1"""
 2Email message and email sending related helper functions.
 3"""
 4
 5from __future__ import annotations
 6
 7import socket
 8
 9from plain.utils.encoding import punycode
10
11
12# Cache the hostname, but do it lazily: socket.getfqdn() can take a couple of
13# seconds, which slows down the restart of the server.
14class CachedDnsName:
15    def __str__(self) -> str:
16        return self.get_fqdn()
17
18    def get_fqdn(self) -> str:
19        if not hasattr(self, "_fqdn"):
20            self._fqdn = punycode(socket.getfqdn())
21        return self._fqdn
22
23
24_DNS_NAME = CachedDnsName()