How can I download the chat history of a group in Telegram?

Question

I would like to download the chat history (all messages) that were posted in a public group on Telegram. How can I do this with python?

I've found this method in the API https://core.telegram.org/method/messages.getHistory which I think looks like what I'm trying to do. But how do I actually call it? It seems there's no python examples for the MTproto protocol they use.

I also looked at the Bot API, but it doesn't seem to have a method to download messages.

Answer 1

You can use Telethon. Telegram API is fairly complicated and with the telethon, you can start using telegram API in a very short time without any pre-knowledge about the API.

pip install telethon

Then register your app (taken from telethon):

the link is: https://my.telegram.org/

Then to obtain message history of a group (assuming you have the group id):

chat_id = YOUR_CHAT_ID
api_id=YOUR_API_ID
api_hash = 'YOUR_API_HASH'

from telethon import TelegramClient
from telethon.tl.types.input_peer_chat import InputPeerChat

client = TelegramClient('session_id', api_id=api_id, api_hash=api_hash)
client.connect()
chat = InputPeerChat(chat_id)

total_count, messages, senders = client.get_message_history(
                        chat, limit=10)

for msg in reversed(messages):
    # Format the message content
    if getattr(msg, 'media', None):
        content = '<{}> {}'.format(  # The media may or may not have a caption
        msg.media.__class__.__name__,
        getattr(msg.media, 'caption', ''))
    elif hasattr(msg, 'message'):
        content = msg.message
    elif hasattr(msg, 'action'):
        content = str(msg.action)
    else:
        # Unknown message, simply print its class name
        content = msg.__class__.__name__

    text = '[{}:{}] (ID={}) {}: {} type: {}'.format(
            msg.date.hour, msg.date.minute, msg.id, "no name",
            content)
    print (text)

The example is taken and simplified from telethon example.