Python用yield from 实现异步协程爬虫

import asyncio
import aiohttp

async def fetch(session, url):
    async with session.get(url) as response:
        return await response.text()

async def crawl(urls):
    async with aiohttp.ClientSession() as session:
        for url in urls:
            html = await fetch(session, url)
            print(html)

if __name__ == '__main__':
    urls = ['https://www.example.com', 'https://www.example.org']
    loop = asyncio.get_event_loop()
    loop.run_until_complete(crawl(urls))