Find all common users in multiple channels

telegram_groups_channels.py

import argparse
from typing import List, Tuple

from telethon import functions, types
from telethon.sync import TelegramClient
from telethon.tl.functions.channels import GetParticipantsRequest


def find_users_in_all_groups(telethon_args: Tuple[str, str, str], channels: List[str]):
    common_users = set()

    with TelegramClient(*telethon_args) as telegram_client:
        for channel in channels:
            channel_users = get_channel_discussion_group_users(telegram_client, channel)

            if len(common_users) == 0:
                common_users.update(channel_users)
            else:
                common_users.intersection_update(channel_users)

    print(f'{len(common_users)} common user(s) found in {len(channels)} channels {channels}:')

    for index, user in enumerate(common_users):
        print(f'[{index}] Username: {user[1]}\n\tName: {user[2]}\n\tTelegram ID: {user[0]}')


def get_channel_discussion_group_users(telegram_client, channel_name):
    channel: types.ChannelFull = telegram_client(functions.channels.GetFullChannelRequest(channel_name))
    channel_users = set()

    for chat in channel.chats:
        if chat.broadcast:
            continue

        for user in telegram_client.iter_participants(chat, filter=types.ChannelParticipantsSearch("")):
            channel_users.add((user.id, user.username, f'{user.first_name} {user.last_name}'))
    
    return channel_users
 

def parse_arguments():
    parser = argparse.ArgumentParser()

    parser.add_argument(
        dest='session_name',
        help='telethon session name'
    )
    parser.add_argument(
        dest='api_id'
    )
    parser.add_argument(
        dest='api_hash'
    )
    parser.add_argument(
        dest='chats',
        nargs='+',
        help='Names of the chats (should)'
    )

    return parser.parse_args()

arguments = parse_arguments()

find_users_in_all_groups(
    (arguments.session_name, arguments.api_id, arguments.api_hash),
    arguments.chats
)