Idiomatic Scala wrapper for the
Telegram Bot API
bot4s.telegram
Simple, extensible, strongly-typed wrapper for the Telegram Bot API.
Table of contents
Installation
Since 6.0.0 telegram-core and telegram-akka are published for Scala 2.12, 2.13 and 3.
Add to your build.sbt file:
// Core with minimal dependencies, enough to spawn your first bot.
libraryDependencies += "com.bot4s" %% "telegram-core" % "6.0.0"
// Extra goodies: Webhooks, support for games, bindings for actors.
libraryDependencies += "com.bot4s" %% "telegram-akka" % "6.0.0"
For mill add to your build.sc project deps:
// Core with minimal dependencies, enough to spawn your first bot.
ivy"com.bot4s::telegram-core:6.0.0",
// Extra goodies: Webhooks, support for games, bindings for actors.
ivy"com.bot4s::telegram-akka:6.0.0"
Quickstart with scala-cli.
Replace BOT_TOKEN with your Telegram bot token.
//> using scala 3.3.6
//> using dep "com.bot4s::telegram-core:6.0.0"
//> using dep "com.softwaremill.sttp.client3::okhttp-backend:3.11.0"
//
import cats.syntax.functor.*
import scala.concurrent.*
import scala.concurrent.duration.*
import com.bot4s.telegram.api.RequestHandler
import com.bot4s.telegram.clients.FutureSttpClient
import com.bot4s.telegram.future.*
import com.bot4s.telegram.methods.SendMessage
import com.bot4s.telegram.models.Message
import sttp.client3.SttpBackend
import sttp.client3.okhttp.OkHttpFutureBackend
/**
* Echo bot.
* Echo, ohcE
*/
class EchoBot(token: String) extends TelegramBot with Polling {
implicit val backend: SttpBackend[Future, Any] = OkHttpFutureBackend()
override val client: RequestHandler[Future] = new FutureSttpClient(token)
override def receiveMessage(msg: Message): Future[Unit] =
msg.text.fold(Future.successful(())) { text =>
request(SendMessage(msg.source, text.reverse)).void
}
}
@main def main() = {
// To run spawn the bot
val bot = new EchoBot("BOT_TOKEN")
val eol: Future[Unit] = bot.run()
println("Press [ENTER] to shutdown the bot, it may take a few seconds...")
scala.io.StdIn.readLine()
bot.shutdown() // initiate shutdown
// Wait for the bot end-of-life
Await.result(eol, Duration.Inf)
}
Examples
class RandomBot(token: String) extends ExampleBot(token) with Polling with Commands[Future] {
val rng = new scala.util.Random(System.currentTimeMillis())
onCommand("coin" or "flip") { implicit msg =>
reply(if (rng.nextBoolean()) "Head!" else "Tail!").void
}
onCommand("real" | "double" | "float") { implicit msg =>
reply(rng.nextDouble().toString).void
}
onCommand("/die" | "roll") { implicit msg =>
reply("⚀⚁⚂⚃⚄⚅" (rng.nextInt(6)).toString).void
}
onCommand("random" or "rnd") { implicit msg =>
withArgs {
case Seq(Int(n)) if n > 0 =>
reply(rng.nextInt(n).toString).void
case _ => reply("Invalid argumentヽ(ಠ_ಠ)ノ").void
}
}
onCommand("choose" | "pick" | "select") { implicit msg =>
withArgs { args =>
replyMd(if (args.isEmpty) "No arguments provided." else args(rng.nextInt(args.size))).void
}
}
onCommand("auto") { implicit msg =>
request(SendDice(msg.chat.id)).void
}
// Extractor
object Int {
def unapply(s: String): Option[Int] = Try(s.toInt).toOption
}
}
/**
* Text-to-speech bot (using Google TTS API)
*
* Google will rightfully block your IP in case of abuse.
