Basic play functionality

package.json

@@ -64,10 +64,12 @@
     "@discordjs/opus": "^0.1.0",
     "discord.js": "^12.0.1",
     "dotenv": "^8.2.0",
+    "hasha": "^5.2.0",
     "make-dir": "^3.0.2",
     "node-emoji": "^1.10.0",
     "sequelize": "^5.21.5",
     "sequelize-typescript": "^1.1.0",
-    "sqlite3": "^4.1.1"
+    "sqlite3": "^4.1.1",
+    "ytdl-core": "^2.0.0"
   }
 }

src/commands/play.ts

@@ -0,0 +1,21 @@
+import {CommandHandler} from '../interfaces';
+import {getMostPopularVoiceChannel} from '../utils/channels';
+import getYouTubeStream from '../utils/get-youtube-stream';
+
+const play: CommandHandler = {
+  name: 'play',
+  description: 'plays a song',
+  execute: async (msg, args) => {
+    const url = args[0];
+
+    const channel = getMostPopularVoiceChannel(msg.guild!);
+
+    const conn = await channel.join();
+
+    const stream = await getYouTubeStream(url);
+
+    conn.play(stream, {type: 'webm/opus'});
+  }
+};
+
+export default play;

src/index.ts

@@ -2,7 +2,7 @@ import fs from 'fs';
 import path from 'path';
 import makeDir from 'make-dir';
 import Discord from 'discord.js';
-import {DISCORD_TOKEN, DISCORD_CLIENT_ID, DATA_DIR} from './utils/config';
+import {DISCORD_TOKEN, DISCORD_CLIENT_ID, DATA_DIR, CACHE_DIR} from './utils/config';
 import {Settings} from './models';
 import {sequelize} from './utils/db';
 import {CommandHandler} from './interfaces';
@@ -56,6 +56,7 @@ client.on('message', async (msg: Discord.Message) => {
 client.on('ready', async () => {
   // Create directory if necessary
   await makeDir(DATA_DIR);
+  await makeDir(CACHE_DIR);
 
   await sequelize.sync({});
 

src/utils/channels.ts

@@ -0,0 +1,38 @@
+import {Guild, VoiceChannel} from 'discord.js';
+
+export const getMostPopularVoiceChannel = (guild: Guild, min = 0): VoiceChannel => {
+  interface PopularResult {
+    n: number;
+    channel: VoiceChannel | null;
+  }
+
+  const voiceChannels: PopularResult[] = [];
+
+  for (const [_, channel] of guild.channels.cache) {
+    if (channel.type === 'voice' && channel.members.size >= min) {
+      voiceChannels.push({
+        channel: channel as VoiceChannel,
+        n: channel.members.size
+      });
+    }
+  }
+
+  if (voiceChannels.length === 0) {
+    throw new Error('No voice channels meet minimum size');
+  }
+
+  // Find most popular channel
+  const popularChannel = voiceChannels.reduce((popular: PopularResult, elem: PopularResult) => {
+    if (elem.n > popular.n) {
+      return elem;
+    }
+
+    return popular;
+  }, {n: -1, channel: null});
+
+  if (popularChannel.channel) {
+    return popularChannel.channel;
+  }
+
+  throw new Error();
+};

src/utils/config.ts

@@ -5,3 +5,4 @@ dotenv.config();
 export const DISCORD_TOKEN: string = process.env.DISCORD_TOKEN ? process.env.DISCORD_TOKEN : '';
 export const DISCORD_CLIENT_ID: string = process.env.DISCORD_CLIENT_ID ? process.env.DISCORD_CLIENT_ID : '';
 export const DATA_DIR = path.resolve(process.env.DATA_DIR ? process.env.DATA_DIR : './data');
+export const CACHE_DIR = path.join(DATA_DIR, 'cache');

