Telegram bot on python

Introduction

Once upon a time I had a need to for a telegram bot that will reposts news from external channels to my own channel to stay up-to-day with news from different sources in one place. Doing some short research, I didn’t found suitable open-source script for my needs and I decided to write my own script on python. It is not ideal, but it works :-)

There is a library called Telethon that makes easy to write python applications that can interact with Telegram. Think of it as a wrapper that has already done the heavy job for us, so we can focus on developing an application.

Library Installation

Installation can be done via simple command

pip3 install telethon

Coding

Starting our script with importing library components and creating a client

from telethon import TelegramClient
from telethon import utils
import time
import os, sys

Let’s assign the api id, hash and my phone number

api_id = XXXXXX
api_hash ='xxxxxxxxxxxxxxxxxxxxxxx'
phone_number = '+XXXXXXXXXXX'

To start our client, we have to initialize it

client = TelegramClient('me', api_id, api_hash)
client.start()

And now we have to create a logic that will take the last message from the history and to store it value in a variable. This way we setting variable for a very first time when we are starting the script

for message in client.get_message_history('icodrops', limit=1):
    last = message.id
    print(message.id)

To run our script in a loop, we are adding while operator. Then have another loop that assigning message body to the variable $cryptomessage

while True:

    for message in client.get_message_history('telegram_channel_name', min_id=last): 
        cryptomessage = message.message

With the operator if we are checking if current message id is greater than the first one that was assigned before then we rewriting original variable $last with a current message id.

if message.id > last:
            last = message.id

Next if operator is verifying that message is not empty, as a result we are changing the encoding of the message and sending the message to our telegram channel. Else we are sending a capture of an image that sometimes appears instead of text

if cryptomessage != '':
            mesg1 = cryptomessage.encode('utf-8') 
            client.send_message('cryptoanalizatorfeed', mesg1)
            time.sleep(1)
        else:
            client.send_message('cryptoanalizatorfeed', message.media.caption)

Waiting for the 30 seconds and checking the whole logic again

time.sleep(30)

So, lets see the whole script

#!/usr/bin/python3

from telethon import TelegramClient
from telethon import utils
import time
import os, sys

#My API values
api_id = XXXXXX
api_hash ='xxxxxxxxxxxxxxxxxxxxxxx'
phone_number = '+XXXXXXXXX'

client = TelegramClient('me', api_id, api_hash)
client.start()

for message in client.get_message_history('icodrops', limit=1):
    last = message.id
    print(message.id)

while True:

    for message in client.get_message_history('icodrops', min_id=last): 
        cryptomessage = message.message
        if message.id > last:
            last = message.id
        if cryptomessage != '':
            mesg1 = cryptomessage.encode('utf-8')
            client.send_message('cryptoanalizatorfeed', mesg1)
            time.sleep(1)
        else:
            client.send_message('cryptoanalizatorfeed', message.media.caption)
    time.sleep(30)

This script can be wrapped into a docker image in combination with environment variables for $api_id, $api_hash and $phone_number. In the next article I will show how to wrap such a script into a docker image.