Lavalink JDA Client

Installation

Lavalink does not have a maven repository and instead uses Jitpack. You can add the following to your POM if you're using Maven:

<dependencies>
    <dependency>
        <groupId>com.github.Frederikam</groupId>
        <artifactId>Lavalink</artifactId>
        <version>version-goes-here</version>
        <exclusions>
            <exclusion>
                <!-- Exclude the server module -->
                <groupId>com.github.Frederikam.Lavalink</groupId>
                <artifactId>Lavalink-Server</artifactId>
            </exclusion>
        </exclusions>
    </dependency>
</dependencies>

<repositories>
    <repository>
        <id>jitpack.io</id>
        <url>https://jitpack.io</url>
    </repository>
</repositories>

Jitpack versions

Jitpack versioning is based on git branches and commit hashes. Eg:

abfb66cc25f5f121e5441726ad70095aee161c71
master-SNAPSHOT
dev-SNAPSHOT

Usage

FredBoat is a great reference.

Configuring Lavalink

All your shards should share a single Lavalink instance. Here is how to construct an instance:

Lavalink lavalink = new Lavalink(
                myDiscordUserId,
                fixedNumberOfShards,
                shardId -> getJdaInstanceFromId(shardId)
        );

The interesting part is the third parameter, which is a Function<Integer, JDA>. You must define this Function so that Lavalink can get your current JDA instance for that shardId.

You can now register remote nodes to your Lavalink instance:

lavalink.addNode("ws://example.com", "my-secret-password");

If a node is down Lavalink will continue trying to connect until you remove the node. When a node dies Lavalink will attempt to balance the load unto other nodes if they are available.

Next when you are building a shard, you must register Lavalink as an event listener to bind your shard. You may not register more than one Lavalink instance per shard.

new JDABuilder(AccountType.BOT)
        .addEventListener(LavalinkManager.ins.getLavalink())
        ...

The Link class

The Link class is the state of one of your guilds in relation to Lavalink. A Link object is instantiated if it doesn't exist already when invoking Lavalink#getLink(Guild/String).

Link someLink = myLavalink.getLink(someGuild);
someLink = myLavalink.getLink(someGuildId);

Here are a few important methods:

• connect(VoiceChannel channel) connects you to a VoiceChannel.
  • Note: This also works for moving to a new channel, in which case we will disconnect first.
• disconnect() disconnects from the VoiceChannel.
• destroy() resets the state of the Link and removes Lavalink's internal reference to this Link. This Link should be discarded.
• getPlayer() returns an IPlayer you can use to play music with.

The IPlayer more or less works like a drop-in replacement for Lavaplayer's AudioPlayer. Which leads me to...

Warning: You should not use JDA's AudioManager#openAudioConnection() or AudioManager#closeAudioConnection() when Lavalink is being used. Use Link instead.

Using Lavalink and Lavaplayer in the same codebase

One of the requirements for Lavalink to work with FredBoat was to make Lavalink optional, so we can support selfhosters who do not want to run Lavalink. In FredBoat this is accomplished with the LavalinkManager class.

Lavalink-Client adds an abstraction layer:

• IPlayer in place of AudioPlayer
• IPlayerEventListener in place of AudioEventListener
• PlayerEventListenerAdapter in place of AudioEventAdapter

What this means is that if you want to use Lavaplayer directly instead, you can still use IPlayer.

IPlayer myNewPlayer = isLavalinkEnabled
        ? lavalink.getLink(guildId).getPlayer()
        : new LavaplayerPlayerWrapper(myLavaplayerPlayerManager.createPlayer());

Node statistics

Lavalink-Client allows access to the client WebSockets with Lavalink#getNodes(). This is useful if you want to read the statistics and state of a node connection.

Useful methods:

• isAvailable() Whether or not we are connected and can play music.
• getRemoteUri() Returns a URI of the remote address.
• getStats() Returns a nullable RemoteStats object, with statistics from the Lavalink Server. Updated every minute.