NO_PROXY is not working for IP range/mask

[harochau]

looks like get_environment_proxies is working fine and sets no-proxy correctly, but it is ignored further down the line.
Interestingly, aiohttp shows the same faulty behavior and only requests making the correct requests

import asyncio
import os

import aiohttp

import httpx
from httpx._utils import get_environment_proxies
import requests

os.environ.update({"HTTP_PROXY": "http://192.168.1.2:8000"})  # dummy proxy
os.environ.update({"NO_PROXY": "192.168.0.0/16"})
r = get_environment_proxies()
print(r)  # seems correct

httpx.get('http://192.168.1.2:8001')  # going to proxy
requests.get('http://192.168.1.2:8001')  # NOT going to proxy


async def amain():
    async with aiohttp.ClientSession(trust_env=True) as session:
        async with session.get(url='http://192.168.1.2:8001') as response:  # going to proxy
            print(await response.text())

asyncio.run(amain())

[karpetrosyan]

HTTPX does not support wildcards with ip ranges at all, but we should probably inform the client of this.

[HuM4NoiD]

Can such support be included? requests package supports ip range in the form a.b.0.0/n

[tomchristie]

Points for consideration...

• Could you point to a good resource that neatly describes the IP netmask format?
• In order to have a cohesive API onto this we might consider this from the perspective of the mounts={} API, rather than the NO_PROXY environment variable.
• One way to add support here would be to implement this functionality using a custom transport, that performs the routing. Can you sketch out an implementation of this?

subnet_mask = SubNetMask({
    "*": httpx.HTTPTransport(proxy="http://192.168.1.2:8000"),  # dummy
    "192.168.0.0/16": httpx.HTTPTransport())  # nah
})
client = httpx.Client(transport=subnet_mask)

Related:

• https://www.python-httpx.org/advanced/#mounting-transports
• https://github.com/encode/httpx/pull/2879/files