一文学会Aiohttp
一、什么是aiohttp库
aiohttp库官网：https://docs.aiohttp.org/en/stable/
aiohttp是一个Python的HTTP客户端/服务器框架，它基于asyncio库实现异步编程模型，可以支持高性能和高并发的HTTP通信。aiohttp用于编写异步的Web服务器、Web应用程序或HTTP客户端，以提供对Web和HTTP资源的访问和操作。
在aiohttp中，HTTP客户端提供了一种发送HTTP请求和处理响应的异步方式，而HTTP服务器则提供了一种异步处理HTTP请求和响应的方式。在使用aiohttp编写Web应用程序时，我们可以选择使用内置的路由器和视图功能来处理HTTP请求，并使用异步模板引擎来渲染HTML页面。
aiohttp支持WebSocket协议，使得我们可以轻松地在应用程序中实现实时通信和数据推送。aiohttp的API设计简单、易用，与Python开发者熟悉的asyncio风格一致。因此，即使没有使用过aiohttp也可以较快上手。 aipyhttp适用于那些需要高性能、高吞吐量、高并发的Python网络应用场景，如实时聊天、在线游戏、大数据分析等。
二、如何安装aiohttp
pip install aiohttp
import aiohttp
async def main():
headers = {'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.3'}
timeout = aiohttp.ClientTimeout(total=10) # 设置总超时时间为10秒
async with aiohttp.ClientSession(headers=headers, timeout=timeout) as session:
async with session.get('https://www.example.com/') as response:
html = await response.text()
print(html)
if __name__ == '__main__':
asyncio.run(main())三、请求和相应
1、post请求
服务器端代码
from aiohttp import web
async def handle(request):
data = await request.post()
name = data.get('name', "Anonymous")
age = data.get('age', "Unknown")
text = f"Hello, {name}, you're {age} years old."
return web.Response(text=text)
app = web.Application()
app.add_routes([web.get('/', handle),
web.post('/', handle)])
if __name__ == '__main__':
web.run_app(app)客户端代码
import aiohttp
import asyncio
async def post_data(session, url):
data = {'name': 'John', 'age': 30}
async with session.post(url, data=data) as response:
return await response.text()
async def main():
async with aiohttp.ClientSession() as session:
html = await post_data(session, 'http://localhost:8080/')
print(html)
loop = asyncio.get_event_loop()
loop.run_until_complete(main())2、get请求
服务器端代码
from aiohttp import web
async def handle(request):
name = request.match_info.get('name', "Anonymous")
text = f"Hello, {name}"
return web.Response(text=text)
app = web.Application()
app.add_routes([web.get('/', handle),
web.get('/{name}', handle)])
if __name__ == '__main__':
web.run_app(app)客户端代码
import aiohttp
import asyncio
async def fetch(session, url):
async with session.get(url) as response:
return await response.text()
async def main():
async with aiohttp.ClientSession() as session:
html = await fetch(session, 'http://localhost:8080/John')
print(html)
loop = asyncio.get_event_loop()
loop.run_until_complete(main())3、获取响应内容
import aiohttp
import asyncio
async def fetch(session, url):
async with session.get(url) as response:
# 获取状态码
status = response.status
# 获取响应头
headers = response.headers
# 以文本形式获取响应正文
text = await response.text()
# 以字节形式获取响应正文
content = await response.read()
return status, headers, text, content
async def main():
async with aiohttp.ClientSession() as session:
status, headers, text, content = await fetch(session, 'https://www.example.com')
print(status)
print(headers)
print(text)
print(content)
loop = asyncio.get_event_loop()
loop.run_until_complete(main())四、Cookies和Session
from aiohttp import web
async def handle(request):
session = await request.session()
count = session.get('count', 0)
count += 1
session['count'] = count
text = f"Visited {count} times."
return web.Response(text=text)
app = web.Application()
app.add_routes([web.get('/', handle)])
if __name__ == '__main__':
web.run_app(app)启用服务起session功能
rom aiohttp import web
async def handle(request):
session = await request.session()
count = session.get('count', 0)
count += 1
session['count'] = count
text = f"Visited {count} times."
return web.Response(text=text)
app = web.Application()
app.add_routes([web.get('/', handle)])
app.cleanup_ctx.append(lambda app: setup_session(app))
async def setup_session(app):
app['session'] = await aiohttp_session.setup(
app, aiohttp_session.SimpleCookieStorage())
if __name__ == '__main__':
web.run_app(app)五、异步处理
1、协程
import aiohttp
import asyncio
async def fetch(session, url):
async with session.get(url) as response:
return await response.text()
async def main():
async with aiohttp.ClientSession() as session:
html = await fetch(session, 'https://www.example.com')
print(html)
loop = asyncio.get_event_loop()
loop.run_until_complete(main())2、回调函数
import aiohttp
import asyncio
def handle_response(response):
print(response.status)
asyncio.get_event_loop().stop()
async def main():
async with aiohttp.ClientSession() as session:
url = 'https://www.example.com'
async with session.get(url) as response:
response.add_done_callback(handle_response)
await asyncio.sleep(1)
loop = asyncio.get_event_loop()
loop.run_until_complete(main())六、SSL认证
1、启动ssl认证
import aiohttp
import asyncio
async def main():
async with aiohttp.ClientSession() as session:
async with session.get('https://www.example.com') as response:
print(await response.text())
loop = asyncio.get_event_loop()
loop.run_until_complete(main())2、使用自签名SSL证书的aiohttp示例
import aiohttp
import asyncio
import ssl
async def main():
ssl_context = ssl.SSLContext(ssl.PROTOCOL_TLS_CLIENT)
ssl_context.load_verify_locations('/path/to/cert.pem')
async with aiohttp.ClientSession() as session:
async with session.get('https://www.example.com', ssl=ssl_context) as response:
print(await response.text())
loop = asyncio.get_event_loop()
loop.run_until_complete(main())七、 WebSockets
WebSocket是一种协议，用于在客户端和服务器之间进行实时双向通信。它允许数据在客户端和服务器之间以全双工方式流动，并且不需要使用HTTP请求/响应周期来发送数据。
WebSocket通过在客户端和服务器之间建立持久连接来实现实时通信。这个连接是基于TCP协议的，但是与HTTP请求/响应不同，它只需要一个握手过程，就可以在客户端和服务器之间创建长期的连接
# 使用aiohttp实现WebSocket
import aiohttp
import asyncio
async def websocket_handler(request):
ws = aiohttp.web.WebSocketResponse()
await ws.prepare(request)
async for msg in ws:
if msg.type == aiohttp.WSMsgType.TEXT:
await ws.send_str('Hello, ' + msg.data)
elif msg.type == aiohttp.WSMsgType.ERROR:
break
return ws
app = aiohttp.web.Application()
app.add_routes([aiohttp.web.get('/', websocket_handler)])
if __name__ == '__main__':
aiohttp.web.run_app(app)