Add downloader (video -> mp3) plugin (in music menu)

plugins/downloader/actions.js

@@ -0,0 +1,9 @@
+const CHANNEL = "downloader";
+const ACTIONS = {
+	ERROR: "error",
+};
+
+module.exports = {
+	CHANNEL: CHANNEL,
+	ACTIONS: ACTIONS,
+};

plugins/downloader/back.js

@@ -0,0 +1,33 @@
+const { join } = require("path");
+
+const { dialog } = require("electron");
+
+const { injectCSS, listenAction } = require("../utils");
+const { ACTIONS, CHANNEL } = require("./actions.js");
+
+const sendError = (win, err) => {
+	const dialogOpts = {
+		type: "info",
+		buttons: ["OK"],
+		title: "Error in download!",
+		message: "Argh! Apologies, download failed…",
+		detail: err.toString(),
+	};
+	dialog.showMessageBox(dialogOpts);
+};
+
+function handle(win) {
+	injectCSS(win.webContents, join(__dirname, "style.css"));
+
+	listenAction(CHANNEL, (event, action, error) => {
+		switch (action) {
+			case ACTIONS.ERROR:
+				sendError(win, error);
+				break;
+			default:
+				console.log("Unknown action: " + action);
+		}
+	});
+}
+
+module.exports = handle;

plugins/downloader/front.js

@@ -0,0 +1,54 @@
+const { ElementFromFile, templatePath, triggerAction } = require("../utils");
+const { ACTIONS, CHANNEL } = require("./actions.js");
+const { downloadVideoToMP3 } = require("./youtube-dl");
+
+let menu = null;
+let progress = null;
+const downloadButton = ElementFromFile(
+	templatePath(__dirname, "download.html")
+);
+
+const observer = new MutationObserver((mutations, observer) => {
+	if (!menu) {
+		menu = document.querySelector("ytmusic-menu-popup-renderer paper-listbox");
+	}
+
+	if (menu && !menu.contains(downloadButton)) {
+		menu.prepend(downloadButton);
+		progress = document.querySelector("#ytmcustom-download");
+	}
+});
+
+global.download = () => {
+	const videoUrl = window.location.href;
+
+	downloadVideoToMP3(
+		videoUrl,
+		(feedback) => {
+			if (!progress) {
+				console.warn("Cannot update progress");
+			} else {
+				progress.innerHTML = feedback;
+			}
+		},
+		(error) => {
+			triggerAction(CHANNEL, ACTIONS.ERROR, error);
+		},
+		() => {
+			if (!progress) {
+				console.warn("Cannot update progress");
+			} else {
+				progress.innerHTML = "Download";
+			}
+		}
+	);
+};
+
+function observeMenu() {
+	observer.observe(document, {
+		childList: true,
+		subtree: true,
+	});
+}
+
+module.exports = observeMenu;

plugins/downloader/style.css

@@ -0,0 +1,13 @@
+.menu-item {
+	display: var(--ytmusic-menu-item_-_display);
+	height: var(--ytmusic-menu-item_-_height);
+	align-items: var(--ytmusic-menu-item_-_align-items);
+	padding: var(--ytmusic-menu-item_-_padding);
+	cursor: pointer;
+}
+
+.menu-icon {
+	flex: var(--ytmusic-menu-item-icon_-_flex);
+	margin: var(--ytmusic-menu-item-icon_-_margin);
+	fill: var(--ytmusic-menu-item-icon_-_fill);
+}

