在Web API控制器(.net Core)中使用异步/等待或任务

本文介绍了在Web API控制器( Core)中使用异步/等待或任务的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我有一个核心API，该API具有一个控制器，该控制器可构建要返回的聚合对象. 它创建的对象由来自对服务类的3个方法调用的数据组成.这些都彼此独立，并且可以彼此隔离地运行. 目前，我正在使用任务来改善此控制器的性能.当前版本看起来像这样...

I have a core API which has a controller that builds an aggregated object to return. the object it creates is made of data that comes from 3 method calls to a service class. These are all independent of each other and can be run in isolation from each other. Currently I am using tasks to improve the performance of this controller. the current version looks something like this...

[HttpGet] public IActionResult myControllerAction() { var data1 = new sometype1(); var data2 = new sometype2(); var data3 = new List<sometype3>(); var t1 = new Task(() => { data1 = service.getdata1(); }); t1.Start(); var t2 = new Task(() => { data2 = service.getdata2(); }); t2.Start(); var t3 = new Task(() => { data3 = service.getdata2(); }); t3.Start(); Task.WaitAll(t1, t2, t3); var data = new returnObject { d1 = data1, d2 = data2, d2 = data3 }; return Ok(data); }

这很好用，但是我想知道使用任务是否是这里最好的解决方案?使用async/await是一个更好的主意和更可接受的方法吗?

This works well however I am wondering if using tasks is the best solution here? Would using async/await be a better idea and more accepted way?

例如，是否应该将控制器标记为异步，并在每次调用服务方法时进行等待?

For example should the controller be marked as async and an await put on each call to the the service methods?

推荐答案

这很好用，但是我想知道使用任务是否是这里最好的解决方案?使用async/await是一个更好的主意和更可接受的方法吗?

This works well however I am wondering if using tasks is the best solution here? Would using async/await be a better idea and more accepted way?

是的，绝对如此.在ASP.NET上执行并行处理会为每个请求消耗多个线程，这可能会严重影响您的可伸缩性.异步处理对于I/O而言要优越得多.

Yes, absolutely. Doing parallel processing on ASP.NET consumes multiple threads per request, which can severely impact your scalability. Asynchronous processing is far superior for I/O.

要使用async，请首先从最低级别的调用开始，在服务内部.可能是在某个时候进行HTTP调用.更改为使用异步HTTP调用(例如HttpClient).然后让async从那里自然生长.

To use async, first start with your lowest-level call, somewhere inside your service. It's probably doing an HTTP call at some point; change that to use asynchronous HTTP calls (e.g., HttpClient). Then let async grow naturally from there.

最终，您将获得异步getdata1Async，getdata2Async和getdata3Async方法，这些方法可以同时使用，例如:

Eventually, you'll end up with asynchronous getdata1Async, getdata2Async, and getdata3Async methods, which can be consumed concurrently as such:

[HttpGet] public async Task<IActionResult> myControllerAction() { var t1 = service.getdata1Async(); var t2 = service.getdata2Async(); var t3 = service.getdata3Async(); await Task.WhenAll(t1, t2, t3); var data = new returnObject { d1 = await t1, d2 = await t2, d3 = await t3 }; return Ok(data); }

使用这种方法，在进行三个服务调用时，myControllerAction使用零线程而不是四个.

With this approach, while the three service calls are in progress, myControllerAction uses zero threads instead of four.