Code for How to Make a Telegram Bot in Python Tutorial

telegram_bot.py

import telegram
import telegram.ext
import re
from random import randint

# The API Key we received for our bot
API_KEY = "<INSERT_API_KEY_HERE>"
# Create an updater object with our API Key
updater = telegram.ext.Updater(API_KEY)
# Retrieve the dispatcher, which will be used to add handlers
dispatcher = updater.dispatcher
# Our states, as integers
WELCOME = 0
QUESTION = 1
CANCEL = 2
CORRECT = 3

# The entry function
def start(update_obj, context):
    # send the question, and show the keyboard markup (suggested answers)
    update_obj.message.reply_text("Hello there, do you want to answer a question? (Yes/No)",
        reply_markup=telegram.ReplyKeyboardMarkup([['Yes', 'No']], one_time_keyboard=True)
    )
    # go to the WELCOME state
    return WELCOME

# helper function, generates new numbers and sends the question
def randomize_numbers(update_obj, context):
    # store the numbers in the context
    context.user_data['rand_x'], context.user_data['rand_y'] = randint(0,1000), randint(0, 1000)
    # send the question
    update_obj.message.reply_text(f"Calculate {context.user_data['rand_x']}+{context.user_data['rand_y']}")

# in the WELCOME state, check if the user wants to answer a question
def welcome(update_obj, context):
    if update_obj.message.text.lower() in ['yes', 'y']:
        # send question, and go to the QUESTION state
        randomize_numbers(update_obj, context)
        return QUESTION
    else:
        # go to the CANCEL state
        return CANCEL

# in the QUESTION state
def question(update_obj, context):
    # expected solution
    solution = int(context.user_data['rand_x']) + int(context.user_data['rand_y'])
    # check if the solution was correct
    if solution == int(update_obj.message.text):
        # correct answer, ask the user if he found tutorial helpful, and go to the CORRECT state
        update_obj.message.reply_text("Correct answer!")
        update_obj.message.reply_text("Was this tutorial helpful to you?")
        return CORRECT
    else:
        # wrong answer, reply, send a new question, and loop on the QUESTION state
        update_obj.message.reply_text("Wrong answer :'(")
        # send another random numbers calculation
        randomize_numbers(update_obj, context)
        return QUESTION

# in the CORRECT state
def correct(update_obj, context):
    if update_obj.message.text.lower() in ['yes', 'y']:
        update_obj.message.reply_text("Glad it was useful! ^^")
    else:
        update_obj.message.reply_text("You must be a programming wizard already!")
    # get the user's first name
    first_name = update_obj.message.from_user['first_name']
    update_obj.message.reply_text(f"See you {first_name}!, bye")
    return telegram.ext.ConversationHandler.END

def cancel(update_obj, context):
    # get the user's first name
    first_name = update_obj.message.from_user['first_name']
    update_obj.message.reply_text(
        f"Okay, no question for you then, take care, {first_name}!", reply_markup=telegram.ReplyKeyboardRemove()
    )
    return telegram.ext.ConversationHandler.END

# a regular expression that matches yes or no
yes_no_regex = re.compile(r'^(yes|no|y|n)$', re.IGNORECASE)
# Create our ConversationHandler, with only one state
handler = telegram.ext.ConversationHandler(
      entry_points=[telegram.ext.CommandHandler('start', start)],
      states={
            WELCOME: [telegram.ext.MessageHandler(telegram.ext.Filters.regex(yes_no_regex), welcome)],
            QUESTION: [telegram.ext.MessageHandler(telegram.ext.Filters.regex(r'^\d+$'), question)],
            CANCEL: [telegram.ext.MessageHandler(telegram.ext.Filters.regex(yes_no_regex), cancel)],
            CORRECT: [telegram.ext.MessageHandler(telegram.ext.Filters.regex(yes_no_regex), correct)],
      },
      fallbacks=[telegram.ext.CommandHandler('cancel', cancel)],
      )
# add the handler to the dispatcher
dispatcher.add_handler(handler)
# start polling for updates from Telegram
updater.start_polling()
# block until a signal (like one sent by CTRL+C) is sent
updater.idle()