Telegram bot for printer (Linux)

printerbot.py

import os
import pathlib
import logging
import json
from telegram import Update
from telegram.ext import (
    ApplicationBuilder,
    CommandHandler,
    Defaults,
    MessageHandler,
    ContextTypes,
    filters,
)

# This is the Telegram Bot that prints all input documents. It can print pdf and txt files.
# Before sending files for printing user must enter the password by command "/auth <password>".
# This implementation uses "lp -d <printer> <file>" to print files (see function "print_file").
# To adopt this for Windows - extend print_file function with something like https://stackoverflow.com/questions/4498099/silent-printing-of-a-pdf-in-python

# TODO: Set here printer name (Choose one from output of command 'lpstat -p'):
printer_name = "PRINTER_NAME"
# TODO: Set here your bot's token key (from Telegram BotFather)
token_key = "239239239:UNICORNSUNICORNSUNICORNSUNICORNS239"
password = "password"
file_size_limit = 20 * 1024 * 1024
auth_file = "authorized_chats.json"

# Directory where files for printing should be saved
files_dir = "printed_files"
pathlib.Path(files_dir).mkdir(parents=True, exist_ok=True)

# Configuring logging
logging.basicConfig(
    format="%(asctime)s [%(levelname)s] %(message)s",
    level=logging.INFO,
)
# set higher logging level for httpx to avoid all GET and POST requests being logged
logging.getLogger("httpx").setLevel(logging.WARNING)

logger = logging.getLogger(__name__)

authorized_chats = set()


def system_print(file_path):
    os.system(f'lp -d {printer_name} "{file_path}"')


def load_authorized_chats():
    global authorized_chats
    try:
        with open(auth_file, "r") as f:
            authorized_chats = set(json.load(f))
        logger.info("Authorized chats loaded.")
    except FileNotFoundError:
        authorized_chats = set()
        logger.info("No authorized chats file found.")


def save_authorized_chats():
    with open(auth_file, "w") as f:
        json.dump(list(authorized_chats), f)


def auth_passed(update: Update):
    return update.effective_chat.id in authorized_chats


async def start(update: Update, context: ContextTypes.DEFAULT_TYPE):
    logger.info(f"User {update.effective_user.username} started")
    await update.message.reply_text(
        "I'm a printer bot!\n"
        "Authorize with /auth <password> to print files."
    )


async def authorize(update: Update, context: ContextTypes.DEFAULT_TYPE):
    args = ''.join(context.args)

    if auth_passed(update):
        await update.message.reply_text("Already authorized!")
        return

    if password == args:
        authorized_chats.add(update.effective_chat.id)
        save_authorized_chats()
        logger.info(f"{update.effective_user.username} authorized")
        await update.message.reply_text("Authorized successfully!")
    else:
        logger.warning(f"Wrong password from {update.effective_user.username}: {args}")
        await update.message.reply_text("Wrong password!")


async def handle_document(update: Update, context: ContextTypes.DEFAULT_TYPE):
    if not auth_passed(update):
        await update.message.reply_text("Use /auth <password> first.")
        return

    doc = update.message.document
    file_name = doc.file_name
    file_size = doc.file_size

    if file_size > file_size_limit:
        await update.message.reply_text("File too large!")
        return

    await update.message.reply_text("Downloading...")

    file = await context.bot.get_file(doc.file_id)
    file_path = os.path.join(files_dir, file_name)

    logger.info(f"Downloading {file_name}...")
    await file.download_to_drive(file_path)

    logger.info(f"Printing {file_path}...")
    system_print(file_path)

    await update.message.reply_text("Printed!")


def main():
    load_authorized_chats()

    app = ApplicationBuilder().token(token_key).defaults(Defaults(do_quote=True)).build()

    app.add_handler(CommandHandler("start", start))
    app.add_handler(CommandHandler("auth", authorize))
    app.add_handler(MessageHandler(filters.Document.ALL, handle_document))

    logger.info("Bot started...")
    app.run_polling()


if __name__ == "__main__":
    main()

Updated to python-telegram-bot v22.7
Authorized chats are now saved after restart.