* '''Usage:''' /speak Hello World
* '''Inline mode:''' @YourBot This is awesome
*/
class TextToSpeechBot(token: String)
extends ExampleBot(token)
with Polling
with Commands[Future]
with InlineQueries[Future]
with ChatActions[Future] {
def ttsUrl(text: String): String =
s"http://translate.google.com/translate_tts?client=tw-ob&tl=en-us&q=${URLEncoder.encode(text, "UTF-8")}"
onCommand("speak" | "say" | "talk") { implicit msg =>
withArgs { args =>
val text = args.mkString(" ")
for {
r <- Future(scalaj.http.Http(ttsUrl(text)).asBytes)
if r.isSuccess
bytes = r.body
_ <- uploadingAudio // hint the user
voiceMp3 = InputFile("voice.mp3", bytes)
_ <- request(SendVoice(msg.source, voiceMp3))
} yield ()
}
}
def nonEmptyQuery(iq: InlineQuery): Boolean = iq.query.nonEmpty
whenOrElse(onInlineQuery, nonEmptyQuery) { implicit iq =>
answerInlineQuery(
Seq(
// Inline "playable" preview
InlineQueryResultVoice("inline: " + iq.query, ttsUrl(iq.query), iq.query),
// Redirection to /speak command
InlineQueryResultArticle(
"command: " + iq.query,
iq.query,
inputMessageContent = InputTextMessageContent("/speak " + iq.query),
description = "/speak " + iq.query
)
)
).void
} /* empty query */ {
answerInlineQuery(Seq())(_).void
}
}
Calculator bot (using Webhooks) (full example)
class WebhookBot(token: String) extends AkkaExampleBot(token) with Webhook {
val port = 8080
val webhookUrl = "https://88c444ab.ngrok.io"
val baseUrl = "http://api.mathjs.org/v1/?expr="
override def receiveMessage(msg: Message): Future[Unit] =
msg.text.fold(Future.successful(())) { text =>
val url = baseUrl + URLEncoder.encode(text, "UTF-8")
for {
res <- Http().singleRequest(HttpRequest(uri = Uri(url)))
if res.status.isSuccess()
result <- Unmarshal(res).to[String]
_ <- request(SendMessage(msg.source, result))
} yield ()
}
}
Check out the sample bots for more functionality.
Leaking bot tokens
Don't ever expose your bot's token.
Hopefully GitGuardian got you covered and will warn you about exposed API keys.
Webhooks vs. Polling
Both methods are supported.
(Long) Polling is bundled in the core artifact and it's by far the easiest method.
Webhook support comes in the extra artifact based on akka-http; requires a server, it won't work on your laptop.
For a comprehensive reference check Marvin's Patent Pending Guide to All Things Webhook.
Some webhook examples are available here and here (with self signed SSL certificate setup).
Payments
Payments are supported since version 3.0; refer to official payments documentation for details.
I'll support developers willing to integrate and/or improve the payments API; please report issues here.
Games
The Akka extensions include support for games in two flavors; self-hosted (served by the bot itself),
and external, hosted on e.g. GitHub Pages.
Check both the self-hosted and
GitHub-hosted versions of the
popular 2048 game.
Deployment
bot4s.telegram runs on Raspberry Pi, Heroku, Google App Engine and most notably on an old Android (4.1.2) phone with a broken screen via the JDK for ARM.
Bots also runs flawlessly on top of my master thesis: "A meta-circular Java bytecode interpreter for the GraalVM".
Distribution/deployment is outside the scope of the library, but all platforms where Java is
supported should be compatible. You may find sbt-assembly and sbt-docker
very handy.
Scala.js is also supported, bots can run on the browser via the SttpClient. NodeJs is not supported yet.
Running the examples
bot4s.telegram uses mill.
./mill examples.jvm[2.13.10].console
[79/79] examples.jvm[2.13.10].console
Welcome to Scala 2.13.10 (OpenJDK 64-Bit Server VM, Java 11.0.10).
Type in expressions for evaluation. Or try :help.
scala> new RandomBot("BOT_TOKEN").run()
Change RandomBot to whatever bot you find interesting here.
A note on implicits
A few implicits are provided to reduce boilerplate, but are discouraged because unexpected side-effects.
Think seamless T => Option[T] conversion, Markdown string extensions (these are fine)...
Be aware that, for conciseness, most examples need the implicits to compile, be sure to include them.
import com.bot4s.telegram.Implicits._
Versioning
This library uses Semantic Versioning. For the versions available, see the tags on this repository.
Authors
- Alfonso² Peterssen - Owner/maintainer - :octocat: mukel
Looking for maintainers!
See also the list of awesome contributors who participated in this project.
Contributions are very welcome, documentation improvements/corrections, bug reports, even feature requests.
License
This project is licensed under the Apache 2.0 License - see the LICENSE file for details.
Buy Me A Coffee

If you like this library, please consider buying me a coffee. :relaxed: