api_bloc 1.5.0

A Flutter library for managing API calls using the BLoC pattern. This library provides a set of classes and utilities to simplify API calls and manage state changes.

Api BLoC

A Flutter library for managing API calls using the BLoC pattern. This library provides a set of classes and utilities to simplify API calls and manage state changes.

Features

• Easily manage API calls and state changes using the BLoC pattern.
• Generic classes for handling various API states such as loading, success, and error.
• Customizable builder and listener functions to respond to state changes.
• Automatic disposal of the controller to prevent memory leaks.

Getting Started

To use this library, add api_bloc as a dependency in your pubspec.yaml file.

dependencies:
  api_bloc: ^1.5.0

Usage

• Create a subclass of [BlocController] with [BlocStates]. This library already provide you with FetchStates [loading, success, error] and SubmitStates [idle, loading, success, failed, error], But you can create custom state by extending [BlocStates].

Fetching Scenario

import 'package:api_bloc/api_bloc.dart';

class GetUserController extends FetchController {
  @override
  Future<void> request({List<Object> args = const []}) async {
    await Future.delayed(const Duration(seconds: 1));
    final response = await Dio().get('https://reqres.in/api/users/2');

    final model = GetUserModel.fromJson(response.data);
    emit(FetchSuccessState<GetUserModel>(data: model));
  }
}

• Put the controller inside [ApiBloc] widget.

import 'package:api_bloc/api_bloc.dart';

final controller = GetUserController();

ApiBloc.builder(
  controller: controller,
  builder: (context, state, child) {
    if (state is FetchSuccessState<UserModel>) {
      return Text('Username: ${state.data!.username}');
    } else if (state is FetchErrorState){
      return Text('Error occurred: ${state.message}');
    } else {
      return CircularProgressIndicator();
    }
  },
);

When the first time it initiate the controller, on fetching controller it's auto running the request function. But if you want to re run it, you can do it by calling

controller.run();

Submitting Scenario

import 'package:api_bloc/api_bloc.dart';

class CreateUserController extends SubmitController {
  @override
  // We're going to dispose it manually if we set it as false.
  bool get autoDispose => false;

  @override
  Future<void> request({List<Object> args = const []}) async {
    await Future.delayed(const Duration(seconds: 1));
    final response = await Dio().post('https://reqres.in/api/users/2',
        data: FormData.fromMap({"name": args[0], "job": args[1]}));

    if (response.statusCode == 201) {
      final model = CreateUserModel.fromJson(response.data);
      emit(SubmitSuccessState<CreateUserModel>(data: model));
    } else {
      emit(SubmitFailedState<Map<String, dynamic>>(
          data: response.data,
          message: "Expected response code output is 201"));
    }
  }
}

• Put the controller inside [ApiBloc] widget.

import 'package:api_bloc/api_bloc.dart';

final controller = CreateUserController();

ApiBloc(
  controller: controller,
  listener: (context, state) {
    if (state is SubmitSuccessState<CreateUserModel>) {
      snackbar(context, message: "Succesfully creating new user with id #${state.data!.id}");
    } else if (state is SubmitFailedState) {
      snackbar(context, message: "Failed because ${state.message}", color: Colors.grey);
    } else if (state is SubmitErrorState) {
      snackbar(context, message: state.message, color: Colors.red);
    }
  },
  builder: (context, state, child) {
    if (state is SubmitLoadingState) {
      return TextButton(text: "Loading ...");
    }  else {
      return TextButton(text: "Create", onPressed: () => controller.run());
    }
  },
);

Unlike the fetch controller, initial state of submit controller is idle state, so to run the request you need to trigger the controller.run() manually.

Using Extension

Now you can easily customize how your ApiBloc handles different state scenarios using these new extensions:

• onIdle: Handle SubmitIdleState and only work with SubmitController.
• onLoading: Handle FetchLoadingState and only work with FetchController or SubmitLoadingState that only work with SubmitController.
• onSuccess: Handle FetchSuccessState and only work with FetchController or SubmitSuccessState that only work with SubmitController.
• onFailed: Handle SubmitFailedState and only work with SubmitController.
• onError: Handle FetchErrorState and only work with FetchController or SubmitErrorState that only work with SubmitController.

import 'package:api_bloc/api_bloc.dart';

final controller = CreateUserController();

ApiBloc(
  controller: controller,
  child: TextButton(text: "Create", onPressed: () => controller.run()))
.onLoading(
  builder: (context, state, child) {
    return TextButton(text: "Loading ...");
  })
.onFailed(
  listener: (context, state, child) {
    snackbar(context, message: "Failed because ${state.message}", color: Colors.grey);
  })
.onSuccess<CreateUserModel>(
  listener: (context, state, child) {
    snackbar(context, message: "Succesfully creating new user with id #${state.data!.id}");
  })
.onError(
  listener: (context, state, child) {
    snackbar(context, message: state.message, color: Colors.red);
  })
.onState<BlocStates<Object>>(
  listener; (context, state) {
    snackbar(context, message: "You're in this custom state of ${state.runtimeType}");
  },
  builder: (context, state, child) {
    return Text("You're in this custom state of ${state.runtimeType}");
  }
);

Example

• https://github.com/Nialixus/api_bloc/tree/main/example/lib
• https://medium.com/@nialixus/flutter-simplifying-api-requests-with-api-bloc-library-17222128422e