twilight

twilight is a powerful, flexible, and scalable ecosystem of Rust libraries for the Discord API.

The ecosystem of first-class crates includes twilight-cache-inmemory, twilight-command-parser, twilight-gateway, twilight-http, twilight-model, and more. These are explained in detail below.

The main twilight crate is purely an advertisement crate: it has no functionality. Please use the individual crates listed below instead!

Installation

Twilight supports a MSRV of Rust 1.48+.

We recommend that most users start out with these crates added to your Cargo.toml's [dependencies] section:

twilight-cache-inmemory = "0.2"
twilight-gateway = "0.2"
twilight-http = "0.2"
twilight-model = "0.2"

If you need any other functionality that Twilight provides, you can just add that dependency in.

Core Crates

These are essential crates that most users will use together for a full development experience. You may not need all of these - such as twilight-command-parser - but they are often used together to accomplish most of what you need.

`twilight-model`

Models defining structures, enums, and bitflags for the entirety of the Discord API. It is split into a number of sub-modules, such as gateway for containing the WebSocket gateway types, guild for containing types owned by guilds (servers), voice containing the types used by the Voice WebSocket API, and more.

These are all in a single crate so that you can use gateway models without depending on twilight-gateway. One use case is if you write your own WebSocket gateway implementation.

`twilight-cache-inmemory`

In-process-memory based cache over objects received from the gateway. It's responsible for holding and managing information about things like guilds, channels, role information, voice states, and any other events that come from Discord.

`twilight-gateway`

Implementation of Discord's sharding gateway sessions. This is responsible for receiving stateful events in real-time from Discord and sending some stateful information.

`twilight-command-parser`

Helpful crate for parsing commands out of messages received over the gateway. It finds messages commanding your bot and parses the arguments out.

`twilight-http`

HTTP client supporting all of the Discord REST API. It is based on hyper. It meets Discord's ratelimiting requirements and supports proxying.

`twilight-standby`

Event processor that allows for tasks to wait for an event to come in. This is useful, for example, when you have a reaction menu and want to wait for a specific reaction on it to come in.

Additional Crates

These are crates that are officially supported by Twilight, but aren't considered core crates due to being vendor-specific or non-essential for most users.

`twilight-embed-builder`

Utility crate for creating and validating message embeds, to be used when creating or updating messages.

`twilight-lavalink`

Client for Lavalink as part of the twilight ecosystem.

It includes support for managing multiple nodes, a player manager for conveniently using players to send events and retrieve information for each guild, and an HTTP module for creating requests using the http crate and providing models to deserialize their responses.

Examples

use std::{env, error::Error};
use tokio::stream::StreamExt;
use twilight_cache_inmemory::{EventType, InMemoryCache};
use twilight_gateway::{cluster::{Cluster, ShardScheme}, Event};
use twilight_http::Client as HttpClient;
use twilight_model::gateway::Intents;

#[tokio::main]
async fn main() -> Result<(), Box<dyn Error + Send + Sync>> {
    let token = env::var("DISCORD_TOKEN")?;

    // This is the default scheme. It will automatically create as many
    // shards as is suggested by Discord.
    let scheme = ShardScheme::Auto;

    // Use intents to only receive guild message events.
    let cluster = Cluster::builder(&token, Intents::GUILD_MESSAGES)
        .shard_scheme(scheme)
        .build()
        .await?;

    // Start up the cluster.
    let cluster_spawn = cluster.clone();

    // Start all shards in the cluster in the background.
    tokio::spawn(async move {
        cluster_spawn.up().await;
    });

    // HTTP is separate from the gateway, so create a new client.
    let http = HttpClient::new(&token);

    // Since we only care about new messages, make the cache only
    // cache new messages.
    let cache = InMemoryCache::builder()
        .event_types(
            EventType::MESSAGE_CREATE
                | EventType::MESSAGE_DELETE
                | EventType::MESSAGE_DELETE_BULK
                | EventType::MESSAGE_UPDATE,
        )
        .build();

    let mut events = cluster.events();

    // Process each event as they come in.
    while let Some((shard_id, event)) = events.next().await {
        // Update the cache with the event.
        cache.update(&event);

        tokio::spawn(handle_event(shard_id, event, http.clone()));
    }

    Ok(())
}

async fn handle_event(
    shard_id: u64,
    event: Event,
    http: HttpClient,
) -> Result<(), Box<dyn Error + Send + Sync>> {
    match event {
        Event::MessageCreate(msg) if msg.content == "!ping" => {
            http.create_message(msg.channel_id).content("Pong!")?.await?;
        }
        Event::ShardConnected(_) => {
            println!("Connected on shard {}", shard_id);
        }
        // Other events here...
        _ => {}
    }

    Ok(())
}

Note about tracing

When using the tracing crate you won't, by default, see logs from any libraries that use the log crate. You can add that back by using the tracing-log crate and initializing it like this:

tracing_log::LogTracer::init()?;

License

All first-party crates are licensed under ISC

LavaToaster/twilight