src/utils/get-youtube-stream.ts

@@ -0,0 +1,51 @@
+import {promises as fs, createReadStream, createWriteStream} from 'fs';
+import {Readable, PassThrough} from 'stream';
+import path from 'path';
+import hasha from 'hasha';
+import ytdl from 'ytdl-core';
+import {CACHE_DIR} from './config';
+
+const nextBestFormat = (formats: ytdl.videoFormat[]): ytdl.videoFormat => {
+  formats = formats
+    .filter(format => format.averageBitrate)
+    .sort((a, b) => b.averageBitrate - a.averageBitrate);
+  return formats.find(format => !format.bitrate) ?? formats[0];
+};
+
+// TODO: are some videos not available in webm/opus?
+export default async (url: string): Promise<Readable> => {
+  const hash = hasha(url);
+  const cachedPath = path.join(CACHE_DIR, `${hash}.webm`);
+
+  const info = await ytdl.getInfo(url);
+
+  const {formats} = info;
+
+  const filter = (format: ytdl.videoFormat): boolean => format.codecs === 'opus' && format.container === 'webm' && format.audioSampleRate !== undefined && parseInt(format.audioSampleRate, 10) === 48000;
+
+  let format = formats.find(filter);
+
+  if (!format) {
+    format = nextBestFormat(info.formats);
+  }
+
+  try {
+    // Test if file exists
+    await fs.access(cachedPath);
+
+    // If so, return cached stream
+    return createReadStream(cachedPath);
+  } catch (_) {
+    // Not yet cached, must download
+    const cacheTempPath = path.join('/tmp', `${hash}.webm`);
+    const cacheStream = createWriteStream(cacheTempPath);
+
+    const pass = new PassThrough();
+
+    pass.pipe(cacheStream).on('finish', async () => {
+      await fs.rename(cacheTempPath, cachedPath);
+    });
+
+    return ytdl.downloadFromInfo(info, {format}).pipe(pass);
+  }
+};

yarn.lock

@@ -1059,6 +1059,19 @@ has-unicode@^2.0.0:
   resolved "https://registry.yarnpkg.com/has-unicode/-/has-unicode-2.0.1.tgz#e0e6fe6a28cf51138855e086d1691e771de2a8b9"
   integrity sha1-4Ob+aijPUROIVeCG0Wkedx3iqLk=
 
+hasha@^5.2.0:
+  version "5.2.0"
+  resolved "https://registry.yarnpkg.com/hasha/-/hasha-5.2.0.tgz#33094d1f69c40a4a6ac7be53d5fe3ff95a269e0c"
+  integrity sha512-2W+jKdQbAdSIrggA8Q35Br8qKadTrqCTC8+XZvBWepKDK6m9XkX6Iz1a2yh2KP01kzAR/dpuMeUnocoLYDcskw==
+  dependencies:
+    is-stream "^2.0.0"
+    type-fest "^0.8.0"
+
+html-entities@^1.1.3:
+  version "1.2.1"
+  resolved "https://registry.yarnpkg.com/html-entities/-/html-entities-1.2.1.tgz#0df29351f0721163515dfb9e5543e5f6eed5162f"
+  integrity sha1-DfKTUfByEWNRXfueVUPl9u7VFi8=
+
 http-signature@~1.2.0:
   version "1.2.0"
   resolved "https://registry.yarnpkg.com/http-signature/-/http-signature-1.2.0.tgz#9aecd925114772f3d95b65a60abb8f7c18fbace1"
@@ -1271,6 +1284,11 @@ is-stream@^1.0.0, is-stream@^1.1.0:
   resolved "https://registry.yarnpkg.com/is-stream/-/is-stream-1.1.0.tgz#12d4a3dd4e68e0b79ceb8dbc84173ae80d91ca44"
   integrity sha1-EtSj3U5o4Lec6428hBc66A2RykQ=
 
+is-stream@^2.0.0:
+  version "2.0.0"
+  resolved "https://registry.yarnpkg.com/is-stream/-/is-stream-2.0.0.tgz#bde9c32680d6fae04129d6ac9d921ce7815f78e3"
+  integrity sha512-XCoy+WlUr7d1+Z8GgSuXmpuUFC9fOhRXglJMx+dwLKTkL44Cjd4W1Z5P+BQZpr+cR93aGP4S/s7Ftw6Nd/kiEw==
+
 is-typedarray@~1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/is-typedarray/-/is-typedarray-1.0.0.tgz#e479c80858df0c1b11ddda6940f96011fcda4a9a"
@@ -1394,6 +1412,14 @@ lru-cache@^4.0.1:
     pseudomap "^1.0.2"
     yallist "^2.1.2"
 
+m3u8stream@^0.6.3:
+  version "0.6.5"
+  resolved "https://registry.yarnpkg.com/m3u8stream/-/m3u8stream-0.6.5.tgz#a41713cb7144f8fe1eb944d32a8848be8cb2c951"
+  integrity sha512-QZCzhcfUliZfsOboi68QkNcMejPKTEhxE+s1TApvHubDeR8ythm4ViWuYFqgUwZeoHe8q0nsPxOvA3lQvdSzyg==
+  dependencies:
+    miniget "^1.6.1"
+    sax "^1.2.4"
+
 make-dir@^1.0.0:
   version "1.3.0"
   resolved "https://registry.yarnpkg.com/make-dir/-/make-dir-1.3.0.tgz#79c1033b80515bd6d24ec9933e860ca75ee27f0c"
@@ -1430,6 +1456,11 @@ mimic-fn@^2.1.0:
   resolved "https://registry.yarnpkg.com/mimic-fn/-/mimic-fn-2.1.0.tgz#7ed2c2ccccaf84d3ffcb7a69b57711fc2083401b"
   integrity sha512-OqbOk5oEQeAZ8WXWydlu9HJjz9WVdEIvamMCcXmuqUYjTknH/sqsWvhQ3vgwKFRR1HpjvNBKQ37nbJgYzGqGcg==
 
+miniget@^1.6.0, miniget@^1.6.1:
+  version "1.7.0"
+  resolved "https://registry.yarnpkg.com/miniget/-/miniget-1.7.0.tgz#a29eb79ebff479e9efafd271616981c603987875"
+  integrity sha512-yrgaDSMRzrfYTkudB4Y6xK8pCb7oAH2bvfv6iPY2m6CedZfs9yK4b/ofh0Vzv08hCYXH/HHkoS8an6fkWtOAQA==
+
 minimatch@^3.0.4:
   version "3.0.4"
   resolved "https://registry.yarnpkg.com/minimatch/-/minimatch-3.0.4.tgz#5166e286457f03306064be5497e8dbb0c3d32083"
@@ -2016,7 +2047,7 @@ safe-buffer@~5.1.0, safe-buffer@~5.1.1:
   resolved "https://registry.yarnpkg.com/safer-buffer/-/safer-buffer-2.1.2.tgz#44fa161b0187b9549dd84bb91802f9bd8385cd6a"
   integrity sha512-YZo3K82SD7Riyi0E1EQPojLz7kpepnSQI9IyPbHHg1XXXevb5dJI7tpyN2ADxGcQbHG7vcyRHk0cbwqcQriUtg==
 
-sax@^1.2.4:
+sax@^1.1.3, sax@^1.2.4:
   version "1.2.4"
   resolved "https://registry.yarnpkg.com/sax/-/sax-1.2.4.tgz#2816234e2378bddc4e5354fab5caa895df7100d9"
   integrity sha512-NqVDv9TpANUjFm0N8uM5GxL36UgKi9/atZw+x7YFnQ8ckwFGKrl4xX4yWtrey3UJm5nP1kUbnYgLopqWNSRhWw==
@@ -2399,7 +2430,7 @@ type-fest@^0.11.0:
   resolved "https://registry.yarnpkg.com/type-fest/-/type-fest-0.11.0.tgz#97abf0872310fed88a5c466b25681576145e33f1"
   integrity sha512-OdjXJxnCN1AvyLSzeKIgXTXxV+99ZuXl3Hpo9XpJAv9MBcHrrJOQ5kV7ypXOuQie+AmWG25hLbiKdwYTifzcfQ==
 
-type-fest@^0.8.1:
+type-fest@^0.8.0, type-fest@^0.8.1:
   version "0.8.1"
   resolved "https://registry.yarnpkg.com/type-fest/-/type-fest-0.8.1.tgz#09e249ebde851d3b1e48d27c105444667f17b83d"
   integrity sha512-4dbzIzqvjtgiM5rw1k5rEHtBANKmdudhGyBEajN01fEyhaAIhsoKNy6y7+IN93IfpFtwY9iqi7kD+xwKhQsNJA==
@@ -2577,3 +2608,13 @@ yn@3.1.1:
   version "3.1.1"
   resolved "https://registry.yarnpkg.com/yn/-/yn-3.1.1.tgz#1e87401a09d767c1d5eab26a6e4c185182d2eb50"
   integrity sha512-Ux4ygGWsu2c7isFWe8Yu1YluJmqVhxqK2cLXNQA5AcC3QfbGNpM7fu0Y8b/z16pXLnFxZYvWhd3fhBY9DLmC6Q==
+
+ytdl-core@^2.0.0:
+  version "2.0.0"
+  resolved "https://registry.yarnpkg.com/ytdl-core/-/ytdl-core-2.0.0.tgz#09bafc2beeab1eb9c69ceb9ca8f406be12396613"
+  integrity sha512-cYdcxXhgldJeOaWaN/mxT+j07XFZdR+qUqfz5eddx4WcyWCha66FfJvmQBOPqyQo1TCyj/IkgZqdGADWlNdTcQ==
+  dependencies:
+    html-entities "^1.1.3"
+    m3u8stream "^0.6.3"
+    miniget "^1.6.0"
+    sax "^1.1.3"