Question

我想获得一些请求和asyncio的链接。我有一个示例程序，但我认为有一个问题，因为打印函数只在我使用await时被调用。

那么为什么在我调用实际函数的地方不会调用print？我已经理解如果使用await关键字，函数会中断，直到将来可以显示。在我的情况下，应该在await关键字之前调用print函数，因此在print语句之前调用：doing stuff in between或者我错了吗？

import asyncio
import requests
import bs4

urls = ["http://www.google.com", "http://www.google.co.uk"]

async def getContent(url):
    loop = asyncio.get_event_loop()
    print("getting content for: " + url) # print should be called here
    # execute a non async function async
    future = loop.run_in_executor(None, requests.get, url)

    # doing stuff with bs4
    soup = bs4.BeautifulSoup((await future).text, "html.parser") # should now interrupt

    return soup 

async def main():
    loop = asyncio.get_event_loop()

    print("starting gathering...")
    # creating a list of futures
    futures = [getContent(url) for url in urls]
    # packing futures into a awaitable list future
    responses_future = asyncio.gather(*futures)

    print("doing stuff in between...")
    # waiting for all futures
    responses = await responses_future

    print("Done")

    for response in responses:
        print(response)

loop = asyncio.get_event_loop()
loop.run_until_complete(main())

输出：

starting gathering...
doing stuff in between...
getting content for: http://www.google.com
getting content for: http://www.google.co.uk
Done

HTML CODE HERE!

此致

Answer 1

协同程序在等待之前不会被执行，这就是它发生的原因

在python中等待之前，不会在异步函数中调用print函数

1 个答案: