flutter_dio_queue #

A lightweight yet robust request queue built on top of Dio. It provides automatic retries with backoff, prioritisation, rate limiting and offline awareness. Jobs can be persisted to disk and restored on the next app launch.

Features #

• Queue and prioritise requests made with Dio
• Automatic retry with exponential backoff and jitter
• Optional rate limiting using a token bucket
• Offline detection with automatic pause/resume
• In-memory or persistent Hive based storage
• Simple metrics and event stream for monitoring

Installation #

Add flutter_dio_queue to your pubspec.yaml. If you plan to use the persistent HiveQueueStorage, include hive_flutter and initialize Hive with Hive.initFlutter():

dependencies:
  flutter_dio_queue: ^0.1.3
  hive_flutter: ^1.1.0 # required for HiveQueueStorage

Then import the packages:

import 'package:flutter_dio_queue/flutter_dio_queue.dart';
import 'package:hive_flutter/hive_flutter.dart';

Usage #

Create a FlutterDioQueue and enqueue requests. Jobs will be executed according to the supplied configuration. When using the persistent HiveQueueStorage, ensure Hive is initialized before constructing the queue:

import 'package:dio/dio.dart';
import 'package:flutter_dio_queue/flutter_dio_queue.dart';
import 'package:hive_flutter/hive_flutter.dart';

Future<void> main() async {
  await Hive.initFlutter();
  final dio = Dio(BaseOptions(baseUrl: 'https://api.example.com'));
  final queue = FlutterDioQueue(
    dio: dio,
    config: QueueConfig(
      maxConcurrent: 3,
      policy: QueuePolicy.fifo,
      autoStart: true,
      retry: RetryPolicy(
        maxAttempts: 4,
        baseDelay: const Duration(milliseconds: 400),
        jitter: 0.25,
      ),
      rateLimit: RateLimit(10, const Duration(seconds: 1)),
      persist: true,
      deduplicate: true,
    ),
    storage: HiveQueueStorage(boxName: 'fdq_jobs'),
  );

  final jobId = queue.enqueueRequest(
    method: HttpMethod.post,
    url: '/notes',
    data: {'title': 'Hello'},
  );

  queue.events.listen((e) {
    debugPrint('Queue: $e');
    if (e.response != null) {
      debugPrint('Response data: ${e.response!.data}');
    }
  });

  // When `autoStart` is set to `false`, explicitly start processing:
  // queue.start();

  // You can also pause/resume or wait for completion with:
  // queue.pause();
  // queue.resume();
  // await queue.drain();
}

Interceptor #

You can divert selected Dio requests into the queue using the provided QueueInterceptor. When added, requests containing the x-queue: true header will be enqueued instead of executed immediately.

dio.interceptors.add(QueueInterceptor(queue));

Example #

See the example/ directory for a complete runnable demo and the test/ folder for additional usage scenarios.