Python asyncio.gather返回None

Question

我正在使用Python asyncio实现一个快速的http客户端。

正如您在worker函数中下面的注释中所看到的，我在完成后立即得到响应。我希望得到的回复是有序的，这就是我使用asyncio.gather的原因。

为什么它返回None？有人能帮上忙吗？

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，因此它隐式返回None。添加return语句，您将得到一个结果

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)