Youtube Subtitle Downloader v22

Download Subtitles
当前为 2020-12-03 提交的版本，查看最新版本。
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// ==UserScript==
// @name           Youtube Subtitle Downloader v22
// @include        https://*youtube.com/*
// @author         Cheng Zheng
// @copyright      2009 Tim Smart; 2011 gw111zz; 2014~2021 Cheng Zheng;
// @license        GNU GPL v3.0 or later. http://www.gnu.org/copyleft/gpl.html
// @require        http://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js
// @version        22
// @grant GM_xmlhttpRequest
// @namespace https://greasyfork.org/users/5711
// @description   Download Subtitles
// ==/UserScript==
 
/*
  [What is this?]
  This "Tampermonkey script" allow you download Youtube "Automatic subtitle" and "closed subtitle"
 
  [Note]
  If it doesn't work(rarely), try refresh.
  if problem still exist. Email: guokrfans@gmail.com
 
  [Who build this]
  Author :  Cheng Zheng
  Email  :  guokrfans@gmail.com
  Github :  https://github.com/1c7/Youtube-Auto-Subtitle-Download
  If you want improve the script, Github Pull Request are welcome
 
  [Note]
  Few things before you read the code:
  0. Some code comments are written in Chinese
  1. Youtube have 2 UI: Material design and The old design
  2. Code need handle both Auto & Closed subtitle
 
  (Explain: "Tampermonkey script" mean
  you have to install a Chrome extension call "Tampermonkey", and then install this script)
 
  [Test Video]
  https://www.youtube.com/watch?v=bkVsus8Ehxs
  only have English closed subtitle, nothing else (no auto subtitle)
 
  https://www.youtube.com/watch?v=-WEqFzyrbbs
  no subtitle at all
 
  https://www.youtube.com/watch?v=9AzNEG1GB-k
  have a lot subtitle 
 
  https://www.youtube.com/watch?v=tqGkOvrKGfY
  1:36:33  super long subtitle
 
  [Code Explain]
  mainly three part
    1. UI specific (add button on page etc)
    2. detech if subtitle exists
    3. transform subtitle format & download
 
   [Changelog]
    v1~v15: I forgot, and I am too lazy to check git log
 
    v16: add support for auto subtitle
 
    v17: fix few minor issue in v16, to make sure all user get update, bump up 1 version
 
    v18: fix https://greasyfork.org/zh-CN/forum/discussion/38299/x?locale=zh-CN  video too long issue
    (for example 1:36:33) and cause subtitle error
    reason is the 'downloadFile' function 
    using a <a> element 'href' attribute to download .srt file.
    and this 'href' can't handle string that's too long
 
    v19: fix HTML html entity problem, for example: apostrophe as &#39;
 
    v20: 2018-June-13 seem like Youtube change their URL format, now URL must have something like '&name=en'
     v20 test with: https://www.youtube.com/watch?v=tqGkOvrKGfY  https://www.youtube.com/watch?time_continue=5&v=36tggrpRoTI
 
    v21&v22: improve code logic
*/
 
(function () {
 
  // Config
  var NO_SUBTITLE = 'No Subtitle';
  var HAVE_SUBTITLE = 'Download Subtitles';
  const BUTTON_ID = 'youtube-subtitle-downloader-by-1c7-last-update-2020-12-3'
  // Config
 
  var HASH_BUTTON_ID = `#${BUTTON_ID}`
 
  // initialize
  var first_load = true; // indicate if first load this webpage or not
  var youtube_playerResponse_1c7 = null; // for auto subtitle
  unsafeWindow.caption_array = []; // store all subtitle
 
  // trigger when first load
  $(document).ready(function () {
    start();
  });
 
