Youtube download button

Adds a download button

您需要先安装一个扩展,例如 篡改猴Greasemonkey暴力猴,之后才能安装此脚本。

You will need to install an extension such as Tampermonkey to install this script.

您需要先安装一个扩展,例如 篡改猴暴力猴,之后才能安装此脚本。

您需要先安装一个扩展,例如 篡改猴Userscripts ,之后才能安装此脚本。

您需要先安装一款用户脚本管理器扩展,例如 Tampermonkey,才能安装此脚本。

您需要先安装用户脚本管理器扩展后才能安装此脚本。

(我已经安装了用户脚本管理器,让我安装!)

您需要先安装一款用户样式管理器扩展,比如 Stylus,才能安装此样式。

您需要先安装一款用户样式管理器扩展,比如 Stylus,才能安装此样式。

您需要先安装一款用户样式管理器扩展,比如 Stylus,才能安装此样式。

您需要先安装一款用户样式管理器扩展后才能安装此样式。

您需要先安装一款用户样式管理器扩展后才能安装此样式。

您需要先安装一款用户样式管理器扩展后才能安装此样式。

(我已经安装了用户样式管理器,让我安装!)

// ==UserScript==
// @name        Youtube download button
// @namespace   Violentmonkey Scripts
// @match       https://www.youtube.com/watch
// @include     https://*.youtube.com/*
// @grant       GM_addStyle
// @run-at      document-start
// @version     3.0
// @author      Nojyto
// @license     MIT
// @description Adds a download button
// ==/UserScript==

(function() {
    const TEXT_BUTTON = "Download";
    const SVG_NAMESPACE = "http://www.w3.org/2000/svg";
    const ICON_SVG_PATH_DATA = "M17 18v1H6v-1h11zm-.5-6.6-.7-.7-3.8 3.7V4h-1v10.4l-3.8-3.8-.7.7 5 5 5-4.9z";

    const DOWNLOAD_API = "https://www.y2mate.com/download-youtube/";
    const BUTTON_ID = "ytDownloadButton";
    const TARGET_CONTAINER_SELECTOR = "div#owner";

    let lastUrl = null;
    let currentVideoId = null;
    let buttonObserver = null;

    GM_addStyle(`
        #${BUTTON_ID} {
            background-color: var(--yt-spec-additive-background);
            color: var(--yt-spec-text-primary);
            margin: 0px 4px;
            border-radius: 18px;
            width: 120px;
            height: 36px;
            line-height: 37px;
            text-align: center;
            font-style: normal;
            font-size: 14px;
            font-family: Roboto, Noto, sans-serif;
            font-weight: 500;
            text-decoration: none;
            display: flex;
            align-items: center;
            justify-content: center;
            cursor: pointer;
            transition: background-color 0.2s;
            white-space: nowrap;
            min-width: fit-content;
            padding: 0 10px;
        }
        #${BUTTON_ID}:hover {
            background-color: var(--yt-spec-mono-tonal-hover);
            color: var(--yt-spec-text-primary);
        }
        #${BUTTON_ID} .yt-download-icon-container {
            height: 84%;
            margin-left: -8px;
            fill: currentcolor;
            display: flex;
            align-items: center;
            justify-content: center;
        }
        #${BUTTON_ID} > span {
            margin-left: 4px;
        }
        #owner {
            display: flex;
            align-items: center;
            flex-wrap: wrap;
        }
    `);

    function waitForElement(selector) {
        // console.log(`[Youtube Download] Waiting for element: ${selector}`);
        return new Promise((resolve) => {
            const element = document.querySelector(selector);
            if (element) {
                // console.log(`[Youtube Download] Element found immediately:`, element);
                return resolve(element);
            }
            const observer = new MutationObserver((mutationsList, obs) => {
                const foundElement = document.querySelector(selector);
                if (foundElement) {
                    obs.disconnect();
                    // console.log(`[Youtube Download] Element found via MutationObserver:`, foundElement);
                    resolve(foundElement);
                }
            });
            observer.observe(document.documentElement, { childList: true, subtree: true });
        });
    }

    function getVideoId(url) {
        try {
            const urlObj = new URL(url);
            const urlParams = new URLSearchParams(urlObj.search);
            return urlParams.get('v');
        } catch (e) {
            console.error("[Youtube Download] Error parsing URL to get video ID:", e);
            return null;
        }
    }

    async function addOrUpdateDownloadButton() {
        // console.log("[Youtube Download] addOrUpdateDownloadButton called.");
        const currentUrl = window.location.href;

