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给知乎的视频播放器添加下载功能
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// ==UserScript==
// @name 下载知乎视频
// @version 0.8
// @description 给知乎的视频播放器添加下载功能
// @author Chao
// @include *://www.zhihu.com/*
// @match *://www.zhihu.com/*
// @include https://v.vzuu.com/video/*
// @match https://v.vzuu.com/video/*
// @connect zhihu.com
// @connect vzuu.com
// @grant GM_download
// @namespace https://greasyfork.org/users/38953
// ==/UserScript==
(async () => {
if (window.location.host == 'www.zhihu.com') return;
const playlistBaseUrl = 'https://lens.zhihu.com/api/videos/';
const videoId = window.location.pathname.split('/').pop(); // 视频id
const menuStyle = 'transform:none !important; left:auto !important; right:-0.5em !important;';
const controlBarSelector = '#player > div:first-child > div:last-child > div:last-child > div:first-child';
const svgDownload = '<path d="M9.5,4 H14.5 V10 H17.8 L12,15.8 L6.2,10 H9.5 Z M6.2,18 H17.8 V20 H6.2 Z"></path>';
const svgCircle = '<circle cx="12" cy="12" r="8" fill="none" stroke-width="2" stroke="#555" />' +
'<text x="50%" y="50%" dy=".4em" text-anchor="middle" fill="#fff" font-size="9">0</text>' +
'<path fill="none" r="8" transform="translate(12,12)" stroke-width="2" stroke="#fff" />';
const domControlBar = document.querySelector(controlBarSelector);
const domFullScreenBtn = document.querySelector(controlBarSelector + '> div:nth-last-of-type(1)');
const domResolutionBtn = document.querySelector(controlBarSelector + '> div:nth-last-of-type(3)');
let domDownloadBtn = domResolutionBtn.cloneNode(true); // 克隆分辨率按钮为下载按钮
let domMenuItem = domDownloadBtn.querySelectorAll('button')[1];
let domMenu = domMenuItem.parentNode;
let videos = []; // 存储各分辨率的视频信息
let blobs = null; // 存储视频段
let ratio;
let errors = 0;
function wait(time) {
return new Promise(function (resolve, reject) {
setTimeout(resolve, time);
});
};
function fetchRetry(url, options = {}, times = 1, delay = 1000, checkStatus = true) {
return new Promise((resolve, reject) => {
// fetch 成功处理函数
function success(res) {
if (checkStatus && !res.ok) {
failure(res);
} else {
resolve(res);
}
}
// 单次失败处理函数
function failure(error) {
times--;
if (times) {
setTimeout(fetchUrl, delay);
}
else {
reject(error);
}
}
// 总体失败处理函数
function finalHandler(error) {
throw error;
}
function fetchUrl() {
return fetch(url, options)
.then(success)
.catch(failure)
.catch(finalHandler);
}
fetchUrl();
});
}
function fileSize(size) {
let n = Math.log(size) / Math.log(1024) | 0;
return (size / Math.pow(1024, n)).toFixed(0) + ' ' + (n ? 'KMGTPEZY'[--n] + 'B' : 'Bytes');
};
// 下载 m3u8 文件
async function downloadM3u8(url) {
const res = await fetchRetry(url, {}, 3);
const m3u8 = await res.text();
let i = 0;
blobs = [];
ratio = 0;
errors = 0;
// 初始化进度显示
domDownloadBtn.querySelector('svg').innerHTML = svgCircle;
m3u8.split('\n').forEach(function (line) {
if (line.match(/\.ts/)) {
blobs[i] = undefined;
downloadTs(url.replace(/\/[^\/]+?$/, '/' + line), i++);
}
});
};
// 下载 m3u8 文件中的单个 ts 文件
async function downloadTs(url, order) {
let res;
let blob;
try {
res = await fetchRetry(url, {}, 5);
blob = await res.blob();
} catch (e) {
if (++errors == 1) {
resetDownloadIcon();
alert('下载视频失败，请重新下载。');
}
return;
}
ratio++;
blobs[order] = blob;
errors
? resetDownloadIcon()
: updateProgress(Math.round(100 * ratio / blobs.length));
store();
};
// 保存视频文件
function store() {
for (let [index, blob] of blobs.entries()) {
if (blob == undefined) return;
}
