Alter YouTube music handler to get an audio-only Opus format, to incr…

…ease speed of caching

src/cmd/main/music/handlers/YouTubeHandler.js

@@ -6,40 +6,32 @@
 const ytdl = require('ytdl-core');
 const got = require('got');
 
+const ITAG = '251'; // Preferred iTag quality to get. Default: 251.
+
 class YouTubeHandler {
     constructor() {}
 
-    getInfo(url) {
-        return new Promise((resolve, reject) => {
-            if (typeof url !== 'string') throw new TypeError('url is not a string.');
-
-            ytdl.getInfo(url, {filter: 'audioonly'}).then(info => {
-                let res = {
-                    url,
-                    title: info.title,
-                    uploader: info.author.name,
-                    thumbnail: info.thumbnail_url.replace('default.jpg', 'hqdefault.jpg'),
-                    length: Number(info.length_seconds),
-                    type: 'YouTubeVideo'
-                };
-
-                return res;
-            }).then(resolve).catch(reject);
-        });
+    async getInfo(url) {
+        if (typeof url !== 'string') throw new TypeError('url is not a string.');
+
+        let info = await ytdl.getInfo(url);
+        let res = {
+            url,
+            title: info.title,
+            uploader: info.author.name,
+            thumbnail: info.thumbnail_url.replace('default.jpg', 'hqdefault.jpg'),
+            length: Number(info.length_seconds),
+            type: 'YouTubeVideo'
+        };
+
+        return res;
     }
 
-    getStream(url) {
-        return new Promise((resolve, reject) => {
-            if (typeof url !== 'string') throw new TypeError('url is not a string.');
+    async getStream(url) {
+        if (typeof url !== 'string') throw new TypeError('url is not a string.');
 
-            ytdl.getInfo(url, {filter: 'audioonly'}).then(info => {
-                // Sort the various bitrates and pick the highest quality (that is 96kbps or less)
-                let bitrates = info.formats.filter(f => f.audioBitrate <= 96 && typeof f.audioBitrate === 'number');
-                bitrates = bitrates.map(f => {return {bitrate: f.bitrate, url: f.url};}).sort((a, b) => b.bitrate - a.bitrate);
-
-                return got.stream(bitrates[0].url);
-            }).then(resolve).catch(reject);
-        });
+        let info = await ytdl.getInfo(url)
+        return got.stream(info.formats.find(f => f.itag === ITAG).url);
     }
 }