  // Explain this function: we repeatly try if certain HTML element exist, 
  // if it does, we call init()
  // if it doesn't, stop trying after certain time
  function start() {
    var retry_count = 0;
    var RETRY_LIMIT = 20;
    // use "setInterval" is because "$(document).ready()" still not enough, still too early
    // 330 work for me.
    if (new_material_design_version()) {
      var material_checkExist = setInterval(function () {
        if (document.querySelectorAll('.title.style-scope.ytd-video-primary-info-renderer').length) {
          init();
          clearInterval(material_checkExist);
        }
        retry_count = retry_count + 1;
        if (retry_count > RETRY_LIMIT) {
          clearInterval(material_checkExist);
        }
      }, 330);
    } else {
      var checkExist = setInterval(function () {
        if ($('#watch7-headline').length) {
          init();
          clearInterval(checkExist);
        }
        retry_count = retry_count + 1;
        if (retry_count > RETRY_LIMIT) {
          clearInterval(checkExist);
        }
      }, 330);
    }
  }
 
  // trigger when loading new page 
  // (actually this would also trigger when first loading, that's not what we want, that's why we need to use firsr_load === false)
  // (new Material design version would trigger this "yt-navigate-finish" event. old version would not.)
  var body = document.getElementsByTagName("body")[0];
  body.addEventListener("yt-navigate-finish", function (event) {
    if (current_page_is_video_page() === false) {
      return;
    }
    youtube_playerResponse_1c7 = event.detail.response.playerResponse; // for auto subtitle
    unsafeWindow.caption_array = []; // clean up (important, otherwise would have more and more item and cause error)
 
    // if use click to another page, init again to get correct subtitle
    if (first_load === false) {
      remove_subtitle_download_button();
      init();
    }
  });
 
  // trigger when loading new page
  // (old version would trigger "spfdone" event. new Material design version not sure yet.)
  window.addEventListener("spfdone", function (e) {
    if (current_page_is_video_page()) {
      remove_subtitle_download_button();
      var checkExist = setInterval(function () {
        if ($('#watch7-headline').length) {
          init();
          clearInterval(checkExist);
        }
      }, 330);
    }
  });
 
  // return true / false
  // Detect [new version UI(material design)] OR [old version UI]
  // I tested this, accurated.
  function new_material_design_version() {
    var old_title_element = document.getElementById('watch7-headline');
    if (old_title_element) {
      return false;
    } else {
      return true;
    }
  }
 
  // return true / false
  function current_page_is_video_page() {
    return get_video_id() !== null;
  }
 
  // return string like "RW1ChiWyiZQ",  from "https://www.youtube.com/watch?v=RW1ChiWyiZQ"
  // or null
  function get_video_id() {
    return getURLParameter('v');
  }
 
  //https://stackoverflow.com/questions/11582512/how-to-get-url-parameters-with-javascript/11582513#11582513
  function getURLParameter(name) {
    return decodeURIComponent((new RegExp('[?|&]' + name + '=' + '([^&;]+?)(&|#|;|$)').exec(location.search) || [null, ''])[1].replace(/\+/g, '%20')) || null;
  }
 
  function remove_subtitle_download_button() {
    $(HASH_BUTTON_ID).remove();
  }
 
  function init() {
    inject_our_script();
    first_load = false;
  }
 
  function inject_our_script() {
    var div = document.createElement('div'),
      select = document.createElement('select'),
      option = document.createElement('option'),
      controls = document.getElementById('watch7-headline'); // Youtube video title DIV
 
    div.setAttribute('style', `display: table; 
margin-top:4px;
border: 1px solid rgb(0, 183, 90); 
cursor: pointer; color: rgb(255, 255, 255); 
border-top-left-radius: 3px; 
border-top-right-radius: 3px; 
border-bottom-right-radius: 3px; 
border-bottom-left-radius: 3px; 
background-color: #00B75A;
`);
 
    div.id = BUTTON_ID;
    div.title = 'Youtube Subtitle Download v16'; // display when cursor hover
 
    select.id = 'captions_selector';
    select.disabled = true;
    select.setAttribute('style', `display:block; 
border: 1px solid rgb(0, 183, 90); 
cursor: pointer; 
color: rgb(255, 255, 255); 
background-color: #00B75A;
padding: 4px;
`);
 
    option.textContent = 'Loading...';
    option.selected = true;
    select.appendChild(option);
 
