teloxide/README.md

teloxide

A full-featured framework that empowers you to easily build Telegram bots using the async/.await syntax in Rust. It handles all the difficult stuff so you can focus only on your business logic.

Features

• Type-safe. teloxide leverages the Rust's type system with two serious implications: resistance to human mistakes and tight integration with IDEs. Write fast, avoid debugging as possible.

Getting started

1. Create a new bot using @Botfather to get a token in the format 123456789:blablabla.
2. Initialise the TELOXIDE_TOKEN environmental variable to your token:

$ export TELOXIDE_TOKEN=MyAwesomeToken

3. Be sure that you are up to date:

$ rustup update stable

4. Execute cargo new my_bot, enter the directory and put these lines into your Cargo.toml:

[dependencies]
teloxide = "0.1.0"
log = "0.4.8"
tokio = "0.2.11"
pretty_env_logger = "0.4.0"

The ping-pong bot

This bot has a single message handler, which answers "pong" to each incoming message:

(Full)

use teloxide::prelude::*;

#[tokio::main]
async fn main() {
    teloxide::enable_logging!();
    log::info!("Starting the ping-pong bot!");

    let bot = Bot::from_env();

    Dispatcher::<RequestError>::new(bot)
        .message_handler(&|ctx: DispatcherHandlerCtx<Message>| async move {
            ctx.answer("pong").send().await?;
            Ok(())
        })
        .dispatch()
        .await;
}

Commands

Commands are defined similar to how we define CLI using structopt:

(Full)

// Imports are omitted...

#[derive(BotCommand)]
#[command(rename = "lowercase", description = "These commands are supported:")]
enum Command {
    #[command(description = "display this text.")]
    Help,
    #[command(description = "be a cat.")]
    Meow,
    #[command(description = "be a dog.")]
    Woof,
    #[command(description = "be a cow.")]
    Moo,
}

async fn handle_command(
    ctx: DispatcherHandlerCtx<Message>,
) -> Result<(), RequestError> {
    let text = match ctx.update.text() {
        Some(text) => text,
        None => {
            log::info!("Received a message, but not text.");
            Ok(())
        }
    };

    let command = match Command::parse(text) {
        Some((command, _)) => command,
        None => {
            log::info!("Received a text message, but not a command.");
            Ok(())
        }
    };

    match command {
        Command::Help => ctx.answer(Command::descriptions()).send().await?,
        Command::Meow => ctx.answer("I am a cat! Meow!").send().await?,
        Command::Woof => ctx.answer("I am a dog! Woof!").send().await?,
        Command::Moo => ctx.answer("I am a cow! Moo!").send().await?,
    };

    Ok(())
}

#[tokio::main]
async fn main() {
    // Setup is omitted...
}

Guess a number

Wanna see more? This is a bot, which starts a game on each incoming message. You must guess a number from 1 to 10 (inclusively):

(Full)

// Imports are omitted...

#[derive(SmartDefault)]
enum Dialogue {
    #[default]
    Start,
    ReceiveAttempt(u8),
}
async fn handle_message(
    ctx: DialogueHandlerCtx<Message, Dialogue>,
) -> Result<DialogueStage<Dialogue>, RequestError> {
    match ctx.dialogue {
        Dialogue::Start => {
            ctx.answer(
                "Let's play a game! Guess a number from 1 to 10 (inclusively).",
            )
            .send()
            .await?;
            next(Dialogue::ReceiveAttempt(thread_rng().gen_range(1, 11)))
        }
        Dialogue::ReceiveAttempt(secret) => match ctx.update.text() {
            None => {
                ctx.answer("Oh, please, send me a text message!")
                    .send()
                    .await?;
                next(ctx.dialogue)
            }
            Some(text) => match text.parse::<u8>() {
                Ok(attempt) => match attempt {
                    x if !(1..=10).contains(&x) => {
                        ctx.answer(
                            "Oh, please, send me a number in the range [1; \
                             10]!",
                        )
                        .send()
                        .await?;
                        next(ctx.dialogue)
                    }
                    x if x == secret => {
                        ctx.answer("Congratulations! You won!").send().await?;
                        exit()
                    }
                    _ => {
                        ctx.answer("No.").send().await?;
                        next(ctx.dialogue)
                    }
                },
                Err(_) => {
                    ctx.answer(
                        "Oh, please, send me a number in the range [1; 10]!",
                    )
                    .send()
                    .await?;
                    next(ctx.dialogue)
                }
            },
        },
    }
}

#[tokio::main]
async fn main() {
    teloxide::enable_logging!();
    log::info!("Starting guess_a_number_bot!");

    let bot = Bot::from_env();

    Dispatcher::new(bot)
        .message_handler(&DialogueDispatcher::new(|ctx| async move {
            handle_message(ctx)
                .await
                .expect("Something wrong with the bot!")
        }))
        .dispatch()
        .await;
}

Our finite automaton, designating a user dialogue, cannot be in an invalid state. See examples/dialogue_bot to see a bit more complicated bot with dialogues.

Recommendations

• Use this pattern:

#[tokio::main]
async fn main() {
    run().await;
}

async fn run() {
    // Your logic here...
}

Instead of this:

#[tokio::main]
async fn main() {
    // Your logic here...
}

The second one produces very strange compiler messages because of the #[tokio::main] macro. The examples in this README uses the first one for brevity.