TelegramBot4s

Idiomatic Scala wrapper for the Telegram Bot API.

The full API is supported: Payments, inline queries, upload files, callbacks, custom markups, games, chat actions... while being strongly-typed, fully asynchronous, and transparently camelCased.

Quick-start

Add to your build.sbt file:

libraryDependencies += "info.mukel" %% "telegrambot4s" % "2.9.5"

Leaking bot tokens

Do not expose tokens unintentionally.

Here's an example that avoids unintentional token sharing:

object SafeBot extends TelegramBot with Polling with Commands {
  // Use 'def' or 'lazy val' for the token, using a plain 'val' may/will
  // lead to initialization order issues.
  // Fetch the token from an environment variable or file.
  lazy val token = scala.util.Properties
    .envOrNone("BOT_TOKEN")
    .getOrElse(Source.fromFile("bot.token").getLines().mkString)

  on("/hello") { implicit msg => _ => reply("My token is SAFE!") }
}

SafeBot.run()

Webhooks vs Polling

Both methods are fully supported. Polling is the easiest method; it can be used locally without any additional requirements. It has been radically improved, doesn't flood the server (like other libraries do) and it's pretty fast.

Using webhooks requires a server (it won't work on your laptop). For a comprehensive reference check Marvin's Patent Pending Guide to All Things Webhook.

Payments

Payments are supported; refer to official payments documetation for details. I'll support developers willing to integrate and/or improve the payments API; please report issues here.

Bonus (or how to turn a spare phone into a Telegram Bot)

Beside the usual ways, I've managed to use the library on a Raspberry Pi 2, and most notably on an old Android (4.1.2) phone with a broken screen. It's also possible to docker-ize a bot.

Contributors

Contributions are highly appreciated, documentation improvements/corrections, idiomatic Scala, bug reports, even feature requests.

• Alexey Alekhin
• Andrey Romanov
• Dmitry Kurinskiy
• ex0ns
• hamidr
• hugemane
• Juan Julián Merelo Guervós
• Kirill Lastovirya
• Maxim Cherkasov
• Onilton Maciel
• Pedro Larroy
• reimai

Usage

Just import info.mukel.telegrambot4s._, api._, methods._, models._, Implicits._ and you are good to go.

Reducing boilerplate

Implicits are provided to reduce boilerplate when dealing with the API; think seamless Option[T] and Either[L,R] conversions. Be aware that most examples need the implicits to compile.

import info.mukel.telegrambot4s.Implicits._

Running the examples

Get into the test console in sbt

sbt
[info] Loading project definition from ./telegrambot4s/project
[info] Set current project to telegrambot4s (in build file:./telegrambot4s/)
> test:console
[info] Compiling 10 Scala sources to ./telegrambot4s/target/scala-2.11/test-classes...
[info] Starting scala interpreter...
[info] 
Welcome to Scala 2.11.8 (Java HotSpot(TM) 64-Bit Server VM, Java 1.8.0_101).
Type in expressions for evaluation. Or try :help.

scala> import info.mukel.telegrambot4s.examples._
import info.mukel.telegrambot4s.examples._

scala> new RandomBot("TOKEN_HERE").run()

Change RandomBot to whatever bot you find interesting here.

Examples

Let me Google that for you!

object LmgtfyBot extends TelegramBot with Polling with Commands {
  def token = "TOKEN"

  on("/lmgtfy") { implicit msg => args =>
    reply(
      "http://lmgtfy.com/?q=" + URLEncoder.encode(args.mkString(" "), "UTF-8"),
      disableWebPagePreview = true
    )
  }
}

LmgtfyBot.run()

Google TTS

object TextToSpeechBot extends TelegramBot with Polling with Commands with ChatActions {
  def token = "TOKEN"
  val ttsApiBase = "http://translate.google.com/translate_tts?ie=UTF-8&client=tw-ob&tl=en-us&q="
  on("/speak") { implicit msg => args =>
    val text = args mkString " "
    val url = ttsApiBase + URLEncoder.encode(text, "UTF-8")
    for {
      response <- Http().singleRequest(HttpRequest(uri = Uri(url)))
      if response.status.isSuccess()
      bytes <-  Unmarshal(response).to[ByteString]
    } /* do */ {
      uploadingAudio // Hint the user
      val voiceMp3 = InputFile("voice.mp3", bytes)
      request(SendVoice(msg.source, voiceMp3))
    }
  }
}

TextToSpeechBot.run()

Using webhooks

object WebhookBot extends TelegramBot with Webhook with Commands {
  def token = "TOKEN"
  override val port = 8443
  override val webhookUrl = "https://ed88ff73.ngrok.io"
  
  import info.mukel.telegrambot4s.Implicits._
  val rng = new Random(System.currentTimeMillis())
  on("/coin", "head or tail") { implicit msg => _ =>
    reply(if (rng.nextBoolean()) "Head!" else "Tail!")
  }
  on("/real", "real number in [0, 1]") { implicit msg => _ =>
    reply(rng.nextDouble().toString)
  }
  on("/die", "classic die [1 .. 6]") { implicit msg => _ =>
    reply((rng.nextInt(6) + 1).toString)
  }
  on("/dice", "throw two classic dice [1 .. 6]") { implicit msg => _ =>
    reply((rng.nextInt(6) + 1) + " " + (rng.nextInt(6) + 1))
  }
  on("/random", "integer in [0, n)") { implicit msg => {
    case Seq(Extractor.Int(n)) if n > 0 =>
      reply(rng.nextInt(n).toString)
    case _ =>
      reply("Invalid argumentヽ(ಠ_ಠ)ノ")
    }
  }
  on("/choose", "randomly picks one of the arguments") {
    implicit msg => args =>
      reply(if (args.isEmpty) "Empty list." else args(rng.nextInt(args.size)))
  }
}

WebhookBot.run()

Custom extensions

It's rather easy to augment your bot with custom DSL-ish shortcuts; e.g. this authenticatedOrElse snippet is taken from the AuthenticationBot example.

  ...
  on("/secret") { implicit msg => _ =>
    authenticatedOrElse {
      admin =>
        reply(
          s"""${admin.firstName}:
             |The answer to life the universe and everything: 42.
             |You can /logout now.""".stripMargin)
    } /* or else */ {
      user =>
        reply(s"${user.firstName}, you must /login first.")
    }
  }

Check out the sample bots for more functionality.