hosts/updateHostsFile.py

#!/usr/bin/env python

# Script by Ben Limmer
# https://github.com/l1m5
#
# This Python script will combine all the host files you provide
# as sources into one, unique host file to keep you internet browsing happy.

# pylint: disable=invalid-name
# pylint: disable=bad-whitespace

from __future__ import (absolute_import, division,
                        print_function, unicode_literals)
from glob import glob

import os
import platform
import re
import shutil
import subprocess
import sys
import tempfile
import time
import fnmatch
import argparse
import socket
import json
import zipfile

# Detecting Python 3 for version-dependent implementations
PY3 = sys.version_info >= (3, 0)

if PY3:
    from urllib.request import urlopen
    raw_input = input
else:  # Python 2
    from urllib2 import urlopen


def get_file_by_url(url):
    try:
        f = urlopen(url)
        return f.read().decode("UTF-8")
    except:
        print("Problem getting file: ", url)


def write_data(f, data):
    if PY3:
        f.write(bytes(data, "UTF-8"))
    else:
        f.write(str(data).encode("UTF-8"))


def list_dir_no_hidden(path):
    # This function doesn't list hidden files
    return glob(os.path.join(path, "*"))


# Project Settings
BASEDIR_PATH = os.path.dirname(os.path.realpath(__file__))

defaults = {
    "numberofrules" : 0,
    "datapath" : os.path.join(BASEDIR_PATH, "data"),
    "freshen" : True,
    "replace" : False,
    "backup" : False,
    "skipstatichosts": False,
    "keepdomaincomments": False,
    "extensionspath" : os.path.join(BASEDIR_PATH, "extensions"),
    "extensions" : [],
    "outputsubfolder" : "",
    "hostfilename" : "hosts",
    "targetip" : "0.0.0.0",
    "ziphosts" : False,
    "sourcedatafilename" : "update.json",
    "sourcesdata": [],
    "readmefilename" : "readme.md",
    "readmetemplate" : os.path.join(BASEDIR_PATH, "readme_template.md"),
    "readmedata" : {},
    "readmedatafilename" : os.path.join(BASEDIR_PATH, "readmeData.json"),
    "exclusionpattern" : "([a-zA-Z\d-]+\.){0,}",
    "exclusionregexs" : [],
    "exclusions" : [],
    "commonexclusions" : ["hulu.com"],
    "blacklistfile" : os.path.join(BASEDIR_PATH, "blacklist"),
    "whitelistfile" : os.path.join(BASEDIR_PATH, "whitelist")}


def main():
    parser = argparse.ArgumentParser(description="Creates a unified hosts file from hosts stored in data subfolders.")
    parser.add_argument("--auto", "-a", dest="auto", default=False, action="store_true", help="Run without prompting.")
    parser.add_argument("--backup", "-b", dest="backup", default=False, action="store_true", help="Backup the hosts files before they are overridden.")
    parser.add_argument("--extensions", "-e", dest="extensions", default=[], nargs="*", help="Host extensions to include in the final hosts file.")
    parser.add_argument("--ip", "-i", dest="targetip", default="0.0.0.0", help="Target IP address. Default is 0.0.0.0.")
    parser.add_argument("--keepdomaincomments", "-k", dest="keepdomaincomments", default=False, help="Keep domain line comments.")
    parser.add_argument("--zip", "-z", dest="ziphosts", default=False, action="store_true", help="Additionally create a zip archive of the hosts file.")
    parser.add_argument("--noupdate", "-n", dest="noupdate", default=False, action="store_true", help="Don't update from host data sources.")
    parser.add_argument("--skipstatichosts", "-s", dest="skipstatichosts", default=False, action="store_true", help="Skip static localhost entries in the final hosts file.")
    parser.add_argument("--output", "-o", dest="outputsubfolder", default="", help="Output subfolder for generated hosts file.")
    parser.add_argument("--replace", "-r", dest="replace", default=False, action="store_true", help="Replace your active hosts file with this new hosts file.")
    parser.add_argument("--flush-dns-cache", "-f", dest="flushdnscache", default=False, action="store_true", help="Attempt to flush DNS cache after replacing the hosts file.")

    global settings

    options = vars(parser.parse_args())

    options["outputpath"] = os.path.join(BASEDIR_PATH,
                                         options["outputsubfolder"])
    options["freshen"] = not options["noupdate"]

    settings = {}
    settings.update(defaults)
    settings.update(options)

    settings["sources"] = list_dir_no_hidden(settings["datapath"])
    settings["extensionsources"] = list_dir_no_hidden(
        settings["extensionspath"])

