Telegram Bot Creation

Telegram Bot Creation

Full lifecycle for creating and running Telegram bots using python-telegram-bot v20+.

1. Create the Bot

1. Open Telegram, search for @BotFather
2. Send /newbot
3. Choose a display name (e.g. My File Bot)
4. Choose a username ending in bot (e.g. MyFileTransferBot)
5. Save the token — it looks like 7234567890:AAHdqTcvCH1vGWJxfSeOfS...

2. Bot Token Safety

NEVER commit the token to git. Use environment variables:

import os
TOKEN = os.environ["TELEGRAM_BOT_TOKEN"]

Or a .env file (never committed):

TELEGRAM_BOT_TOKEN=7234567890:AAHdqTcv...

3. Minimal Bot (python-telegram-bot v20+)

import asyncio
from telegram import Update
from telegram.ext import Application, CommandHandler, MessageHandler, filters

TOKEN = "YOUR_TOKEN_HERE"

async def start(update: Update, context):
    await update.message.reply_text("Hello! I am active.")

async def echo(update: Update, context):
    await update.message.reply_text(update.message.text)

def main():
    app = Application.builder().token(TOKEN).build()
    app.add_handler(CommandHandler("start", start))
    app.add_handler(MessageHandler(filters.TEXT & ~filters.COMMAND, echo))
    app.run_polling(allowed_updates=Update.ALL_TYPES)

if __name__ == "__main__":
    main()

4. Key Bot Features

5. File Operations

# Receive a file
async def handle_file(update: Update, context):
    file = await update.message.document.get_file()
    await file.download_to_drive("received_file.pdf")
    await update.message.reply_text("File received!")

# Send a file
await update.message.reply_document(
    document=open("report.pdf", "rb"),
    filename="Monthly_Report.pdf",
    caption="Here is your report"
)

6. Deployment

# Install deps
pip install python-telegram-bot

# Run (polling mode — simple, no webhook needed)
python bot.py

# Or use systemd / Docker for production

7. Common Pitfalls

• Token exposed — revoke immediately: BotFather → /mybots → select bot → API Token → Revoke
• Handler order matters — add CommandHandler before MessageHandler or commands get caught as text
• Conversations — use ConversationHandler for multi-step flows
• Rate limits — Telegram enforces ~30 messages/second per chat