aiohttp服务GET请求返回500错误 loop参数异常修复方案

你遇到的TypeError: BaseEventLoop.create_connection() got an unexpected keyword argument 'loop'是Python版本与旧版asyncio写法不兼容导致的：

Python 3.8 开始就将asyncio系列接口中显式传递loop的参数标记为废弃，到Python 3.10版本正式移除了该参数。你当前运行环境是Python 3.10，代码中多处手动传递loop参数的写法已经不被支持。

除此之外原代码还存在三个隐藏bug：

• asyncio.open_connection本身是协程对象，原代码没有正确处理连接成功后的资源释放，会造成连接泄漏
• 端口扫描区间使用range(begin_port, end_port)是左闭右开区间，传入1-10的参数实际只会扫描1-9端口，和预期不符
• 异常捕获范围不全，仅捕获了TimeoutError，实际端口关闭时会抛出ConnectionRefusedError、OSError等异常，依然会触发500错误

• 删除所有手动获取、传递event loop的冗余代码，Python 3.7+版本asyncio会自动绑定当前运行的事件循环，不需要手动传参
• 修正端口检测逻辑，连接成功后主动关闭writer对象释放资源
• 调整端口遍历的区间范围，将结束端口+1，保证扫描区间和传入参数一致
• 补全异常捕获范围，移除不必要的asyncio.ensure_future冗余包装
• 同步调整pytest用例适配新的代码逻辑

from aiohttp import web
import logging
import json
import asyncio


def catch_exception(func):
    async def decorated_function(ip, port):
        try:
            await func(ip, port)
            return {"port": str(port), "state": "open"}
        except (asyncio.TimeoutError, ConnectionRefusedError, OSError):
            return {"port": str(port), "state": "close"}
    return decorated_function


@catch_exception
async def check_port(ip, port):
    conn = asyncio.open_connection(ip, port)
    reader, writer = await asyncio.wait_for(conn, timeout=3)
    # 连接成功后主动关闭，避免资源泄漏
    writer.close()
    await writer.wait_closed()


async def run(ip, begin_port, end_port):
    tasks = [check_port(ip, p) for p in range(begin_port, end_port + 1)]
    responses = await asyncio.gather(*tasks)
    return responses


async def handle(request):
    ip = request.match_info.get('ip')
    begin_port = int(request.match_info.get('begin_port'))
    end_port = int(request.match_info.get('end_port'))

    results = await run(ip, begin_port, end_port)
    response_obj = {'data': results}

    return web.Response(text=json.dumps(response_obj), status=200, content_type='application/json')


def get_app():
    new_app = web.Application()
    new_app.router.add_get('/scan/{ip}/{begin_port}/{end_port}', handle)
    return new_app


# _________________________ pytest _____________________________________

def create_app():
    test_app = get_app()
    return test_app


async def test_hello(aiohttp_client):
    client = await aiohttp_client(create_app)
    resp = await client.get('/scan/127.0.0.1/1/10')
    assert resp.status == 200
    data = await resp.json()
    assert type(data['data']) is list
    assert len(data['data']) == 10

# _________________________ pytest _____________________________________


logger = logging.getLogger('aiohttp.access')
logger.setLevel(logging.DEBUG)
logger.addHandler(logging.StreamHandler())

if __name__ == '__main__':
    print('Starting!')
    web.run_app(get_app(), host='127.0.0.1', port=8080)

修复后启动服务，访问http://127.0.0.1:8080/scan/127.0.0.1/1/10即可正常返回JSON格式的端口扫描结果，不会再抛出500错误，pytest测试用例也可正常跑通。

内容的提问来源于stack exchange，提问作者Parcurcik