plugins/downloader/templates/download.html

@@ -0,0 +1,37 @@
+<div
+	class="menu-item ytmusic-menu-popup-renderer"
+	role="option"
+	tabindex="-1"
+	aria-disabled="false"
+	aria-selected="false"
+	onclick="download()"
+>
+	<div
+		class="menu-icon yt-icon-container yt-icon ytmusic-toggle-menu-service-item-renderer"
+	>
+		<svg
+			viewBox="0 0 24 24"
+			preserveAspectRatio="xMidYMid meet"
+			focusable="false"
+			class="style-scope yt-icon"
+			style="pointer-events: none; display: block; width: 100%; height: 100%;"
+		>
+			<g class="style-scope yt-icon">
+				<path
+					d="M25.462,19.105v6.848H4.515v-6.848H0.489v8.861c0,1.111,0.9,2.012,2.016,2.012h24.967c1.115,0,2.016-0.9,2.016-2.012v-8.861H25.462z"
+					class="style-scope yt-icon"
+				/>
+				<path
+					d="M14.62,18.426l-5.764-6.965c0,0-0.877-0.828,0.074-0.828s3.248,0,3.248,0s0-0.557,0-1.416c0-2.449,0-6.906,0-8.723c0,0-0.129-0.494,0.615-0.494c0.75,0,4.035,0,4.572,0c0.536,0,0.524,0.416,0.524,0.416c0,1.762,0,6.373,0,8.742c0,0.768,0,1.266,0,1.266s1.842,0,2.998,0c1.154,0,0.285,0.867,0.285,0.867s-4.904,6.51-5.588,7.193C15.092,18.979,14.62,18.426,14.62,18.426z"
+					class="style-scope yt-icon"
+				/>
+			</g>
+		</svg>
+	</div>
+	<div
+		class="text style-scope ytmusic-toggle-menu-service-item-renderer"
+		id="ytmcustom-download"
+	>
+		Download
+	</div>
+</div>

plugins/downloader/youtube-dl.js

@@ -0,0 +1,89 @@
+const { randomBytes } = require("crypto");
+const { writeFileSync } = require("fs");
+const { join } = require("path");
+
+const downloadsFolder = require("downloads-folder");
+const is = require("electron-is");
+const filenamify = require("filenamify");
+
+// Browser version of FFmpeg (in renderer process) instead of loading @ffmpeg/ffmpeg
+// because --js-flags cannot be passed in the main process when the app is packaged
+// See https://github.com/electron/electron/issues/22705
+const FFmpeg = require("@ffmpeg/ffmpeg/dist/ffmpeg.min");
+const ytdl = require("ytdl-core");
+
+const { createFFmpeg } = FFmpeg;
+const ffmpeg = createFFmpeg({
+	log: false,
+	logger: () => {}, // console.log,
+	progress: () => {}, // console.log,
+});
+
+const downloadVideoToMP3 = (videoUrl, sendFeedback, sendError, reinit) => {
+	sendFeedback("Downloading…");
+
+	let videoName = "YouTube Music - Unknown title";
+	let videoReadableStream;
+	try {
+		videoReadableStream = ytdl(videoUrl, {
+			filter: "audioonly",
+			quality: "highestaudio",
+			highWaterMark: 32 * 1024 * 1024, // 32 MB
+		});
+	} catch (err) {
+		sendError(err);
+		return;
+	}
+
+	const chunks = [];
+	videoReadableStream
+		.on("data", (chunk) => {
+			chunks.push(chunk);
+		})
+		.on("progress", (chunkLength, downloaded, total) => {
+			const progress = Math.floor((downloaded / total) * 100);
+			sendFeedback("Download: " + progress + "%");
+		})
+		.on("info", (info, format) => {
+			videoName = info.videoDetails.title.replace("|", "").toString("ascii");
+			if (is.dev()) {
+				console.log("Downloading video - name:", videoName);
+			}
+		})
+		.on("error", sendError)
+		.on("end", () => {
+			const buffer = Buffer.concat(chunks);
+			toMP3(videoName, buffer, sendFeedback, sendError, reinit);
+		});
+};
+
+const toMP3 = async (videoName, buffer, sendFeedback, sendError, reinit) => {
+	const safeVideoName = randomBytes(32).toString("hex");
+
+	try {
+		if (!ffmpeg.isLoaded()) {
+			sendFeedback("Loading…");
+			await ffmpeg.load();
+		}
+
+		sendFeedback("Preparing file…");
+		ffmpeg.FS("writeFile", safeVideoName, buffer);
+
+		sendFeedback("Converting…");
+		await ffmpeg.run("-i", safeVideoName, safeVideoName + ".mp3");
+
+		const filename = filenamify(videoName + ".mp3", { replacement: "_" });
+		writeFileSync(
+			join(downloadsFolder(), filename),
+			ffmpeg.FS("readFile", safeVideoName + ".mp3")
+		);
+
+		reinit();
+	} catch (e) {
+		sendError(e);
+	}
+};
+
+module.exports = {
+	downloadVideoToMP3,
+};