    # All our extensions folders...
    settings["extensions"] = [os.path.basename(item) for item in
                              list_dir_no_hidden(settings["extensionspath"])]
    # ... intersected with the extensions passed-in as arguments, then sorted.
    settings["extensions"] = sorted(list(
        set(options["extensions"]).intersection(settings["extensions"])))

    with open(settings["readmedatafilename"], "r") as f:
        settings["readmedata"] = json.load(f)

    prompt_for_update()
    prompt_for_exclusions()

    merge_file = create_initial_file()
    remove_old_hosts_file()

    final_file = remove_dups_and_excl(merge_file)
    finalize_file(final_file)

    if settings["ziphosts"]:
        zf = zipfile.ZipFile(os.path.join(settings["outputsubfolder"],
                                          "hosts.zip"), mode='w')
        zf.write(os.path.join(settings["outputsubfolder"], "hosts"),
                 compress_type=zipfile.ZIP_DEFLATED, arcname='hosts')
        zf.close()

    update_readme_data()
    print_success("Success! The hosts file has been saved in folder " +
                  settings["outputsubfolder"] + "\nIt contains " +
                  "{:,}".format(settings["numberofrules"]) +
                  " unique entries.")

    prompt_for_move(final_file)


# Prompt the User
def prompt_for_update():
    # Create hosts file if it doesn't exists
    if not os.path.isfile(os.path.join(BASEDIR_PATH, "hosts")):
        try:
            open(os.path.join(BASEDIR_PATH, "hosts"), "w+").close()
        except:
            print_failure("ERROR: No 'hosts' file in the folder,"
                          "try creating one manually")

    if not settings["freshen"]:
        return

    prompt = "Do you want to update all data sources?"
    if settings["auto"] or query_yes_no(prompt):
        update_all_sources()
    elif not settings["auto"]:
        print("OK, we'll stick with what we've  got locally.")


def prompt_for_exclusions():
    prompt = ("Do you want to exclude any domains?\n"
              "For example, hulu.com video streaming must be able to access "
              "its tracking and ad servers in order to play video.")

    if not settings["auto"]:
        if query_yes_no(prompt):
            display_exclusion_options()
        else:
            print("OK, we'll only exclude domains in the whitelist.")


def prompt_for_flush_dns_cache():
    if settings["flushdnscache"]:
        flush_dns_cache()

    if not settings["auto"]:
        if query_yes_no("Attempt to flush the DNS cache?"):
            flush_dns_cache()


def prompt_for_move(final_file):
    if settings["replace"] and not settings["skipstatichosts"]:
        move_file = True
    elif settings["auto"] or settings["skipstatichosts"]:
        move_file = False
    else:
        prompt = ("Do you want to replace your existing hosts file " +
                  "with the newly generated file?")
        move_file = query_yes_no(prompt)

    if move_file:
        move_hosts_file_into_place(final_file)
        prompt_for_flush_dns_cache()
    else:
        return False
# End Prompt the User


# Exclusion logic
def display_exclusion_options():
    for exclusion_option in settings["commonexclusions"]:
        prompt = "Do you want to exclude the domain " + exclusion_option + " ?"

        if query_yes_no(prompt):
            exclude_domain(exclusion_option)
        else:
            continue

    if query_yes_no("Do you want to exclude any other domains?"):
        gather_custom_exclusions()


def gather_custom_exclusions():
    """
    Gather custom exclusions from the user.
    """

    # We continue running this while-loop until the user
    # says that they have no more domains to exclude.
    while True:
        domain_prompt = ("Enter the domain you want "
                         "to exclude (e.g. facebook.com): ")
        user_domain = raw_input(domain_prompt)

        if is_valid_domain_format(user_domain):
            exclude_domain(user_domain)

        continue_prompt = "Do you have more domains you want to enter?"
        if not query_yes_no(continue_prompt):
            return


def exclude_domain(domain):
    settings["exclusionregexs"].append(re.compile(
        settings["exclusionpattern"] + domain))


def matches_exclusions(stripped_rule):
    stripped_domain = stripped_rule.split()[1]
    for exclusionRegex in settings["exclusionregexs"]:
        if exclusionRegex.search(stripped_domain):
            return True
    return False
# End Exclusion Logic


# Update Logic
def update_all_sources():
    # Update all hosts files regardless of folder depth
    all_sources = recursive_glob("*", settings["sourcedatafilename"])

    for source in all_sources:
        update_file = open(source, "r")
        update_data = json.load(update_file)
        update_url = update_data["url"]
        update_file.close()

        print("Updating source " + os.path.dirname(
            source) + " from " + update_url)

        updated_file = get_file_by_url(update_url)

        try:
            # get rid of carriage-return symbols
            updated_file = updated_file.replace("\r", "")

            hosts_file = open(os.path.join(BASEDIR_PATH,
                                           os.path.dirname(source),
                                           settings["hostfilename"]), "wb")
            write_data(hosts_file, updated_file)
            hosts_file.close()
        except:
            print("Skipping.")
# End Update Logic


