A wrapper for all your repositories in Flutter. Used to parse responses from your datasources (remote; ie: API / local; ie: SqfLite) with a unified Resource class, making it easy to have the same logic throughout your application UIs.

base.repository.dart

import 'dart:async';

import 'package:expenza/constants/global.constants.dart';
import 'package:expenza/domain/resource.dart';
import 'package:expenza/utils/log.utils.dart';

const String _tag = 'BaseRepository';

/// Base Repository that wraps all the app's repositories.
///
/// Used to store some repetitive methods.
///
/// - author - @ehbc221
/// - version - 1.0.0
/// - last updated - June 8th, 2023
abstract class BaseRepository {
  /// Wrapper for basic remote datasource calls.
  ///
  /// Returns Success or Error depending on the Api call.
  Future<Resource<Res>> remoteDatasourceCall<Req, Res>({
    Future<Resource<Res>> Function(Req)? datasourceCall,
    Future<Resource<Res>> Function()? datasourceVoidCall,
    required StreamController<BaseStatus> controller,
    Req? data,
  }) async {
    logD(_tag, 'remoteDatasourceCall: called.');
    Resource<Res> response = ResourceError<Res>(
      message: defaultErrorMessage,
    );
    try {
      // Send request
      response = await ((data != null && datasourceCall != null
          ? datasourceCall.call(data)
          : (datasourceVoidCall != null
              ? datasourceVoidCall.call()
              : ResourceError<Res>(
                  message:
                      'Impossible to call this resource. Incomplete function.',
                ))) as Future<Resource<Res>>);
      // Check response and send emit corresponding event
      if (response is ResourceSuccess<dynamic>) {
        controller.add(BaseStatus.success);
      } else {
        controller.add(BaseStatus.error);
      }
      return response;
    } catch (exception) {
      logW(_tag, 'Catch exception: $exception');
      controller.add(BaseStatus.error);
      return response;
    }
  }

  /// Base DAO that wraps all the app's DAOs.
  ///
  /// Used to handle calls and error handling.
  Future<Resource<Res>> localDatasourceCall<Req, Res>({
    Future<Res> Function(Req)? datasourceCall,
    Future<Res> Function()? datasourceVoidCall,
    required StreamController<BaseStatus> controller,
    Req? data,
  }) async {
    logD(_tag, 'localDatasourceCall: called.');
    Resource<Res> response = Resource<Res>.error(
      detail: defaultErrorMessage,
    );
    try {
      // Send request
      if (data != null && datasourceCall != null) {
        Res result = await datasourceCall.call(data);
        controller.add(BaseStatus.success);
        return Resource<Res>.success(
          data: result,
          isFromNetwork: false,
        );
      } else if (datasourceVoidCall != null) {
        Res result = await datasourceVoidCall.call();
        controller.add(BaseStatus.success);
        return Resource<Res>.success(
          data: result,
          isFromNetwork: false,
        );
      } else {
        controller.add(BaseStatus.error);
        return Resource<Res>.error(
          isNetworkError: false,
          message: 'Impossible to call this resource. Incomplete function.',
        );
      }
    } catch (exception) {
      logW(_tag, 'Catch exception: $exception');
      controller.add(BaseStatus.error);
      return response;
    }
  }
}

Example

Assuming you want to switch between your remote and local datasources, depending on the network status of the user (online / offline).
You can call the repository and it handles formatting the response with the Resource wrapper class.

/// Create a budget.
  Future<Resource<Budget>> create(
    Budget budget, {
    bool isOffline = true,
  }) async {
    logD(_tag, 'create called.');
    if (isOffline) {
      return localDatasourceCall<Budget, Budget>(
        controller: _controller,
        datasourceCall: budgetDao.create,
        data: budget,
      );
    } else {
      return remoteDatasourceCall<Budget, Budget>(
        controller: _controller,
        datasourceCall: budgetDatasource.create,
        data: budget,
      );
    }
  }