第四章：异步 IO¶

aiohttp¶

安装¶

pip install aiohttp

异步 HTTP 请求¶

import aiohttp
import asyncio

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

async def main():
    html = await fetch('https://example.com')
    print(html)

asyncio.run(main())

并发请求¶

async def fetch_all(urls):
    async with aiohttp.ClientSession() as session:
        tasks = [fetch_one(session, url) for url in urls]
        return await asyncio.gather(*tasks)

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

# 使用
urls = ['https://example.com/1', 'https://example.com/2']
results = asyncio.run(fetch_all(urls))

httpx¶

安装¶

pip install httpx

异步请求¶

import httpx
import asyncio

async def fetch(url):
    async with httpx.AsyncClient() as client:
        response = await client.get(url)
        return response.text

asyncio.run(fetch('https://example.com'))

小结¶

异步 IO 要点：

aiohttp：异步 HTTP 客户端
并发请求：asyncio.gather
httpx：现代 HTTP 客户端

下一章我们将学习异步数据库。