如何在龙卷风中使用 Asynchttp [英] how to use Asynchttp in tornado

问题描述

AsynceHTTPClient 不是非阻塞客户端吗?

AsynceHTTPClient isn't a non-blocking client?

当我使用请求获得响应时，它的工作.但是当我使用 AsyncTTTPClient 发布请求时，它不起作用.

when i use requests to get response,its work.but i when i use AsyncTTTPClient to post a request,its doesn't work.

async def go():
    print('go---------------')
    client = AsyncHTTPClient()
    request = HTTPRequest(url='http://127.0.0.1:8001/api', 
method='GET',)
    r = await client.fetch(request)
    print(r.code, r.body)

async def m(r):
    for _ in range(r):
        await go()

loop = asyncio.get_event_loop()
loop.run_until_complete(m(100))

当我使用 AsyncHTTPClient 时，我认为结果就像这个内容

when i use AsyncHTTPClient i think the result is like this content

去---去---去---去---......

go--- go--- go--- go--- ......

但真正的结果是

go--- 200 b'' go--- 200 b'' ......

go--- 200 b'' go--- 200 b'' .......

我想要一个非阻塞请求，所以它可以先发送所有 100 个请求，然后再接收响应，但我在每次响应后都得到了每个响应.它不是非阻塞模式我的代码有问题吗?我该怎么办?

i want a non-blocking requests,so it may send all 100 requests first,and recive the response later, but i got the each response after each reponse .itsn't not-blocking mode is there something wrong with my code? what should i do?

推荐答案

您所看到的是在这种情况下使用协程的缺点.因为即使请求是非阻塞的，它们也不是真正的异步.

What you're seeing is a disadvantage of using coroutines in this case. Because even though the requests are non-blocking, they are not really asynchronous.

您可以使用 gen.Waiterator一次发送所有请求，真正异步.

You can use gen.WaitIterator to send all the requests at once, truly asynchronously.

正如文档所说:

如果你需要尽快得到每个future的结果，或者如果你需要一些future的结果即使其他一些产生错误，你可以使用WaitIterator.

If you need to get the result of each future as soon as possible, or if you need the result of some futures even if others produce errors, you can use WaitIterator.

它非常适合您的用例.

gen.WaitIterator 将任意数量的期货作为参数，并在期货完成时产生期货.

gen.WaitIterator takes an arbitrary number of futures as arguments and yields the futures as they finish.

但是，要使其工作，您需要将 for 循环移动到 go 协程内.示例:

However, for this to work, you;ll need to move your for loop inside the go coroutine. Example:

from tornado import gen

async def go(r):
    client = AsyncHTTPClient()
    futures = []

    for _ in range(r):
        print('go----------')
        request = HTTPRequest(url='http://127.0.0.1:8001/api', method='GET',)
        futures.append(client.fetch(request))

    async for result in gen.WaitIterator(*futures):
        print(result.code, result.body)

<小时>

作为旁注，还有另一种方法可以实现这一点——使用回调.但是，WaitIterator 应该优先于回调.我写了一篇博客文章 关于这个，如果你有兴趣的话.

---

As a side note, there's another way to accomplish this—using callbacks. However, WaitIterator should be preferred over callbacks. I wrote a blog post about this sometime ago, if you're interested.

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