List<ServiceProvider> providers = [
  FirebaseServiceProvider(),
  AppServiceProvider(),
  // ... other providers
];

Future Enhancements

We aim to employ code-generation tools to further automate the Service Provider creation process. This will enable developers to define configurations in dedicated files, from which the tool will generate the required Service Provider.

Resources

• JsonSerializable Package Documentation
• Flutter Official Documentation on JSON & Serialization

---

This updated guide reflects the new changes and provides clear instructions on how to implement the ResponseDecoding mixin and the factories map for JSON serialization within service providers.