# File Logic
def create_initial_file():
    merge_file = tempfile.NamedTemporaryFile()

    # spin the sources for the base file
    for source in recursive_glob(settings["datapath"],
                                 settings["hostfilename"]):
        with open(source, "r") as curFile:
            write_data(merge_file, curFile.read())

    for source in recursive_glob(settings["datapath"],
                                 settings["sourcedatafilename"]):
        update_file = open(source, "r")
        update_data = json.load(update_file)
        settings["sourcesdata"].append(update_data)
        update_file.close()

    # spin the sources for extensions to the base file
    for source in settings["extensions"]:
        for filename in recursive_glob(os.path.join(
                settings["extensionspath"], source), settings["hostfilename"]):
            with open(filename, "r") as curFile:
                write_data(merge_file, curFile.read())

        for update_file_path in recursive_glob(os.path.join(
                settings["extensionspath"], source),
                settings["sourcedatafilename"]):
            update_file = open(update_file_path, "r")
            update_data = json.load(update_file)

            settings["sourcesdata"].append(update_data)
            update_file.close()

    if os.path.isfile(settings["blacklistfile"]):
        with open(settings["blacklistfile"], "r") as curFile:
            write_data(merge_file, curFile.read())

    return merge_file


def remove_dups_and_excl(merge_file):
    number_of_rules = settings["numberofrules"]
    if os.path.isfile(settings["whitelistfile"]):
        with open(settings["whitelistfile"], "r") as ins:
            for line in ins:
                line = line.strip(" \t\n\r")
                if line and not line.startswith("#"):
                    settings["exclusions"].append(line)

    if not os.path.exists(settings["outputpath"]):
        os.makedirs(settings["outputpath"])

    # Another mode is required to read and write the file in Python 3
    final_file = open(os.path.join(settings["outputpath"], "hosts"),
                      "w+b" if PY3 else "w+")

    merge_file.seek(0)  # reset file pointer
    hostnames = {"localhost", "localhost.localdomain",
                 "local", "broadcasthost"}
    exclusions = settings["exclusions"]

    for line in merge_file.readlines():
        write = "true"

        # Explicit encoding
        line = line.decode("UTF-8")

        # replace tabs with space
        line = line.replace("\t+", " ")

        # see gh-271: trim trailing whitespace, periods
        line = line.rstrip(' .') + "\n"

        # Testing the first character doesn't require startswith
        if line[0] == "#" or re.match(r'^\s*$', line[0]):
            write_data(final_file, line)
            continue
        if "::1" in line:
            continue

        stripped_rule = strip_rule(line)  # strip comments
        if not stripped_rule or matches_exclusions(stripped_rule):
            continue

        # Normalize rule
        hostname, normalized_rule = normalize_rule(stripped_rule)
        for exclude in exclusions:
            if exclude in line:
                write = "false"
                break

        if (normalized_rule and (hostname not in hostnames)
                and (write == "true")):
            write_data(final_file, normalized_rule)
            hostnames.add(hostname)
            number_of_rules += 1

    settings["numberofrules"] = number_of_rules
    merge_file.close()

    return final_file


def normalize_rule(rule):
    result = re.search(r'^[ \t]*(\d+\.\d+\.\d+\.\d+)\s+([\w\.-]+)(.*)', rule)
    if result:
        hostname, suffix = result.group(2, 3)

        # Explicitly lowercase and trim the hostname
        hostname = hostname.lower().strip()
        if suffix and settings["keepdomaincomments"]:
            # add suffix as comment only, not as a separate host
            return hostname, "%s %s #%s\n" % (settings["targetip"],
                                              hostname, suffix)
        else:
            return hostname, "%s %s\n" % (settings["targetip"], hostname)
    print("==>%s<==" % rule)
    return None, None


def finalize_file(final_file):
    write_opening_header(final_file)
    final_file.close()


# Some sources put comments around their rules, for accuracy we need
# to strip them the comments are preserved in the output hosts file
def strip_rule(line):
    split_line = line.split()
    if len(split_line) < 2:
        # just return blank
        return ""
    else:
        return split_line[0] + " " + split_line[1]


def write_opening_header(final_file):
    final_file.seek(0)  # reset file pointer
    file_contents = final_file.read()  # save content
    final_file.seek(0)  # write at the top
    write_data(final_file, "# This hosts file is a merged collection "
                           "of hosts from reputable sources,\n")
    write_data(final_file, "# with a dash of crowd sourcing via Github\n#\n")
    write_data(final_file, "# Date: " + time.strftime(
        "%B %d %Y", time.gmtime()) + "\n")
    if settings["extensions"]:
        write_data(final_file, "# Extensions added to this file: " + ", ".join(
            settings["extensions"]) + "\n")
    write_data(final_file, "# Number of unique domains: " + "{:,}\n#\n".format(
        settings["numberofrules"]))
    write_data(final_file, "# Fetch the latest version of this file: "
                           "https://raw.githubusercontent.com/"
                           "StevenBlack/hosts/master/" +
               os.path.join(settings["outputsubfolder"], "") + "hosts\n")
    write_data(final_file, "# Project home page: https://github.com/"
                           "StevenBlack/hosts\n#\n")
    write_data(final_file, "# ==============================="
                           "================================\n")
    write_data(final_file, "\n")

    if not settings["skipstatichosts"]:
        write_data(final_file, "127.0.0.1 localhost\n")
        write_data(final_file, "127.0.0.1 localhost.localdomain\n")
        write_data(final_file, "127.0.0.1 local\n")
        write_data(final_file, "255.255.255.255 broadcasthost\n")
        write_data(final_file, "::1 localhost\n")
        write_data(final_file, "fe80::1%lo0 localhost\n")
        write_data(final_file, "0.0.0.0 0.0.0.0\n")
        if platform.system() == "Linux":
            write_data(final_file, "127.0.1.1 " + socket.gethostname() + "\n")
            write_data(final_file, "127.0.0.53 " + socket.gethostname() + "\n")
        write_data(final_file, "\n")

    preamble = os.path.join(BASEDIR_PATH, "myhosts")
    if os.path.isfile(preamble):
        with open(preamble, "r") as f:
            write_data(final_file, f.read())

    final_file.write(file_contents)


def update_readme_data():
    extensions_key = "base"
    if settings["extensions"]:
        extensions_key = "-".join(settings["extensions"])

    generation_data = {"location": os.path.join(
        settings["outputsubfolder"], ""),
                       "entries": settings["numberofrules"],
                       "sourcesdata": settings["sourcesdata"]}
    settings["readmedata"][extensions_key] = generation_data
    with open(settings["readmedatafilename"], "w") as f:
        json.dump(settings["readmedata"], f)


def move_hosts_file_into_place(final_file):
    """
    Move the newly-created hosts file into its correct location on the OS.

    For UNIX systems, the hosts file is "etc/hosts." On Windows, it's
    "C:\Windows\System32\drivers\etc\hosts."

    For this move to work, you must have administrator privileges to do this.
    On UNIX systems, this means having "sudo" access, and on Windows, it
    means being able to run command prompt in administrator mode.

    Parameters
    ----------
    final_file : file object
        The newly-created hosts file to move.
    """

    filename = os.path.abspath(final_file.name)

    if os.name == "posix":
        print("Moving the file requires administrative privileges. "
              "You might need to enter your password.")
        if subprocess.call(["/usr/bin/sudo", "cp", filename, "/etc/hosts"]):
            print_failure("Moving the file failed.")
    elif os.name == "nt":
        print("Automatically moving the hosts file "
              "in place is not yet supported.")
        print("Please move the generated file to "
              "%SystemRoot%\system32\drivers\etc\hosts")


def flush_dns_cache():
    """
    Flush the DNS cache.
    """

    print("Flushing the DNS cache to utilize new hosts file...")
    print("Flushing the DNS cache requires administrative privileges. " +
          "You might need to enter your password.")

    dns_cache_found = False

    if platform.system() == "Darwin":
        if subprocess.call(["/usr/bin/sudo", "killall",
                            "-HUP", "mDNSResponder"]):
            print_failure("Flushing the DNS cache failed.")
    elif os.name == "nt":
        print("Automatically flushing the DNS cache is not yet supported.")
        print("Please copy and paste the command 'ipconfig /flushdns' in "
              "administrator command prompt after running this script.")
    else:
        if os.path.isfile("/etc/rc.d/init.d/nscd"):
            dns_cache_found = True

            if subprocess.call(["/usr/bin/sudo", "/etc/rc.d/init.d/nscd",
                                "restart"]):
                print_failure("Flushing the DNS cache failed.")
            else:
                print_success("Flushing DNS by restarting nscd succeeded")

        if os.path.isfile("/usr/lib/systemd/system/NetworkManager.service"):
            dns_cache_found = True

