Telegram bots. Downloading files larger than 50mb

Telegram bots allow you to automate many processes. Their use is not limited to one chat, in fact - a bot is just an input-output interface , which in addition to text can also receive and transmit files : images, video, audio, documents ...

• For users, the maximum file size is 1.5GB
• The bots are limited to only 50mb.

How to bypass this restriction - under the cut.

Telegram API

Once users can upload files up to 1.5GB, that means we can - for this we will create an agent (called not to be confused with bots) who will work in conjunction with our Telegram bot. This will require a separate account and Telegram API.

First we go to https://core.telegram.org and register the application according to the instructions, in the end you should get api_id and api_hash
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What does the agent do?

A bot cannot upload files larger than 50mb, but if it has the file_id file already uploaded to the Telegram server, then it can forward it. So the algorithm is as follows

1. An application running on the server through the Bot API generates a file to send
2. Calls the agent to upload the file to Telegram servers
3. Receives from agent file_id
4. Uses the downloaded file.

Code example

The need to download large files appeared when writing @AudioTubeBot - initially the audio file was broken into parts and sent in parts. The functionality of downloading large files was decided to be put into a separate application, which is called via subprocess.check_call

#!/usr/bin/env python3 # -*- coding: utf-8 -*- from telethon import TelegramClient from telethon.tl.types import DocumentAttributeAudio import mimetypes entity = 'AudioTube_bot' #  -    api_id = 1959 api_hash = '88b68d6da53fe68c1c3541bbefc' phone = '+79620181488' client = TelegramClient(entity, api_id, api_hash, update_workers=None, spawn_read_thread=False) client.connect() if not client.is_user_authorized(): # client.send_code_request(phone) #   - ,     FloodWait   client.sign_in(phone, input('Enter code: ')) client.start() def main(argv): file_path = argv[1] file_name = argv[2] chat_id = argv[3] object_id = argv[4] bot_name = argv[5] duration = argv[6] mimetypes.add_type('audio/aac','.aac') mimetypes.add_type('audio/ogg','.ogg') msg = client.send_file( str(bot_name), file_path, caption=str(chat_id + ':' + object_id + ':' + duration), file_name=str(file_name), use_cache=False, part_size_kb=512, attributes=[DocumentAttributeAudio( int(duration), voice=None, title=file_name[:-4], performer='')] ) client.disconnect() return 0 if __name__ == '__main__': import sys main(sys.argv[0:]) 

Comments:

This is the whole code - Telethon library is used here - when launching, the program sends the path to the file to be sent, the file name, chat_id - for whom this file is intended), the name of the bot that called the agent (for example, I have beta and release bots).

client.send_file

Just upload the file to the server via upload , get the file_id and transfer it to the bot - it will not work, the file_id works only inside the chat in which it was created - so that our bot could send the file to the user via file_id - the agent must send this file to him
- then the bot will receive its file_id for this file and will be able to dispose of it.

caption = str (...) - wat ?!

The agent sends files only to the bot, adding a comment to caption — this is for me:

• end user chat_id
• track duration
• object_id in the database to which you want to bind file_id in order not to reload the file (indexing, optimization and all that)

An example of a call in the bot code

The disk in path_file_mp3 has already saved the file to be loaded, call the subroutine and wait for its completion.


In the inbox handler, we do something like this.


Questions / suggestions write in the comments or in the chat .