74 lines
2.2 KiB
Python
74 lines
2.2 KiB
Python
import re
|
|
from typing import Optional
|
|
from urllib.parse import urlparse
|
|
|
|
from dns.exception import DNSException
|
|
from dns.resolver import resolve
|
|
|
|
from ._account import AccountConfig
|
|
from ._model import ServerConfig
|
|
|
|
_email_regex = re.compile(r'[^@]+@[^@]+\.[^@]+')
|
|
_from_header_regex = re.compile(r'^(?:"?([^"]+)"?\s+)?<?([^>]+)>?$')
|
|
_ipv4_regex = re.compile(r'^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}$')
|
|
_ipv6_regex = re.compile(r'^[0-9a-fA-F:]+$')
|
|
|
|
|
|
def infer_mail_domain(account: AccountConfig, server: ServerConfig) -> str:
|
|
"""
|
|
Infers the mail domain from the account and server configuration.
|
|
"""
|
|
|
|
if server.domain:
|
|
return server.domain
|
|
|
|
if account.username and _email_regex.match(account.username):
|
|
return account.username.split('@', 1)[1]
|
|
|
|
if server.server:
|
|
if _ipv4_regex.match(server.server) or _ipv6_regex.match(server.server):
|
|
return server.server
|
|
|
|
host = urlparse(server.server).hostname
|
|
assert host, f'Could not parse hostname from server URL: {server.server}'
|
|
host_tokens = host.split('.')
|
|
|
|
while host_tokens:
|
|
try:
|
|
resolve(host, 'MX')
|
|
return host
|
|
except DNSException:
|
|
host_tokens.pop(0)
|
|
host = '.'.join(host_tokens)
|
|
|
|
raise AssertionError(f'Could not resolve MX record for {host}')
|
|
|
|
raise AssertionError('Could not infer mail domain from configuration.')
|
|
|
|
|
|
def infer_mail_address(account: AccountConfig, server: ServerConfig) -> str:
|
|
if account.username and _email_regex.match(account.username):
|
|
return account.username
|
|
|
|
return f'{account.username}@{infer_mail_domain(account, server)}'
|
|
|
|
|
|
def normalize_from_header(
|
|
from_: Optional[str], account: AccountConfig, server: ServerConfig
|
|
) -> str:
|
|
"""
|
|
Normalizes the value of the "From" header.
|
|
"""
|
|
|
|
if not from_:
|
|
from_ = account.display_name or account.username
|
|
|
|
if _email_regex.match(from_):
|
|
return from_
|
|
|
|
m = _from_header_regex.match(from_)
|
|
if m and _email_regex.match(m.group(2)):
|
|
return f'{m.group(1)} <{m.group(2)}>'
|
|
|
|
return f'{from_} <{infer_mail_address(account, server)}>'
|