[veryactivebot](https://t.me/veryactivebot) backend

veryactive.py

"""
This is the code running the Telegram bot @veryactivebot 
(https://t.me/veryactivebot). It ensure that the bot is 
always doing an action: typing, uploading a document, 
sending audio.. If anyone, for whatever mysterious reason,
finds this code useful, they can use as they want, as long 
as they refer to its source.

In order for the bot to work, its authentification token is 
needed. This token can be specified in an environment 
variable `BOT_TOKEN`.
"""


import logging
import requests
from os import environ
from time import sleep
from pathlib import Path
from random import choice
from threading import Thread

LOGFORMAT = "%(asctime)s\t%(levelname)s:%(funcName)s:%(lineno)s\t%(message)s"
logging.basicConfig(filename="veryactive.log", level=logging.INFO, format=LOGFORMAT)

TOKEN = environ['BOT_TOKEN']

API = lambda m: 'https://api.telegram.org/bot'+TOKEN+'/'+m

ACTIONS = (
	'typing',
	'upload_photo',
	'upload_video',
	'upload_audio',
	'upload_document',
	'find_location',
	'upload_video_note' )

active = set()

last_update = 0

def poll():
	"""
	polls for updates
	"""

	global last_update
	while True:
		logging.info('making poll GET request..')

		params = {
			'allowed_updates': 'message',
			'timeout': 600,
			'offset': last_update+1 }

		req = requests.get(
			API('getUpdates'),
			data=params,
			timeout=(9, 606) )

		req = req.json()

		logging.info(
			f'request returned {req["ok"]}, ' + \
			f'got {len(req["result"])} updates ')

		for u in req['result']:
			try:
				chat_id = u['message']['chat']['id']
				message = u['message']['text']

				if message.startswith('/start'):
					active.add(chat_id)
					params = {'chat_id': chat_id, 'action': choice(ACTIONS) }
					requests.get(API("SendChatAction"), data=params )
					logging.info(f"{chat_id} added to active")

				elif message.startswith('/stop'):
					active.remove(chat_id)
					logging.info(f"{chat_id} removed from active")

			except Exception as e:
				logging.info('an exception happened while processing updates:')
				logging.exception(e)

			finally:
				last_update = u['update_id']


def maintain():
	"""
	reset an action every 5s (expiry timeout)
	"""
	while True:
		Path('iamalive').touch(exist_ok=True)
		logging.info('maintaining the active chats')
		for i in active:
			params = {
				'chat_id': i,
				'action': choice(ACTIONS)
			}

			req = requests.get(
				API("SendChatAction"),
				data=params )

			logging.info(f'{i} refreshed')

		sleep(5)


def main():
	logging.info("starting app..")
	maintainer = Thread(target=maintain)
	maintainer.start()
	logging.info("maintainer thread started")
	logging.info("polling..")
	poll()


if __name__ == '__main__':
	print('running forever')
	while True:
		try:
			main()
		except Exception as e:
			logging.exception(e)