    // 下拉菜单里，选择一项后触发下载
    select.addEventListener('change', function () {
      download_subtitle(this);
    }, false);
 
    div.appendChild(select); // put <select> into <div>
 
    // put the div into page: new material design
    var title_element = document.querySelectorAll('.title.style-scope.ytd-video-primary-info-renderer');
    if (title_element) {
      $(title_element[0]).after(div);
    }
    // put the div into page: old version
    if (controls) {
      controls.appendChild(div);
    }
 
    load_language_list(select);
 
    // <a> element is for download
    var a = document.createElement('a');
    a.style.cssText = 'display:none;';
    a.setAttribute("id", "ForSubtitleDownload");
    var body = document.getElementsByTagName('body')[0];
    body.appendChild(a);
  }
 
  // trigger when user select <option>
  function download_subtitle(selector) {
    // if user select first <option>
    // we just return, do nothing.
    if (selector.selectedIndex == 0) {
      return;
    }
 
    var caption = caption_array[selector.selectedIndex - 1];
    // because first <option> is for display
    // so index - 1 
 
    // if user choose auto subtitle
    if (caption.lang_code == 'AUTO') {
      get_auto_subtitle(function (r) {
        if (r != false) {
          var srt = parse_youtube_XML_to_SRT(r);
          var title = get_file_name('auto');
          downloadString(srt, "text/plain", title);
        }
      });
    } else {
      // closed subtitle
      var lang_code = caption.lang_code;
      var lang_name = caption.lang_name;
      get_closed_subtitle(lang_code, function (r) {
        if (r != false) {
          var srt = parse_youtube_XML_to_SRT(r);
          var title = get_file_name(lang_name);
          downloadString(srt, "text/plain", title);
        }
      });
    }
    // after download, select first <option>
    selector.options[0].selected = true;
  }
 
 
  // Return something like: "(English)How Did Python Become A Data Science Powerhouse?.srt"
  function get_file_name(x) {
    return '(' + x + ')' + document.title + '.srt';
  }
 
  // detect if "auto subtitle" and "closed subtitle" exist
  // and add <option> into <select>
  function load_language_list(select) {
    // auto
    var auto_subtitle_exist = false;
 
    // closed
    var closed_subtitle_exist = false;
    var captions = null;
 
    // get auto subtitle
    var auto_subtitle_url = get_auto_subtitle_xml_url();
    if (auto_subtitle_url != false) {
      auto_subtitle_exist = true;
    }
 
    // get closed subtitle
    var list_url = 'https://video.google.com/timedtext?hl=en&v=' + get_video_id() + '&type=list';
    // Example: https://video.google.com/timedtext?hl=en&v=if36bqHypqk&type=list
    GM_xmlhttpRequest({
      method: 'GET',
      url: list_url,
      onload: function (xhr) {
        captions = new DOMParser().parseFromString(xhr.responseText, "text/xml").getElementsByTagName('track');
        if (captions.length != 0) {
          closed_subtitle_exist = true;
        }
 
        // if no subtitle at all, just say no and stop
        if (auto_subtitle_exist == false && closed_subtitle_exist == false) {
          select.options[0].textContent = NO_SUBTITLE;
          disable_download_button();
          return false;
        }
 
        // if at least one type of subtitle exist
        select.options[0].textContent = HAVE_SUBTITLE;
        select.disabled = false;
 
        var caption = null; // for inside loop
        var option = null; // for <option>
        var caption_info = null; // for our custom object
 
        // if auto subtitle exist
        if (auto_subtitle_exist) {
          caption_info = {
            lang_code: 'AUTO', // later we use this to know if it's auto subtitle
            lang_name: get_auto_subtitle_name() // for display only
          };
          caption_array.push(caption_info);
 
          option = document.createElement('option');
          option.textContent = caption_info.lang_name;
          select.appendChild(option);
        }
 