            if subprocess.call(["/usr/bin/sudo", "/usr/bin/systemctl",
                                "restart", "NetworkManager.service"]):
                print_failure("Flushing the DNS cache failed.")
            else:
                print_success("Flushing DNS by restarting "
                              "NetworkManager succeeded")

        if os.path.isfile("/usr/lib/systemd/system/wicd.service"):
            dns_cache_found = True

            if subprocess.call(["/usr/bin/sudo", "/usr/bin/systemctl",
                                "restart", "wicd.service"]):
                print_failure("Flushing the DNS cache failed.")
            else:
                print_success("Flushing DNS by restarting wicd succeeded")

        if os.path.isfile("/usr/lib/systemd/system/dnsmasq.service"):
            dns_cache_found = True

            if subprocess.call(["/usr/bin/sudo", "/usr/bin/systemctl",
                                "restart", "dnsmasq.service"]):
                print_failure("Flushing the DNS cache failed.")
            else:
                print_success("Flushing DNS by restarting dnsmasq succeeded")

        if os.path.isfile("/usr/lib/systemd/system/networking.service"):
            dns_cache_found = True

            if subprocess.call(["/usr/bin/sudo", "/usr/bin/systemctl",
                                "restart", "networking.service"]):
                print_failure("Flushing the DNS cache failed.")
            else:
                print_success("Flushing DNS by restarting "
                              "networking.service succeeded")

        if not dns_cache_found:
            print_failure("Unable to determine DNS management tool.")


# Hotfix since merging with an already existing
# hosts file leads to artifacts and duplicates
def remove_old_hosts_file():
    old_file_path = os.path.join(BASEDIR_PATH, "hosts")
    # create if already removed, so remove wont raise an error
    open(old_file_path, "a").close()

    if settings["backup"]:
        backup_file_path = os.path.join(BASEDIR_PATH, "hosts-{}".format(
            time.strftime("%Y-%m-%d-%H-%M-%S")))

        # Make a backup copy, marking the date in which the list was updated
        shutil.copy(old_file_path, backup_file_path)

    os.remove(old_file_path)

    # Create new empty hosts file
    open(old_file_path, "a").close()
# End File Logic


# Helper Functions
def query_yes_no(question, default="yes"):
    """
    Ask a yes/no question via raw_input() and get answer from the user.

    Inspired by the following implementation:

    http://code.activestate.com/recipes/577058

    Parameters
    ----------
    question : str
        The question presented to the user.
    default : str, default "yes"
        The presumed answer if the user just hits <Enter>. It must be "yes",
        "no", or None (means an answer is required of the user).

    Returns
    -------
    yes : Whether or not the user replied yes to the question.
    """

    valid = {"yes": "yes", "y": "yes", "ye": "yes",
             "no": "no", "n": "no"}
    prompt = {None: " [y/n] ",
              "yes": " [Y/n] ",
              "no": " [y/N] "}.get(default, None)

    if not prompt:
        raise ValueError("invalid default answer: '%s'" % default)

    reply = None

    while not reply:
        sys.stdout.write(colorize(question, Colors.PROMPT) + prompt)

        choice = raw_input().lower()
        reply = None

        if default and not choice:
            reply = default
        elif choice in valid:
            reply = valid[choice]
        else:
            print_failure("Please respond with 'yes' or 'no' "
                          "(or 'y' or 'n').\n")

    return reply == "yes"


def is_valid_domain_format(domain):
    if domain == "":
        print("You didn't enter a domain. Try again.")
        return False

    domain_regex = re.compile("www\d{0,3}[.]|https?")

    if domain_regex.match(domain):
        print("The domain " + domain +
              " is not valid. Do not include "
              "www.domain.com or http(s)://domain.com. Try again.")
        return False
    else:
        return True


# A version-independent glob(  ... "/**/" ... )
def recursive_glob(stem, file_pattern):
    if sys.version_info >= (3, 5):
        return glob(stem + "/**/" + file_pattern, recursive=True)
    else:
        if stem == "*":
            stem = "."
        matches = []
        for root, dirnames, filenames in os.walk(stem):
            for filename in fnmatch.filter(filenames, file_pattern):
                matches.append(os.path.join(root, filename))
    return matches


# Colors
class Colors(object):
    PROMPT = "\033[94m"
    SUCCESS = "\033[92m"
    FAIL = "\033[91m"
    ENDC = "\033[0m"


def colorize(text, color):
    return color + text + Colors.ENDC


def print_success(text):
    print(colorize(text, Colors.SUCCESS))


def print_failure(text):
    print(colorize(text, Colors.FAIL))
# End Helper Functions

if __name__ == "__main__":
    main()