How to send http request through specific network interface?

[ChrisYP]

I have two network interfaces and both with internet access. Let's say my interfaces are eth0 and ETH999. I need specific requests to go through ETH999 interface and eth0 is the default interface in my server.
I can do this with these codes when I use requests.

import socket
import requests
from requests import adapters
from urllib3.poolmanager import PoolManager


class InterfaceAdapter(adapters.HTTPAdapter):

    def __init__(self, **kwargs):
        self.iface = kwargs.pop('iface', None)
        super(InterfaceAdapter, self).__init__(**kwargs)

    def _socket_options(self):
        if self.iface is None:
            return []
        else:
            return [(socket.SOL_SOCKET, socket.SO_BINDTODEVICE, self.iface)]

    def init_poolmanager(self, connections, maxsize, block=False):
        self.poolmanager = PoolManager(
            num_pools=connections,
            maxsize=maxsize,
            block=block,
            socket_options=self._socket_options()
        )


session = requests.Session()
for prefix in ('http://', 'https://'):
    # set ETH999 interface here
    session.mount(prefix, InterfaceAdapter(iface=ETH999'))

print(session.get("https://ifconfig.me/").text

so how to do the same on Httpx? thanks.

[tomchristie]

Hi there. Is this what you're looking for?...

https://www.python-httpx.org/advanced/#custom-transports

For some advanced configuration you might need to instantiate a transport class directly, and pass it to the client instance. One example is the local_address configuration which is only available via this low-level API.

>>> import httpx
>>> transport = httpx.HTTPTransport(local_address="0.0.0.0")
>>> client = httpx.Client(transport=transport)

[ChrisYP]

This doesn't work for me. I have two real physical network cards instead of one card with two IP addresses. I need to specify the second network card for network requests. With your settings, I can only get timeout request errors.

[tomchristie]

Oh okay, looking at this more carefully now, you need to set the socket options, not the local address, right?

What does your # set ETH999 interface here code look like?

[ChrisYP]

import socket
import requests
from requests_toolbelt.adapters.socket_options import SocketOptionsAdapter

session = requests.Session()
# set interface here  -> ETH999 is my interface's name.
options = [(socket.SOL_SOCKET, socket.SO_BINDTODEVICE, b"ETH999")]
for prefix in ('http://', 'https://'):
    session.mount(prefix, SocketOptionsAdapter(socket_options=options))

print(session.get("https://httpbin.org/ip").text)

The above code is work very well for me. Thank you.

[tomchristie]

I've opened an issue for this here... encode/httpcore#662

[tomchristie]

The httpcore package version 0.17.2 now supports this, and I've opened #2715 to add it to httpx.

[karpetrosyan]

Since #2716 has been merged, hopefully this api will provide the answer to your question beginning with version 0.24.2.

>>> import httpx
>>> socket_options = [(socket.SOL_SOCKET, socket.SO_BINDTODEVICE, b"ETH999")]
>>> transport = httpx.HTTPTransport(socket_options=socket_options)
>>> client = httpx.Client(transport=transport)