telegram-mailgate.py

#!/usr/bin/env python3
#
#   telegram-mailgate is a software to send messages via telegram.
#
#       This file is part of the telegram-mailgate source code.
#
#       telegram-mailgate is free software: you can redistribute it and/or modify
#       it under the terms of the GNU General Public License as published by
#       the Free Software Foundation, either version 3 of the License, or
#       (at your option) any later version.
#
#       telegram-mailgate source code is distributed in the hope that it will be
#   useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
#       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
#       GNU General Public License for more details.
#
#       You should have received a copy of the GNU General Public License
#       along with telegram-mailgate source code. If not,
#   see <http://www.gnu.org/licenses/>.
#

import sys
import logging.config
import argparse
from configparser import ConfigParser
import email
import platform
import telegram
import asyncio

async def main():
    exit_code = 0

    arg_parser = argparse.ArgumentParser()
    arg_parser.add_argument('--config',
                            default='/etc/telegram-mailgate/main.cf',
                            help='use a custom configuration file')
    arg_parser.add_argument('--from',
                            help='overwrite field "From" from the header. '
                                 'Ignored if --raw is specified.')
    arg_parser.add_argument('--queue-id',
                            default=0,
                            help='specify the queue ID of the message for logging')
    arg_parser.add_argument('to',
                            nargs='+',
                            help='the recipients')
    group = arg_parser.add_mutually_exclusive_group()
    group.add_argument('--raw',
                       action='store_true',
                       help='include all sections, header and attachments')
    group.add_argument('--simple-header',
                       action='store_true',
                       help='include a header in a separate message')
    args = arg_parser.parse_args()

    cfg = ConfigParser()
    cfg.read(args.config)

    logging.config.fileConfig(cfg['core']['logging_conf_file'])
    logger = logging.getLogger()

    logger.debug('%s: Reading aliases', args.queue_id)
    aliases = open(cfg['core']['aliases'], encoding='utf8').readlines()
    aliases = dict([x.strip().split(' ') for x in aliases])

    logger.debug('%s: Validating API key', args.queue_id)
    api_key = cfg['api']['key']

    logger.debug('%s: Reading message content', args.queue_id)
    raw_content = sys.stdin.read()
    if args.raw:
        content = raw_content
    else:
        mail = email.message_from_string(raw_content)
        content = mail.get_payload()
    for rcpt in args.to:
        try:
            chat_id = aliases[rcpt]
        except KeyError as e:
            print(e)
            exit_code = 69  # EX_UNAVAILABLE
        logger.info('%s: Sending to %s(%s)', args.queue_id, chat_id, rcpt)

        bot = telegram.Bot(api_key)
        async with bot:
            if args.simple_header:
                sender = getattr(args, 'from') or mail['From']
                msg = 'New mail on {} from {}'.format(platform.node(), sender)
                await bot.send_message(chat_id=chat_id, text=msg)
            await bot.send_message(chat_id=chat_id, text=content)
    
    exit(exit_code)

if __name__ == '__main__':
    asyncio.run(main())