RxData for Flutter (Riverpod)

RxData allows to delegate fetching and caching behavior for your data. Uses riverpod on the background. Inspired by Revolut's RxData library.

Install

flutter pub add rxdata

Usage

First, define DataDelegate object and specify Data type.

final delegateProvider = StateNotifierProvider<DataDelegate<ApiResponse>, Data<ApiResponse>>((ref) {
  return DataDelegate<ApiResponse>(
    fromNetwork: () async* {
      // [fromNetwork] can yield multiple values before closing. You can sequentially fetch data and 
      // and yield them step by step. You should however prevent infinite streams.
      final response = await getRequest();
      yield response;
    },
    fromStorage: () async {
      return loadFromSqlite('my_key');
    },
    toStorage: (value) async {
      await saveToSqlite(value, 'my_key');
    },
  );
});

Then use standard Riverpod methods to watch/read the data.

class ExampleWidget extends HookConsumerWidget {
  const ExampleWidget({Key? key}) : super(key: key);

  final DataDelegate<ApiResponse> dataDelegate;

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final state = ref.watch(delegateProvider);

    return Scaffold(
      body: Column(
        children: [
          if (state.isLoading) const CircularProgressIndicator(),
          if (state.hasError) Text(state.error!.toString()),
          if (state.hasValue) Text(state.value!.toString()),
        ],
      ),
    );
  }
}

Data class has 3 fields:

• value: e.g. ApiResponse or whatever data you need;
• error: optional error, you might have error and value at the same time because value is not deleted when error is thrown;
• isLoading: if you can expect value or error to change soon.

You can then call dataDelegate.reload() to fetch data again. Delegate will handle caching by itself, provided that you specified your callbacks.

See example project for full usage.