aiohttp 是 Python 异步编程最常用的一个 web 请求库了, 依托于 asyncio, 性能非常吓人. 下面列举几个常见的用法:

# 最基础: 并发下载网页

“`
import aiohttp
import asyncio

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

async def main():
urls = [
‘http://python.org’,
‘https://google.com’,
‘http://yifei.me’
]
tasks = []
async with aiohttp.ClientSession() as session:
for url in urls:
tasks.append(fetch(session, url))
htmls = await asyncio.gather(*tasks)
for html in htmls:
print(html[:100])

if __name__ == ‘__main__’:
loop = asyncio.get_event_loop()
loop.run_until_complete(main())
“`