aiohttp.client_exceptions.ClientConnectorError: 无法连接到主机 stackoverflow.com:443 ssl:default [连接调用失败 ('151.101.193.69', 443)]

Question

这是我的代码：

import asyncio
from aiohttp import ClientSession


async def main():
    url = "https://stackoverflow.com/"

    async with ClientSession() as session:
        async with session.get(url) as resp:
            print(resp.status)

asyncio.run(main())

如果我在我的电脑上运行它，一切正常，但如果我在 pythonanywhere 上运行它，我会收到这个错误：

Traceback (most recent call last):
  File "/home/0dminnimda/.local/lib/python3.8/site-packages/aiohttp/connector.py", line 936, in _wrap_create_connection
    return await self._loop.create_connection(*args, **kwargs)  # type: ignore  # noqa
  File "/usr/lib/python3.8/asyncio/base_events.py", line 1017, in create_connection
    raise exceptions[0]
  File "/usr/lib/python3.8/asyncio/base_events.py", line 1002, in create_connection
    sock = await self._connect_sock(
  File "/usr/lib/python3.8/asyncio/base_events.py", line 916, in _connect_sock
    await self.sock_connect(sock, address)
  File "/usr/lib/python3.8/asyncio/selector_events.py", line 485, in sock_connect
    return await fut
  File "/usr/lib/python3.8/asyncio/selector_events.py", line 517, in _sock_connect_cb
    raise OSError(err, f'Connect call failed {address}')
ConnectionRefusedError: [Errno 111] Connect call failed ('151.101.193.69', 443)
The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "test_c.py", line 39, in <module>
    asyncio.run(main())
  File "/usr/lib/python3.8/asyncio/runners.py", line 43, in run
    return loop.run_until_complete(main)
  File "/usr/lib/python3.8/asyncio/base_events.py", line 608, in run_until_complete
    return future.result()
  File "test_c.py", line 28, in main
    async with session.get(url, timeout=30) as resp:  # , headers=headers
  File "/home/0dminnimda/.local/lib/python3.8/site-packages/aiohttp/client.py", line 1012, in __aenter__
    self._resp = await self._coro
  File "/home/0dminnimda/.local/lib/python3.8/site-packages/aiohttp/client.py", line 480, in _request
    conn = await self._connector.connect(
  File "/home/0dminnimda/.local/lib/python3.8/site-packages/aiohttp/connector.py", line 523, in connect
    proto = await self._create_connection(req, traces, timeout)
  File "/home/0dminnimda/.local/lib/python3.8/site-packages/aiohttp/connector.py", line 858, in _create_connection
    _, proto = await self._create_direct_connection(
  File "/home/0dminnimda/.local/lib/python3.8/site-packages/aiohttp/connector.py", line 1004, in _create_direct_connection
    raise last_exc
  File "/home/0dminnimda/.local/lib/python3.8/site-packages/aiohttp/connector.py", line 980, in _create_direct_connection
    transp, proto = await self._wrap_create_connection(
  File "/home/0dminnimda/.local/lib/python3.8/site-packages/aiohttp/connector.py", line 943, in _wrap_create_connection
    raise client_error(req.connection_key, exc) from exc
aiohttp.client_exceptions.ClientConnectorError: Cannot connect to host stackoverflow.com:443 ssl:default [Connect call failed ('151.101.193.69', 443)]
Unclosed client session
client_session: <aiohttp.client.ClientSession object at 0x7f25a71d1a90>

1 - 主机上的 aiohttp，2 - 我的电脑上的 aiohttp

Name: aiohttp
Version: 3.6.2
Summary: Async http client/server framework (asyncio)
Home-page: https://github.com/aio-libs/aiohttp
Author: Nikolay Kim
Author-email: fafhrd91@gmail.com
License: Apache 2
Location: /home/0dminnimda/.local/lib/python3.8/site-packages
Requires: chardet, async-timeout, multidict, yarl, attrs
Required-by: 

Name: aiohttp
Version: 3.6.2
Summary: Async http client/server framework (asyncio)
Home-page: https://github.com/aio-libs/aiohttp
Author: Nikolay Kim
Author-email: fafhrd91@gmail.com
License: Apache 2
Location: c:\users\asus\appdata\roaming\python\python38\site-packages
Requires: async-timeout, attrs, chardet, yarl, multidict
Required-by: 

我很茫然，不是这样吗？我正在使用 python3.8 运行这两个文件。

我也试过其他网址，他们有同样的问题

我需要添加更多细节吗？

Answer 1

如果您使用的是带有python（3.8 或更高版本）和aiohttp（3.7.4 或更旧版本）的Windows 操作系统 ，有时出现以下异常的解决方案是：
... Cannot connect to host <REQUESTED URL>:443 ssl:default [The parameter is incorrect]

import sys

...

policy = asyncio.WindowsSelectorEventLoopPolicy()
asyncio.set_event_loop_policy(policy)

asyncio.run(main())

你可以检查你的Python版本和操作系统：

import sys

...

if (sys.platform.startswith('win')
        and sys.version_info[0] == 3
        and sys.version_info[1] >= 8):
    policy = asyncio.WindowsSelectorEventLoopPolicy()
    asyncio.set_event_loop_policy(policy)

asyncio.run(main())

在这里，在第 4536 期中，所有内容都有更详细的描述。

Answer 2

第一个解决方案

参考论坛的帮助，我trust_env = True在创建客户端时添加，现在一切正常。

说明：PythonAnywhere 上的免费帐户必须使用代理才能连接到公共互联网，但默认情况下 aiohttp 不会连接到可从环境变量访问的代理。

链接到 aiohttp 文档（查找名为“trust_env”的参数）

这是新代码：

import asyncio
from aiohttp import ClientSession


async def main():
    url = "https://stackoverflow.com/"

    async with ClientSession(trust_env=True) as session:
        async with session.get(url) as resp:
            print(resp.status)

asyncio.run(main())

如果第一个没有帮助你的解决方案

您尝试访问的域必须在白名单中，否则您也可能会收到此错误。

在这种情况下，您需要在 pythonanywhere 论坛上发布一个新主题，要求将域添加到白名单。
如果这是一个 api，那么您需要提供一个指向该 api 文档的链接。