协程

1.背景

2.python 异步IO库介绍：asyncio

import asyncio
import aiohttp
from main import timethis
urls = [
    f'https://www.cnblogs.com/sitehome/p/{page}'
    for page in range(1,10)
]
async def async_craw(url):
    print('start craw url',url)
    async with aiohttp.ClientSession() as session:
        async with session.get(url) as resp:
            result = await resp.text()
            print(f'end craw url:{url},{len(result)}')
loop = asyncio.get_event_loop()
tasks = [
    loop.create_task(async_craw(url))
    for url in urls
]
@timethis
def do_main():
    loop.run_until_complete(asyncio.wait(tasks))
if __name__ == '__main__':
    do_main()