Create basic voice receiving

src/client/voice/VoiceConnection.js

@@ -1,5 +1,6 @@
 const VoiceConnectionWebSocket = require('./VoiceConnectionWebSocket');
 const VoiceConnectionUDPClient = require('./VoiceConnectionUDPClient');
+const VoiceReceiver = require('./receiver/VoiceReceiver');
 const Constants = require('../../util/Constants');
 const EventEmitter = require('events').EventEmitter;
 const DefaultPlayer = require('./player/DefaultPlayer');
@@ -179,6 +180,14 @@ class VoiceConnection extends EventEmitter {
   playStream(stream) {
     return this.player.playStream(stream);
   }
+
+  /**
+   * Creates a VoiceReceiver so you can start listening to voice data. It's recommended to only create one of these.
+   * @returns {VoiceReceiver}
+   */
+  createReceiver() {
+    return new VoiceReceiver(this);
+  }
 }
 
 module.exports = VoiceConnection;

src/client/voice/receiver/VoiceReceiver.js

@@ -0,0 +1,45 @@
+const EventEmitter = require('events').EventEmitter;
+const NaCl = require('tweetnacl');
+
+const nonce = new Buffer(24);
+nonce.fill(0);
+
+/**
+ * Receives voice data from a voice connection.
+ * @extends {EventEmitter}
+ */
+class VoiceReceiver extends EventEmitter {
+  constructor(connection) {
+    super();
+    /**
+     * The VoiceConnection that instantiated this
+     * @type {VoiceConnection}
+     */
+    this.connection = connection;
+    this.connection.udp.udpSocket.on('message', msg => {
+      msg.copy(nonce, 0, 0, 12);
+      let data = NaCl.secretbox.open(msg.slice(12), nonce, this.connection.data.secret);
+      if (!data) {
+        return this.emit('warn', 'failed to decrypt voice packet');
+      }
+      data = new Buffer(data);
+      /**
+       * Emitted whenever voice data is received from the voice connection. This is _always_ emitted (unlike PCM).
+       * @event VoiceReceiver#opus
+       * @param {Buffer} buffer the opus buffer
+       */
+      this.emit('opus', data);
+      if (this.listenerCount('pcm') > 0) {
+        /**
+         * Emits decoded voice data when it's received. For performance reasons, the decoding will only
+         * happen if there is at least one `pcm` listener on this receiver.
+         * @event VoiceReceiver#pcm
+         * @param {Buffer} buffer the decoded buffer
+         */
+        this.emit('pcm', this.connection.player.opusEncoder.decode(data));
+      }
+    });
+  }
+}
+
+module.exports = VoiceReceiver;

test/random.js

@@ -144,6 +144,8 @@ client.on('message', msg => {
         const disp = conn.player.playStream(ytdl('https://www.youtube.com/watch?v=nbXgHAzUWB0', {filter : 'audioonly'}));
         conn.player.on('debug', console.log);
         conn.player.on('error', err => console.log(123, err));
+        const receiver = conn.createReceiver();
+        receiver.on('pcm', console.log);
         disp.on('error', err => console.log(123, err));
       })
       .catch(console.log);