使用反应式扩展以正确的顺序处理多个响应

本文关键字：顺序处理 响应 反应式 扩展 | 更新日期: 2023-09-27 18:18:27

>情况

我有一个系统，一个请求产生两个响应。请求和响应具有相应的可观察量：

IObservable<RequestSent> _requests;
IObservable<MainResponseReceived> _mainResponses;
IObservable<SecondResponseReceived> _secondaryResponses;

可以保证RequestSent事件发生早于MainResponseReceived和SecondaryResponseReceived但响应以随机顺序出现。

我有什么

最初我想要处理两个响应的处理程序，所以我压缩了可观察量：

_requests
    .SelectMany(async request =>
    {
        var main = _mainResponses.FirstAsync(m => m.Id == request.Id);
        var secondary = _secondaryResponses.FirstAsync(s => s.Id == request.Id);
        var zippedResponse = main.Zip(secondary, (m, s) => new MainAndSecondaryResponseReceived {
            Request = request,
            Main = m, 
            Secondary = s
        });
        return await zippedResponse.FirstAsync(); ;
    })
    .Subscribe(OnMainAndSecondaryResponseReceived);
<小时 />

我需要什么

现在我还需要处理MainResponseReceived，而无需等待 SecondaryResponseRecieved，并且必须保证 OnMainResponseRecieved 在调用 OnMainAndSecondaryResponseReceived 之前完成

请问如何定义这两个订阅？

测试用例 1：

  1. 发生RequestSent
  2. MainResponseReceived发生 -> OnMainResponseReceived 被调用
  3. SecondaryResponseReceive d 发生 -> 调用 OnMainAndSecondaryResponseReceived

测试用例 2：

  1. 发生RequestSent
  2. 发生SecondaryResponseReceived
  3. MainResponseReceived occurs -> OnMainResponseReceived 被称为 -> OnMainAndSecondaryResponseReceived 被调用

使用反应式扩展以正确的顺序处理多个响应

我认为你走在正确的轨道上。我会停止在所有异步的东西上胡思乱想 - 那只会让事情变得复杂。

请尝试以下查询：

var query =
    _requests
        .SelectMany(request =>
            _mainResponses.Where(m => m.Id == request.Id).Take(1)
                .Do(m => OnMainResponseReceived(m))
                .Zip(
                    _secondaryResponses.Where(s => s.Id == request.Id).Take(1),
                    (m, s) => new MainAndSecondaryResponseReceived()
                    {
                        Request = request,
                        Main = m, 
                        Secondary = s
                    }));
var subscription =
    query.Subscribe(x => OnMainAndSecondaryResponseReceived(x));

.Do(...)是代码中缺少的重要部分。它确保在OnMainAndSecondaryResponseReceived之前调用OnMainResponseReceived，无论主响应还是次要响应是先传入。

我用以下方法对此进行了测试：

Subject<RequestSent> _requestsSubject = new Subject<RequestSent>();
Subject<MainResponseReceived> _mainResponsesSubject = new Subject<MainResponseReceived>();
Subject<SecondResponseReceived> _secondaryResponsesSubject = new Subject<SecondResponseReceived>();
IObservable<RequestSent> _requests = _requestsSubject.AsObservable();
IObservable<MainResponseReceived> _mainResponses = _mainResponsesSubject.AsObservable();
IObservable<SecondResponseReceived> _secondaryResponses = _secondaryResponsesSubject.AsObservable();
_requestsSubject.OnNext(new RequestSent() { Id = 42 });
_mainResponsesSubject.OnNext(new MainResponseReceived() { Id = 42 });
_secondaryResponsesSubject.OnNext(new SecondResponseReceived() { Id = 42 });
_requestsSubject.OnNext(new RequestSent() { Id = 99 });
_mainResponsesSubject.OnNext(new MainResponseReceived() { Id = 99 });
_secondaryResponsesSubject.OnNext(new SecondResponseReceived() { Id = 99 });
相关文章：