RuntimeError: Event loop is closed (and I don't know why)

Question

我知道，这可能已经被问了一百次了，但我仍然不明白为什么最后总是会出现错误。

import asyncio
import aiohttp

async def read_index_page():
    async with aiohttp.ClientSession() as session:
        async with session.get('https://some/api/url') as resp:
            print(resp.status)

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

    task = loop.create_task(read_index_page())

    await asyncio.gather(task)

if __name__ == '__main__':
    asyncio.run(main())

这报告了众所周知的运行事件外观的时间错误已关闭。我运行这段代码在 Windows 10 机器上。

从我的角度来看，我做的事情是正确的，但我完全是使用 asyncio 的初学者。所以，请温柔一点。 :)

问候，托马斯

Answer 1

尝试为您的应用程序设置另一个循环实现，另一方面我应该说我的 Windows 10 Home 没有错误，在 Python 3.6 上测试（使用 Aiohttp 3.4。 4) 和 Python 3.9。（使用 Aiohttp 3.7.4.post()）

import asyncio
from aiohttp import ClientSession

URL = "http://..."


async def send_req(session: ClientSession):
    async with session.get(URL) as resp:
        if resp.status == 200:
            r = await resp.json()
            print(r)
        else:
            print(resp.status)


async def main():
    # check what loop is really running in our Main Thread now
    loop = asyncio.get_running_loop()
    print(loop)
    # no need to create ClientSession for all send_req, you need only one ClientSession
    async with ClientSession() as session:
        # asyncio gather creates tasks itself, no need to create tasks outside
        await asyncio.gather(*[send_req(session) for _ in range(8)])

if __name__ == '__main__':
    # set another loop implementation:
    asyncio.set_event_loop_policy(asyncio.WindowsSelectorEventLoopPolicy())
    asyncio.run(main())

RuntimeError: Event loop is closed (and I don't know why)

RuntimeError: Event loop is closed (and I don't know why)

python

python-3.x

python-asyncio

aiohttp