CRC Bot

About

CRC Bot is a currency converter with built-in calculator and monitoring of exchange rates, which are updated every day via exchange-api. The converter is always active, just send a number or math expression. The result of the expression will be automatically calculated and converted to the final currency.

See running bot: @CRC2_bot

The bot is originally designed to be used when traveling for quick price orientation in stores and quick small calculations. But later I realized that the bot is suitable not only for this purpose and added commands for working with currency pairs, which speeds up the work from the desktop.

Perhaps later I will add a subscription to notifications about currency pair rate changes with the ability to set threshold values.

Features

• Setting the currency pair and rounding mode
• Solving a user-sent mathematical expressions before converting
• Converting a value sent via message or the result of a user-sent math expression
• Sending the exchange rate of the currency pair
• Saving user settings in database (currency pair and rounding mode)

Dependencies

• python-dotenv 1.0.1
• python 3.11.4
• aiogram 3.1.1
• aiosqlite 0.19.0
• aiohttp 3.8.5
• cexprtk 0.4.1

The full list of used libraries is in requirements.txt

pip install -r requirements.txt

Run from sources

To run the bot, you need to specify Telegram Bot API Token — Get token

The get_token.py script allows you to get Telegram Bot API token from .txt file when the bot is running locally or from environment variables when you want to deploy the bot.

Run locally

1. Create an env folder with the "tg_token.txt" file in the directory from which you will run the main.py and add to file your Telegram Bot API token
2. Install all libraries from requirements.txt
3. Run the main script — main.py from src/crc-bot directory

P.S. Bot token and database are hidden in .gitignore

# ignore secret config
bot_token.txt
db.sqlite

Deploy

The project is deployed via Railway. You can use any other cloud service or hosting, but if you want to use Railway, you need to:

1. Set up automatic deployments by specifying the required branch of your project in Railway
2. Specify path to the entry point (main.py) in Railway
3. List all libraries in requirements.txt
4. Specify Python version in runtime.txt
5. Specify your Telegram Bot API in Railway variables

Modules

src/crc-bot

• main.py — the main script that runs a bot polling, a scheduler for updating exchange rates and includes message handlers from all other modules through the router
• menu.py — menu markup generation
• db.py — creating a database and working with it

src/crc-bot/common

• get_token.py — getting Telegram Bot API token from environment variables (for deploy) or .txt files (for local run)
• bot.py — bot instance module
• rates.py — getting all exchange rates via async request to exchangerate-api
• checks.py — methods and variables that are often used in other modules for checking different things
• currencies.py — all currencies supported by exchangerate-api with emoji flags

src/crc-bot/handlers

• round.py — Round menu button handler
• set_currencies.py — From/To menu buttons handler and generation of inline currency buttons
• rate.py — Rate menu button handler
• converter — converter handler, conversion with built-in calculation function

src/crc-bot/commands

• start.py — start command handler
• help.py — help command handler
• about.py — about command handler and inline link-buttons
• curr_commands.py — currency commands (/from /to /pair /swap)