        if (!currentUrl.includes("watch?v=")) {
            // console.log("[Youtube Download] Not a YouTube watch page. Skipping.");
            return;
        }

        const targetContainer = await waitForElement(TARGET_CONTAINER_SELECTOR);
        if (!targetContainer) {
            console.warn("[Youtube Download] Target container element not found after waiting. Cannot add download button.");
            return;
        }
        // console.log(`[Youtube Download] Found target container:`, targetContainer);

        let downloadLink = document.getElementById(BUTTON_ID);
        let videoIdForCurrentUrl = getVideoId(currentUrl);

        if (!videoIdForCurrentUrl) {
            console.warn("[Youtube Download] Could not get video ID for current URL:", currentUrl);
            return;
        }

        if (!downloadLink || downloadLink.parentNode !== targetContainer) {
            // console.log("[Youtube Download] Button missing or detached. Creating/re-creating download button.");
            if (downloadLink && downloadLink.parentNode) {
                downloadLink.parentNode.removeChild(downloadLink);
                // console.log("[Youtube Download] Removed detached old button instance.");
            }

            downloadLink = document.createElement('a');
            downloadLink.id = BUTTON_ID;
            downloadLink.target = "_blank";
            downloadLink.rel = "noopener noreferrer";

            const iconWrapper = document.createElement('div');
            iconWrapper.className = 'yt-download-icon-container';
            const svgElement = document.createElementNS(SVG_NAMESPACE, "svg");
            svgElement.setAttribute("height", "24");
            svgElement.setAttribute("viewBox", "0 0 24 24");
            svgElement.setAttribute("width", "24");
            svgElement.setAttribute("focusable", "false");
            svgElement.style.pointerEvents = "none";
            svgElement.style.display = "inherit";
            svgElement.style.width = "100%";
            svgElement.style.height = "100%";
            const pathElement = document.createElementNS(SVG_NAMESPACE, "path");
            pathElement.setAttribute("d", ICON_SVG_PATH_DATA);
            svgElement.appendChild(pathElement);
            iconWrapper.appendChild(svgElement);
            downloadLink.appendChild(iconWrapper);

            const textSpan = document.createElement('span');
            textSpan.textContent = TEXT_BUTTON;
            downloadLink.appendChild(textSpan);

            targetContainer.appendChild(downloadLink);
            // console.log("[Youtube Download] Download button created and inserted into container.");

            setupButtonObserver(targetContainer);
        } else {
            // console.log("[Youtube Download] Button exists and is in place.");
            if (!buttonObserver || buttonObserver.observedElement !== targetContainer) {
                setupButtonObserver(targetContainer);
            }
        }

        if (currentUrl !== lastUrl || !lastUrl || !downloadLink.href.includes(videoIdForCurrentUrl)) {
             lastUrl = currentUrl;
             currentVideoId = videoIdForCurrentUrl;
             downloadLink.href = DOWNLOAD_API + currentVideoId;
            //  console.log(`[Youtube Download] Button href updated to: ${downloadLink.href}`);
        } else {
            //  console.log("[Youtube Download] URL unchanged, button already updated. No action needed for href.");
        }
    }

    function setupButtonObserver(parentEl) {
        if (buttonObserver) {
            buttonObserver.disconnect();
            // console.log("[Youtube Download] Existing button observer disconnected.");
        }

        buttonObserver = new MutationObserver((mutationsList) => {
            let downloadLink = document.getElementById(BUTTON_ID);
            if (!downloadLink) {
                // console.log("[Youtube Download] Download button detected as removed. Attempting to re-add.");
                if (buttonObserver) {
                    buttonObserver.disconnect();
                    buttonObserver = null;
                }
                setTimeout(() => addOrUpdateDownloadButton(), 500);
            }
        });

        buttonObserver.observedElement = parentEl;
        buttonObserver.observe(parentEl, { childList: true, subtree: false });
        // console.log("[Youtube Download] Button observer set up on:", parentEl);
    }

    if (document.readyState === 'loading') {
        // console.log("[Youtube Download] DOM still loading, adding DOMContentLoaded listener.");
        document.addEventListener('DOMContentLoaded', addOrUpdateDownloadButton);
    } else {
        // console.log("[Youtube Download] DOM already loaded, running addOrUpdateDownloadButton immediately.");
        addOrUpdateDownloadButton();
    }
    window.addEventListener("yt-navigate-finish", addOrUpdateDownloadButton, true);
    // console.log("[Youtube Download] Script initialized. Listening for navigation events.");
})();