        // if closed_subtitle_exist
        if (closed_subtitle_exist) {
          for (var i = 0, il = captions.length; i < il; i++) {
            caption = captions[i];
            caption_info = {
              lang_code: caption.getAttribute('lang_code'), // for AJAX request
              lang_name: caption.getAttribute('lang_translated') // for display only
            };
            caption_array.push(caption_info);
            // 注意这里是加到 caption_array, 一个全局变量, 待会要靠它来下载
            option = document.createElement('option');
            option.textContent = caption_info.lang_name;
            select.appendChild(option);
          }
        }
      }
    });
  }
 
  function disable_download_button() {
    $(HASH_BUTTON_ID)
      .css('border', '#95a5a6')
      .css('cursor', 'not-allowed')
      .css('background-color', '#95a5a6');
    $('#captions_selector')
      .css('border', '#95a5a6')
      .css('cursor', 'not-allowed')
      .css('background-color', '#95a5a6');
 
    if (new_material_design_version()) {
      $(HASH_BUTTON_ID).css('padding', '6px');
    } else {
      $(HASH_BUTTON_ID).css('padding', '5px');
    }
  }
 
  // 处理时间. 比如 start="671.33"  start="37.64"  start="12" start="23.029"
  // 处理成 srt 时间, 比如 00:00:00,090    00:00:08,460    00:10:29,350
  function process_time(s) {
    s = s.toFixed(3);
    // 超棒的函数, 不论是整数还是小数都给弄成3位小数形式
    // 举个柚子:
    // 671.33 -> 671.330
    // 671 -> 671.000
    // 注意函数会四舍五入. 具体读文档
 
    var array = s.split('.');
    // 把开始时间根据句号分割
    // 671.330 会分割成数组: [671, 330]
 
    var Hour = 0;
    var Minute = 0;
    var Second = array[0]; // 671
    var MilliSecond = array[1]; // 330
    // 先声明下变量, 待会把这几个拼好就行了
 
    // 我们来处理秒数.  把"分钟"和"小时"除出来
    if (Second >= 60) {
      Minute = Math.floor(Second / 60);
      Second = Second - Minute * 60;
      // 把 秒 拆成 分钟和秒, 比如121秒, 拆成2分钟1秒
 
      Hour = Math.floor(Minute / 60);
      Minute = Minute - Hour * 60;
      // 把 分钟 拆成 小时和分钟, 比如700分钟, 拆成11小时40分钟
    }
    // 分钟，如果位数不够两位就变成两位，下面两个if语句的作用也是一样。
    if (Minute < 10) {
      Minute = '0' + Minute;
    }
    // 小时
    if (Hour < 10) {
      Hour = '0' + Hour;
    }
    // 秒
    if (Second < 10) {
      Second = '0' + Second;
    }
    return Hour + ':' + Minute + ':' + Second + ',' + MilliSecond;
  }
 
  // copy from: https://gist.github.com/danallison/3ec9d5314788b337b682
  // Thanks! https://github.com/danallison
  // work in Chrome 66
  // test passed: 2018-5-19
  function downloadString(text, fileType, fileName) {
    var blob = new Blob([text], {
      type: fileType
    });
    var a = document.createElement('a');
    a.download = fileName;
    a.href = URL.createObjectURL(blob);
    a.dataset.downloadurl = [fileType, a.download, a.href].join(':');
    a.style.display = "none";
    document.body.appendChild(a);
    a.click();
    document.body.removeChild(a);
    setTimeout(function () {
      URL.revokeObjectURL(a.href);
    }, 1500);
  }
 
  // https://css-tricks.com/snippets/javascript/unescape-html-in-js/
  // turn HTML entity back to text, example: &quot; should be "
  function htmlDecode(input) {
    var e = document.createElement('div');
    e.class = 'dummy-element-for-tampermonkey-Youtube-Subtitle-Downloader-script-to-decode-html-entity';
    e.innerHTML = input;
    return e.childNodes.length === 0 ? "" : e.childNodes[0].nodeValue;
  }
 
  // return URL or null;
  // later we can send a AJAX and get XML subtitle
  function get_auto_subtitle_xml_url() {
    try {
      var captionTracks = get_captionTracks()
      for (var index in captionTracks) {
        var caption = captionTracks[index];
        if (typeof caption.kind === 'string' && caption.kind == 'asr') {
          return captionTracks[index].baseUrl;
        }
        // ASR – A caption track generated using automatic speech recognition.
        // https://developers.google.com/youtube/v3/docs/captions
      }
      return false;
    } catch (error) {
      return false;
    }
  }
 
  function get_auto_subtitle(callback) {
    var url = get_auto_subtitle_xml_url();
    get_from_url(url, callback);
  }
 
