Async Queue - ensure your list of async tasks execute in order

This dart package ensures your pack of async tasks executes in order, one after the other.

Features

• (Normal Queue) Add multiple jobs into queue before firing
• (Auto Queue) Firing job as soon as any job is added to the queue
• (Both) Option to add queue listener that emits events that happen in the queue
• Retry when a job failed

Installing and import the library:

Like any other package, add the library to your pubspec.yaml dependencies:

dependencies:
    async_queue: <latest_version>

Then import it wherever you want to use it:

import 'package:async_queue/async_queue.dart';

Usage

1. Normal Queue

 final asyncQ = AsyncQueue();
  asyncQ.addJob((_) =>
      Future.delayed(const Duration(seconds: 1), () => print("normalQ: 1")));
  asyncQ.addJob((_) =>
      Future.delayed(const Duration(seconds: 4), () => print("normalQ: 2")));
  asyncQ.addJob((_) =>
      Future.delayed(const Duration(seconds: 2), () => print("normalQ: 3")));
  asyncQ.addJob((_) =>
      Future.delayed(const Duration(seconds: 1), () => print("normalQ: 4")));

  await asyncQ.start();

    // normalQ: 1
    // normalQ: 2
    // normalQ: 3
    // normalQ: 4

2. Auto Start Queue

final autoAsyncQ = AsyncQueue.autoStart();

  autoAsyncQ.addJob((_) =>
      Future.delayed(const Duration(seconds: 1), () => print("AutoQ: 1")));
  await Future.delayed(const Duration(seconds: 6));
  autoAsyncQ.addJob((_) =>
      Future.delayed(const Duration(seconds: 0), () => print("AutoQ: 1.2")));
  autoAsyncQ.addJob((_) =>
      Future.delayed(const Duration(seconds: 0), () => print("AutoQ: 1.3")));
  autoAsyncQ.addJob((_) =>
      Future.delayed(const Duration(seconds: 4), () => print("AutoQ: 2")));
  autoAsyncQ.addJob((_) =>
      Future.delayed(const Duration(seconds: 3), () => print("AutoQ: 2.2")));
  autoAsyncQ.addJob((_) =>
      Future.delayed(const Duration(seconds: 2), () => print("AutoQ: 3")));
  autoAsyncQ.addJob((_) =>
      Future.delayed(const Duration(seconds: 1), () => print("AutoQ: 4")));

    // AutoQ: 1
    // AutoQ: 1.2
    // AutoQ: 1.3
    // AutoQ: 2
    // AutoQ: 2.2
    // AutoQ: 3
    // AutoQ: 4

Add Queue Listener

  final asyncQ = AsyncQueue();

  asyncQ.addQueueListener((event) => print("$event"));

Tell queue to retry a job

    q.addJob(() async {
      try {
        //do something
      } catch (e) {
        q.retry();
      }
    },
    //default is 1
     retryTime: 3,
    );

Flutter use cases:

This package would be useful if you have multiple widgets in a screen or even in multiple screens that need to do some async requests that are related to each other.

For examples:

• To make one request from a widget wait for another request from another widget to finish.
• To avoid multiple requests from the front end hitting the backend in a short time, which would confuse the backend.

Code example:

 @override
  Widget build(BuildContext context) {
    final aQ = AsyncQueue.autoStart();
    return Scaffold(
      body: Column(
        children: [
          TextButton(
            onPressed: () async {aQ.addJob((_) => Future.delayed(const Duration(seconds: 2), () => print("job1 ")));},
            child: const Text('job1'),
          ),
          TextButton(
            onPressed: () async {aQ.addJob((_) => Future.delayed(const Duration(seconds: 4), () => print("jobs2")));},
            child: const Text('job2'),
          ),
          TextButton(
            onPressed: () async {aQ.addJob((_) => Future.delayed(const Duration(seconds: 1), () => print("job3")));},
            child: const Text('job3'),
          ),
        ],
      ),
    );
  }

Appreciate Your Feedbacks and Contributes

If you find anything need to be improve or want to request a feature. Please go ahead and create an issue in the Github repo