Fake SMTP server in Python that saves received email in TMP folder and opens them right away

fake_smtp_server.py

import argparse
import asyncore
import logging
import os
import platform
import smtpd
import subprocess
import tempfile
from datetime import datetime

logging.basicConfig(level=logging.INFO, format='%(asctime)s - %(name)s - %(levelname)s - %(message)s')

parser = argparse.ArgumentParser()
parser.add_argument('--open', action='store_true', help='Automatically open email with default email program')
args = parser.parse_args()
args.open = True


class FakeSMTPServer(smtpd.SMTPServer):
    def __init__(self, localaddr, remoteaddr):
        super().__init__(localaddr, remoteaddr)
        logging.info(f'Starting fake SMTP server on {localaddr[0]}:{localaddr[1]}')

    def process_message(self, peer, mailfrom, rcpttos, data, mail_options=None, rcpt_options=None):
        temp_dir = tempfile.gettempdir()
        date_time = datetime.now().strftime('%Y%m%d%H%M%S')
        file_name = os.path.join(temp_dir, f'email_{date_time}.msg')
        with open(file_name, 'wb') as f:
            f.write(data)
        logging.info(f'Saved email from {mailfrom} to {rcpttos} to: {file_name}')
        if args.open:
            if platform.system() == 'Linux':
                subprocess.call(['xdg-open', file_name])
            elif platform.system() == 'Darwin':
                subprocess.call(['open', file_name])
            elif platform.system() == 'Windows':
                subprocess.call(['start', file_name], shell=True)


server = FakeSMTPServer(('127.0.0.1', 1025), None)
asyncore.loop()