let blob = new Blob(blobs, {type: 'video/h264'}),
filename = (new Date()).valueOf() + '.mp4',
url = window.URL.createObjectURL(blob),
userAgent = window.navigator.userAgent;
blobs = null;
// 结束进度显示
resetDownloadIcon();
// edge
if (window.navigator && window.navigator.msSaveBlob) {
window.navigator.msSaveBlob(blob, filename);
}
else {
url = window.URL.createObjectURL(blob);
// Chrome 可以使用 Tampermonkey 的 GM_download 函数绕过 CSP(Content Security Policy) 的限制
if (userAgent.indexOf('Chrome') > 0 && window.GM_download) {
GM_download(url, filename);
}
else {
// firefox 需要禁用 CSP, about:config -> security.csp.enable => false
// violentmonkey(暴力猴)没有 GM_download 函数
var a = document.createElement('a');
document.body.appendChild(a);
a.href = url;
a.download = filename;
//a.target = '_blank';
a.click();
document.body.removeChild(a);
setTimeout(function () {
window.URL.revokeObjectURL(url);
}, 100);
}
}
};
// 重置下载图标
function resetDownloadIcon() {
domDownloadBtn.querySelector('svg').innerHTML = svgDownload;
};
// 更新下载进度界面
function updateProgress(percent) {
let r = 8;
let degrees = percent / 100 * 360; // 进度对应的角度值
let rad = degrees * (Math.PI / 180); // 角度对应的弧度值
let x = (Math.sin(rad) * r).toFixed(2); // 极坐标转换成直角坐标
let y = -(Math.cos(rad) * r).toFixed(2);
let lenghty = Number(degrees > 180); // 大于180°时画大角度弧，小于180°时画小角度弧，(deg > 180) ? 1 : 0
let paths = ['M', 0, -r, 'A', r, r, 0, lenghty, 1, x, y]; // path 属性
domDownloadBtn.querySelector('svg > path').setAttribute('d', paths.join(' '));
domDownloadBtn.querySelector('svg > text').textContent = percent;
};
//await wait(500);
// 读取 playlist
const res = await fetchRetry(playlistBaseUrl + videoId, {
headers: {
'referer': 'refererBaseUrl + videoId',
'authorization': 'oauth c3cef7c66a1843f8b3a9e6a1e3160e20' // in zplayer.min.js of zhihu
}
}, 3);
const videoInfo = await res.json();
// 获取不同分辨率视频的信息
for (let [key, video] of Object.entries(videoInfo.playlist)) {
video.name = key;
videos.push(video);
}
// 按分辨率大小排序
videos = videos.sort(function (v1, v2) {
return v1.width == v2.width ? 0 : (v1.width > v2.width ? 1 : -1);
}).reverse();
// 生成下载按钮图标
domDownloadBtn.querySelector('button:first-child').outerHTML = domFullScreenBtn.cloneNode(true).querySelector('button').outerHTML;
domDownloadBtn.querySelector('svg').innerHTML = svgDownload;
// 生成各分辨率菜单
domMenuItem.className = domMenuItem.className.split('-').shift();
domMenuItem.parentNode.innerHTML = '';
for (let [index, video] of videos.entries()) {
let node = domMenuItem.cloneNode();
node.innerHTML = video.width + ' (' + fileSize(video.size) + ')';
node.style.width = '100%';
node.style.textAlign = 'right';
node.dataset.videoIndex = index;
domMenu.appendChild(node);
}
// 鼠标事件 - 显示菜单
domDownloadBtn.addEventListener('pointerenter', () => {
if (blobs == null) {
domMenu.parentNode.style.cssText = menuStyle + 'opacity:1 !important; visibility:visible !important';
}
});
// 鼠标事件 - 隐藏菜单
domDownloadBtn.addEventListener('pointerleave', () => {
if (blobs == null) {
domMenu.parentNode.style.cssText = menuStyle;
}
});
// 鼠标事件 - 暂停下载
// domDownloadBtn.addEventListener('pointerdown', () => {});
// 鼠标事件 - 选择菜单项
domDownloadBtn.addEventListener('pointerup', event => {
let e = event.srcElement || event.target;
let video;
if (e.tagName == 'BUTTON' && !e.children.length) {
video = videos[e.dataset.videoIndex];
// 隐藏菜单
domMenu.dispatchEvent(new MouseEvent('pointerleave', {
'bubbles': true,
'cancelable': true
}));
downloadM3u8(video.play_url);
}
});
// 显示下载按钮
domControlBar.appendChild(domDownloadBtn);
})();