get domains from adblock rules in Python

adblock2domains.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
#

import ipaddress
import re


HEAD = re.compile('^(\|\|?)?(https?://)?')
TAIL = re.compile('(/.*$)|(%2f.*$)|(%2F.*$)')
DOMAIN = re.compile('(\w[-\w]*(\.\w[-\w]*)+)')
WILDCARD = re.compile('^((\w*\*[-\w]*)?(\.))?(\w[-\w]*(\.\w[-\w]*)+)(\*)?')


def isip(s):
    try:
        ipaddress.ip_address(s)
    except ValueError:
        return False
    return True


def adblockfilter(line):
    line = line.strip()
    if not line or line[0] in '![@':
        return False
    elif '/' == line[0] and '/' == line[-1]:
        return False
    return True


def adblock2domains(content):
    it = filter(lambda domain: not isip(domain),
                map(lambda line: WILDCARD.search(line)[4],
                    filter(DOMAIN.search,
                           map(lambda line: TAIL.sub('', line),
                               map(lambda line: HEAD.sub('', line),
                                   filter(adblockfilter,
                                          content.splitlines()))))))
    return set(it)