config_manager 0.2.0

A JSON-based configuration manager with dot-notation access to nested values, singleton pattern, and mixin support.

example/main.dart

import 'package:config_manager/config_manager.dart';

class AppService with ConfigExtension {
  void printInfo() {
    print('--- Via ConfigExtension mixin ---');
    print('appName: ${get('appName')}');
    print('db host: ${get('database.host')}');
    print('db user: ${get('database.credentials.user')}');
    print('first feature: ${get('features.0')}');

    final servers = get('servers') as List? ?? [];
    for (final server in servers) {
      print('server via mixin: ${server['name']} (${server['region']})');
    }
  }
}

/// A custom [IConfigExtension] backed by an in-memory map instead of the
/// singleton. Only `get(key, {sector})` needs implementing; it is inherited
/// from [IConfigBase].
class InMemoryConfig implements IConfigExtension {
  final Map<String, dynamic> _store = {};

  @override
  dynamic get(String key, {String sector = kDefaultSector}) => _store[key];

  @override
  void loadFromMap(Map<String, dynamic> map, {String sector = kDefaultSector}) {
    _store
      ..clear()
      ..addAll(map);
  }

  @override
  void loadFromJson(String path, {String sector = kDefaultSector}) {}

  @override
  void loadFromString(String json, {String sector = kDefaultSector}) {}
}

void main() {
  final config = ConfigManagerSingleton();
  config.loadFromJson('example/config.json');

  print('--- Via ConfigManagerSingleton ---');

  print('appName: ${config.get('appName')}');

  print('db port: ${config.get('database.port')}');
  print('db user: ${config['database.credentials.user']}');

  print('--- Lists via casting ---');

  final features =
      (config.get('features') as List?)?.cast<String>() ?? [];
  print('features: $features');
  print('feature count: ${features.length}');

  for (final feature in features) {
    print('feature: $feature');
  }

  final servers = config.get('servers') as List? ?? [];
  for (final server in servers) {
    final map = server as Map<String, dynamic>;
    print('server: ${map['name']} -> ${map['region']}');
  }

  config.set('ports', [8080, 8081, 8082]);
  final ports = (config.get('ports') as List?)?.cast<int>() ?? [];
  print('ports: $ports');

  config.set('database.replicas', ['replica-1', 'replica-2']);
  print('nested list: ${config.get('database.replicas')}');

  print('--- Lists + dot notation ---');

  print('second feature: ${config.get('features.1')}');
  print('first server name: ${config.get('servers.0.name')}');
  print('second server region: ${config.get('servers.1.region')}');
  print('first replica: ${config.get('database.replicas.0')}');

  print('--- Writes and edge cases ---');

  config.set('database.credentials.password', 's3cret');
  print('written nested value: ${config.get('database.credentials.password')}');

  print('missing key: ${config.get('does.not.exist')}');
  print('index out of range: ${config.get('features.99')}');
  print('missing list: ${config.get('noSuchList') as List? ?? []}');

  print('--- Sectors ---');

  // Each sector loads its own file; when no sector is passed the
  // default sector is used.
  config.loadFromJson('example/config.json', sector: 'sales');
  print('loaded sectors: ${config.sectors.toList()}');
  print('sales appName: ${config.get('appName', sector: 'sales')}');
  print('default appName: ${config.get('appName')}');

  config.set('region', 'eu-west', sector: 'sales');
  print('sales region: ${config.get('region', sector: 'sales')}');

  AppService().printInfo();

  print('--- Via a custom IConfigExtension ---');

  final IConfigExtension custom = InMemoryConfig()
    ..loadFromMap({'appName': 'in-memory', 'level': 3});
  print('custom appName: ${custom.get('appName')}');
  print('custom level: ${custom.get('level')}');
}