use go-transproxy with FreeBSD, macOS

transproxy-helper.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-
 
import argparse
import ipaddress
import itertools
import subprocess
import tempfile
import os
import signal
 
def _main():
    parser = argparse.ArgumentParser(description="Transproxy Helper")
    parser.add_argument('proxy', help="Proxy URL (HTTP, HTTPS)")
    parser.add_argument('no_proxy_address', default="10.0.0.0/8,172.16.0.0/12,192.168.0.0/16,169.254.0.0/16,100.64.0.0/10", help="", nargs="?")
    parser.add_argument('--default-pf', default='/etc/pf.conf')
    parser.add_argument('--transproxy-options', default=["-disable-iptables"], nargs="*")
    options = parser.parse_args()

    ipnetwork = [ipaddress.ip_network("0.0.0.0/0")]

    for one in options.no_proxy_address.split(','):
        #print(one.strip(), ipnetwork)
        one_network = ipaddress.ip_network(one.strip())
        new_networks = [x.address_exclude(one_network) if x.overlaps(one_network) else [x] for x in ipnetwork]
        ipnetwork = list(itertools.chain(*new_networks))

    with tempfile.NamedTemporaryFile(mode="w+", prefix="pf-", suffix=".conf", encoding='utf-8') as tmp:
        print('''Packets = "proto tcp from em0 to {''' + ", ".join([str(x) for x in ipnetwork]) + '''}"
rdr pass log on lo0 $Packets port 80 -> 127.0.0.1 port 3129
rdr pass log on lo0 $Packets port 443 -> 127.0.0.1 port 3130
pass out on em0 route-to lo0 inet $Packets port {80, 443} keep state''', file=tmp)
        tmp.flush()
        print(tmp.name)

        print("Enabling firewall settings")
        subprocess.run(["sudo", "pfctl", "-f", tmp.name])

        env = dict(os.environ)
        env['no_proxy'] = options.no_proxy_address
        env['http_proxy'] = options.proxy
        env['https_proxy'] = options.proxy

        try:
            p = subprocess.run(["./transproxy"] + options.transproxy_options, env=env)
        except KeyboardInterrupt:
            pass

        print("Clearing firewall settings")
        subprocess.run(["sudo", "pfctl", "-f", options.default_pf])
    
 
if __name__ == '__main__':
    _main()