Python asyncio.gather 返回 None

Question

我正在使用 Python asyncio 来实现快速的 http 客户端。

正如您在工作函数内下面的评论中看到的那样，我会在完成后立即收到回复。我想获得有序的响应，这就是我使用 asyncio.gather 的原因。

为什么它返回 None？有人可以帮忙吗？

非常感谢!

import time
import aiohttp
import asyncio

MAXREQ = 100
MAXTHREAD = 500
URL = 'https://google.com'
g_thread_limit = asyncio.Semaphore(MAXTHREAD)


async def worker(session):
    async with session.get(URL) as response:
        await response.read()   #If I print this line I get the responses correctly

async def run(worker, *argv):
    async with g_thread_limit:
        await worker(*argv)

async def main():
    async with aiohttp.ClientSession() as session:
        await asyncio.gather(*[run(worker, session) for _ in range(MAXREQ)])

if __name__ == '__main__':
    totaltime = time.time()
    print(asyncio.get_event_loop().run_until_complete(main()))   #I'm getting a None here
    print (time.time() - totaltime)

Answer 1

您的函数run不会显式返回任何内容，因此它会隐式返回None。添加return语句即可得到结果

async def worker(session):
    async with session.get(URL) as response:
        return await response.read()


async def run(worker, *argv):
    async with g_thread_limit:
        return await worker(*argv)