UnityAsyncAwaitObservableTest.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using UnityEngine;
using UniRx.Async;
using UnityEngine.Networking;
using UniRx;
using System.Collections;

namespace Assets.Scripts.Views
{
    public class TestAsync : MonoBehaviour
    {
        private readonly Subject<string> subscription = new Subject<string>();
        private readonly Subject<Unit> oncomplete_subscription = new Subject<Unit>();
        private async void Start()
        {
            Debug.Log("hoge");
            await Task.Run(() =>
            {
                foreach (var item in Enumerable.Range(0, 10))
                {
                    Debug.Log(item);
                }
            });
            Debug.Log("fuga");
            Debug.Log("yoti");

            #region 期待する動きではない

            //// Merge : after task / after task ..... / task1 / task2 / task3 
            //// Concat : task1 / after task / task2 / after task
            //Observable.WhenAll(
            ////Observable.Merge(
            ////Observable.Concat(
            //    Observable.Return(Unit.Default).Select(async _ => await HogeAsync("task1")),
            //    Observable.Return(Unit.Default).Select(async _ => await HogeAsync("task2")),
            //    Observable.Return(Unit.Default).Select(async _ => await HogeAsync("task3")),
            //    Observable.Return(Unit.Default).Select(async _ => await HogeAsync("task4")),
            //    Observable.Return(Unit.Default).Select(async _ => await HogeAsync("task5")),
            //    Observable.Return(Unit.Default).Select(async _ => await HogeAsync("task6")),
            //    Observable.Return(Unit.Default).Select(async _ => await HogeAsync("task7"))
            //)
            //.Do(_ => Debug.Log("after task"))
            //.Subscribe();

            #endregion

            // IE<T> -> IO<T>[1]
            Enumerable.Range(1, 10).ToObservable().Subscribe(x => Debug.Log(x));

            // FireAndForget
            Debug.Log("1. Before FF");
            subscription.Subscribe(x => Debug.Log($"4. {x}")).AddTo(this);
            Enumerable.Range(1, 10).ToObservable()
                .Do(_ => Debug.Log("2. During FF"))
                .Do(x => FireAndForget($"{x}"))
                .SelectMany(oncomplete_subscription)
                .Subscribe(_ => Debug.Log("5. AfterFireAndForget"))
                .AddTo(this);
            Debug.Log("3. After FF");

            // これをしたいだけの人生だった (2017 ではエラー)
            //await ToaruCotoutine(UnityWebRequest.Get("https://google.com"));
        }

        private async Task HogeAsync(string text)
        {
            var random = new System.Random();
            await Task.Delay(Mathf.Clamp(random.Next(), 100, 5000));
            Debug.Log($"{text}");
        }

        private async void FireAndForget(string text)
        {
            var random = new System.Random();
            await Task.Delay(Mathf.Clamp(random.Next(), 100, 5000));
            subscription.OnNext(text);

            if (text == "10")
            {
                oncomplete_subscription.OnNext(Unit.Default);
            }
        }

        private IEnumerator ToaruCotoutine(UnityWebRequest req)
        {
            var op = req.SendWebRequest();
            var text = req.downloadHandler.text;
            yield return null;
        }
    }
}