  function get_closed_subtitle(lang_code, callback) {
    try {
      var captionTracks = get_captionTracks()
      for (var index in captionTracks) {
        var caption = captionTracks[index];
        if (caption.languageCode === lang_code && caption.kind != 'asr') {
          // 必须写 caption.kind != 'asr'
          // 否则会下载2个字幕文件（也就是这个分支会进来2次）
          // 因为 lang_code 是 "en" 会 match 2条纪录，一条是自动字幕，一条是完整字幕
          // 自动字幕那条是 kind=asr
          // 完成字幕那条没有 kind 属性
          var url = captionTracks[index].baseUrl;
          get_from_url(url, callback);
        }
      }
      return false;
    } catch (error) {
      return false;
    }
 
  }
 
  function get_from_url(url, callback) {
    $.ajax({
      url: url,
      type: 'get',
      success: function (r) {
        callback(r);
      },
      fail: function (error) {
        callback(false);
      }
    });
  }
 
  // Youtube return XML. we want SRT  
  // input: Youtube XML format
  // output: SRT format
  function parse_youtube_XML_to_SRT(youtube_xml_string) {
    if (youtube_xml_string === '') {
      return false;
    }
    var text = youtube_xml_string.getElementsByTagName('text');
    var result = '';
    var BOM = '\uFEFF';
    result = BOM + result; // store final SRT result
    var len = text.length;
    for (var i = 0; i < len; i++) {
      var index = i + 1;
      var content = text[i].textContent.toString();
      content = content.replace(/(<([^>]+)>)/ig, ""); // remove all html tag.
      var start = text[i].getAttribute('start');
      var end = parseFloat(text[i].getAttribute('start')) + parseFloat(text[i].getAttribute('dur'));
 
      // if (i + 1 >= len) {
      //   end = parseFloat(text[i].getAttribute('start')) + parseFloat(text[i].getAttribute('dur'));
      // } else {
      //   end = text[i + 1].getAttribute('start');
      // }
 
      // we want SRT format:
      /*
          1
          00:00:01,939 --> 00:00:04,350
          everybody Craig Adams here I'm a
 
          2
          00:00:04,350 --> 00:00:06,720
          filmmaker on YouTube who's digging
      */
      var new_line = "\n";
      result = result + index + new_line;
      // 1
 
      var start_time = process_time(parseFloat(start));
      var end_time = process_time(parseFloat(end));
      result = result + start_time;
      result = result + ' --> ';
      result = result + end_time + new_line;
      // 00:00:01,939 --> 00:00:04,350
 
      content = htmlDecode(content);
      // turn HTML entity back to text. example: &#39; back to apostrophe (')
 
      result = result + content + new_line + new_line;
      // everybody Craig Adams here I'm a
    }
    return result;
  }
 
  // return "English (auto-generated)" or a default name;
  function get_auto_subtitle_name() {
    try {
      var json = get_json();
      if (typeof json.captions !== "undefined") {
        var captionTracks = json.captions.playerCaptionsTracklistRenderer.captionTracks;
        for (var index in captionTracks) {
          var caption = captionTracks[index];
          if (typeof caption.kind === 'string' && caption.kind == 'asr') {
            return captionTracks[index].name.simpleText;
          }
        }
      }
      return 'Auto Subtitle';
    } catch (error) {
      return 'Auto Subtitle';
    }
  }
 
  // return player_response
  // or return null
  function get_json() {
    try {
      var json = null
      if (typeof youtube_playerResponse_1c7 !== "undefined" && youtube_playerResponse_1c7 !== null && youtube_playerResponse_1c7 !== '') {
        json = youtube_playerResponse_1c7;
      }
      if (ytplayer.config.args.player_response) {
        var raw_string = ytplayer.config.args.player_response;
        json = JSON.parse(raw_string);
      }
      if (ytplayer.config.args.raw_player_response) {
        json = ytplayer.config.args.raw_player_response;
      }
      return json
    } catch (error) {
      return null
    }
  }
 
  function get_captionTracks() {
    var json = get_json();
    var captionTracks = json.captions.playerCaptionsTracklistRenderer.captionTracks;
    return captionTracks
  }
 
})();