py3-validate-email/validate_email/domainlist_check.py

82 lines
2.8 KiB
Python

from logging import getLogger
from pathlib import Path
from typing import Optional
from filelock import FileLock
from .email_address import EmailAddress
from .exceptions import DomainBlacklistedError
from .updater import (
BLACKLIST_FILEPATH_INSTALLED, BLACKLIST_FILEPATH_TMP, ENV_IGNORE_UPDATER,
LOCK_PATH, TMP_PATH, update_builtin_blacklist)
SetOrNone = Optional[set]
LOGGER = getLogger(__name__)
class DomainListValidator(object):
'Check the provided email against domain lists.'
domain_whitelist = set()
domain_blacklist = set('localhost')
def __init__(
self, whitelist: SetOrNone = None, blacklist: SetOrNone = None):
if whitelist:
self.domain_whitelist = set(x.lower() for x in whitelist)
if blacklist:
self.domain_blacklist = set(x.lower() for x in blacklist)
else:
self.reload_builtin_blacklist()
@property
def _blacklist_path(self) -> Path:
'Return the path of the `blacklist.txt` that should be loaded.'
try:
# Zero size: file is touched to indicate the preinstalled
# file is still fresh enough
return BLACKLIST_FILEPATH_INSTALLED \
if BLACKLIST_FILEPATH_TMP.stat().st_size == 0 \
else BLACKLIST_FILEPATH_TMP
except FileNotFoundError:
return BLACKLIST_FILEPATH_INSTALLED
def _get_blacklist_lines(self) -> list:
'Return the lines of blacklist.txt as a list.'
bl_path = self._blacklist_path
LOGGER.debug(msg=f'(Re)loading blacklist from {bl_path}')
try:
with open(bl_path) as fd:
return fd.readlines()
except FileNotFoundError:
return []
def reload_builtin_blacklist(self):
'(Re)load our built-in blacklist.'
# Locking is only necessary when we might have an updater
# process running
if ENV_IGNORE_UPDATER:
lines = self._get_blacklist_lines()
else:
TMP_PATH.mkdir(exist_ok=True)
with FileLock(lock_file=str(LOCK_PATH)):
lines = self._get_blacklist_lines()
self.domain_blacklist = set(
x.strip().lower() for x in lines if x.strip())
def __call__(self, email_address: EmailAddress) -> bool:
"""
Check if the email domain is valid, raise
`DomainBlacklistedError` if not.
"""
if email_address.domain in self.domain_whitelist:
return True
if email_address.domain in self.domain_blacklist:
raise DomainBlacklistedError
return True
domainlist_check = DomainListValidator()
# Start an optional update on module load
update_builtin_blacklist(
force=False, background=True,
callback=domainlist_check.reload_builtin_blacklist)