Tourmaline - Telegram Bot Framework For Crystal

Telegram Bot (and hopefully soon Client) API framework for Crystal. Based heavily off of Telegraf this Crystal implementation allows your Telegram bot to be written in a language that's both beautiful and fast. Benchmarks coming soon.

If you want to extend your bot by using NLP, see my other library Cadmium.

Installation
Add this to your application's shard.yml:

dependencies:
   tourmaline:
     github: watzon/tourmaline
     version: ~> 0.7.0

Usage

Basic usage

require "tourmaline/bot"
 
 alias TGBot = Tourmaline::Bot
 
 bot = TGBot::Client.new(ENV["API_KEY"])
 
 bot.command(["start", "help"]) do |message|
   text = "Echo bot is a sample bot created with the Tourmaline bot framework."
   bot.send_message(message.chat.id, text)
 end
 
 bot.command("echo") do |message, params|
   text = params.join(" ")
   bot.send_message(message.chat.id, text)
 end
 
 bot.poll

Listening for events
Tourmaline has a number of events that you can listen for (the same events as Telegraf actually). The full list of events is as can be found in the documentation.

bot.on(:text) do |update|
   text = update.message.not_nil!.text.not_nil!
   puts "TEXT: #{text}"
 end

Adding middleware
Middleware can be created by extending the Tourmaline::Bot::Middleware class. All middleware classes need to have a call(update : Update) method. The middleware will be called on every update.

class MyMiddleware < TGBot::Middleware
 
   # All middlware include a reference to the parent bot.
   # @bot : Tourmaline::Bot::Client
 
   def call(update : Update)
     if message = update.message
       if user = message.from_user
         if text = message.text
           puts "#{user.first_name}: #{text}"
         end
       end
     end
   end
 
 end
 
 bot.use MyMiddleware

Webhooks
Using webhooks is easy, even locally if you use the ngrok.cr package.

# bot.poll
 
 bot.set_webhook("https://example.com/bots/my_tg_bot")
 bot.serve("0.0.0.0", 3400)
 
 # or with ngrok.cr
 
 require "ngrok"
 
 Ngrok.start({ addr: "127.0.0.1:3400" }) do |ngrok|
   bot.set_webhook(ngrok.ngrok_url_https)
   bot.serve("127.0.0.1", 3400)
 end

Payments
You can now accept payments with your Tourmaline app! First make sure you follow the setup instructions here so that your bot is prepared to handle payments. Then just use the send_invoice, answer_shipping_query, and answer_pre_checkout_query methods to send invoices and accept payments.

bot.command("buy") do |message, params|
   bot.send_invoice(
     message.chat.id,
     "Sample Invoice",
     "This is a test...",
     "123344232323",
     "YOUR_PROVIDER_TOKEN",
     "test1",
     "USD",
     bot.labeled_prices([{label: "Sample", amount: 299}, {label: "Another", amount: 369}]).to_json
   )
 end

Games
Ability to create and run games with your Tourmaline Bot is a recent feature that hasn't been tested yet. Please use the issue tracker if you experience problems.

Kemal Middleware
Tourmaline provides middleware for Kemal, just in case you want to use Kemal as the server.

require "kemal"
 require "tourmaline/kemal/tourmaline_handler"
 
 require "./your_bot"
 
 add_handler Kemal::TourmalineHandler.new(
   bot: YourBot.new,
   url: "https://something.com",
   path: "/bot-webhook/#{ENV["TGBOT_API_KEY"]}"
 )
 
 Kemal.run

Note: Telegram won't send webhook requests to non-ssl domains. This means that you need to be running your kemal server with ssl enabled. For local development this can be a pain, but it is made much easier with ngrok.cr.

Development
This currently supports the following features:

Bot API
- Implementation examples
- Easy command syntax
- Robust middleware system
- Standard API queries
- Stickers
- Inline mode
- Long polling
- Webhooks
- Payments
- Games
Client API (in development)