# How to make a simple telegram bot on python

It's very simple to make a telegram bot using python. Let's try and make a simple bot - it has only one supported command `/cat` (to get random cat pictures) apart from the default `/start` and `/help`.

Requirements - 
1. Python3 installed
2. pip3 installed

### Install the requirements
```
pip3 install python-telegram-bot --upgrade
pip3 install requests
```

## Let's start

We will need to make a `main.py` file, below is a scaffold which we will need for almost any bot - 

```python
import logging
from telegram.ext import Updater, CommandHandler, MessageHandler, Filters

logging.basicConfig(format='%(asctime)s - %(name)s - %(levelname)s - %(message)s',
                    level=logging.INFO)
logger = logging.getLogger(__name__)

def start(update, context):
    update.message.reply_text('Hi use /cat to get cat pics!')


def help_command(update, context):
    update.message.reply_text('Help: use /cat to get cat pics!')


if __name__ == '__main__':
    TOKEN = "<the bot token>"
    updater = Updater(TOKEN, use_context=True)

    # Get the dispatcher to register handlers
    dp = updater.dispatcher

    # on different commands - answer in Telegram
    dp.add_handler(CommandHandler("start", start))
    dp.add_handler(CommandHandler("help", help_command))

    # Start the Bot
    updater.start_polling()

    # Run the bot until you press Ctrl-C
    updater.idle()
```

In the above code, we need to add a new handler inside `__main__`
```python
dp.add_handler(CommandHandler("cat", catpic))
```
Now, we need to define the `catpic` handler method
```python
def catpic(update, context):
    import requests
    url = requests.get('https://api.thecatapi.com/v1/images/search').json()[0]["url"]
    update.message.reply_photo(url)
    update.message.reply_text("Here is a nice cat!")
```
We get a image url from the API and use the reply_photo method to send that image link. 

## Create a bot on telegram

1. Goto [t.me/botfather](https://t.me/botfather), this is a bot by telegram which helps us create  and manage our bots.
2. write `/start` to see a list of all commands
3. write `/newbot` to start creation of a new bot
4. follow the steps and get the token after the bot is created
5. in the main.py update the `TOKEN` variable with the new bot token

## Run the bot
```bash
python3 main.py
```
Goto your bot on telegram and try the commands - 
1. `/start`
2. `/help`
3. `/cat`

`/cat` command should give you a nice picture of a cat.