哔哩哔哩弹幕姬.js

// ==UserScript==
// @name		bilibiliDanmaku
// @name:zh-CN	哔哩哔哩弹幕姬
// @namespace	https://github.com/sakuyaa/gm_scripts
// @author		sakuyaa
// @description	在哔哩哔哩视频标题下方增加弹幕查看和下载
// @include		http*://www.bilibili.com/video/av*
// @include		http*://www.bilibili.com/video/BV*
// @include		http*://www.bilibili.com/watchlater/#/av*
// @include		http*://www.bilibili.com/watchlater/#/BV*
// @include		http*://www.bilibili.com/medialist/play/*/*
// @include		http*://www.bilibili.com/bangumi/play/*
// @version		2020.11.1
// @compatible	firefox 52
// @grant		none
// @run-at		document-end
// ==/UserScript==
(function () {
  let view, download, downloadAll, downloadPast, subSpan, downloadSub, convertSub;

  //拦截pushState和replaceState事件
  let historyFunc = type => {
    let origin = history[type];
    return function () {
      let e = new Event(type);
      e.arguments = arguments;
      window.dispatchEvent(e);
      return origin.apply(history, arguments);
    };
  };
  history.pushState = historyFunc('pushState');
  history.replaceState = historyFunc('replaceState');

  let sleep = time => {
    return new Promise(resolve => setTimeout(resolve, time));
  };
  let fetchFunc = (url, type) => {
    let init = {};
    if (url.indexOf('.bilibili.com/') > 0) {
      init.credentials = 'include';
    }
    return fetch(url, init).then(response => {
      if (!response.ok) {
        throw new Error(`bilibiliDanmaku：${response.status} ${response.statusText}\n无法加载：${url}`);
      }
      switch (type) {
        case 'blob':
          return response.blob();
        case 'json':
          return response.json();
        default:
          return response.text();
      }
    });
  };
  //获取视频发布日期
  let fetchPubDate = async () => {
    let response = await fetchFunc(`https://api.bilibili.com/x/web-interface/view?${window.bvid ? 'bvid=' + window.bvid : 'aid=' + window.aid}`, 'json');
    if (response.data.pubdate) {
      let pubDate = new Date(response.data.pubdate * 1000);
      if (!isNaN(pubDate)) {
        return pubDate;
      }
    }
    return null;
  };
  //获取CC字幕列表
  let fetchSubtitles = async () => {
    let response = await fetchFunc(`https://api.bilibili.com/x/web-interface/view?${window.bvid ? 'bvid=' + window.bvid : 'aid=' + window.aid}`, 'json');
    if (response.data.subtitle.list) {
      return response.data.subtitle.list;
    }
    return [];
  };
  //秒转化为时分秒
  let formatSeconds = seconds => {
    let h = Math.floor(seconds / 3600);
    if (h < 10) {
      h = '0' + h;
    }
    let m = Math.floor((seconds / 60 % 60));
    if (m < 10) {
      m = '0' + m;
    }
    let s = Math.floor((seconds % 60));
    if (s < 10) {
      s = '0' + s;
    }
    let ms = '00' + Math.floor(seconds * 1000 % 1000);
    return `${h}:${m}:${s}.${ms.substr(-3)}`;
  }

  let danmakuFunc = async () => {
    //查看弹幕
    view.setAttribute('href', `https://comment.bilibili.com/${window.cid}.xml`);
    //下载弹幕
    download.removeAttribute('download');
    download.setAttribute('href', 'javascript:;');
    download.onclick = async () => {
      let danmaku = await fetchFunc(`https://api.bilibili.com/x/v1/dm/list.so?oid=${window.cid}&bilibiliDanmaku=1`, 'blob');
      download.onclick = null;
      download.setAttribute('download', document.title.split('_')[0] + '.xml');
      download.setAttribute('href', URL.createObjectURL(danmaku));
      download.dispatchEvent(new MouseEvent('click'));
    };
    //全弹幕下载
    downloadAll.removeAttribute('download');
    downloadAll.setAttribute('href', 'javascript:;');
    downloadAll.onclick = async () => {
      try {
        //加载当前弹幕池
        let danmakuMap = new Map();
        let danmaku = await fetchFunc(`https://api.bilibili.com/x/v1/dm/list.so?oid=${window.cid}&bilibiliDanmaku=1`);
        let danmakuAll = danmaku.substring(0, danmaku.indexOf('<d p='));
        let exp = new RegExp('<d p="([^,]+)[^"]+,(\\d+)">.+?</d>', 'g');
        while ((match = exp.exec(danmaku)) != null) {
          danmakuMap.set(parseInt(match[2]), [parseFloat(match[1]), match[0]]);
        }
        //获取视频发布日期
        let now = new Date();
        let pubDate, year, month;
        let dateNode = document.querySelector('.video-data span:nth-child(2)');
        if (dateNode) {
          pubDate = new Date(dateNode.textContent);
          if (isNaN(pubDate)) {
            pubDate = await fetchPubDate();
          }
        } else {
          pubDate = await fetchPubDate();
        }
        if (!pubDate) {
          alert('获取视频投稿时间失败！');
          return;
        }
        year = pubDate.getFullYear();
        month = pubDate.getMonth() + 1;
        //计算历史月份
        let monthArray = [];
        while (year * 100 + month <= now.getFullYear() * 100 + now.getMonth() + 1) {
          monthArray.push(`https://api.bilibili.com/x/v2/dm/history/index?type=1&oid=${window.cid}&month=${year + '-' + ('0' + month).substr(-2)}`);
          if (++month > 12) {
            month = 1;
            year++;
          }
        }
        //增加延迟
        let delay;
        if ((delay = prompt('由于网站弹幕接口改版新的API限制获取速度，全弹幕下载需要有获取间隔，会导致该功能需要很长很长时间进行弹幕获取（视投稿时间而定，每天都有历史数据的话获取一个月大概需要20多秒），请输入获取间隔（若仍出现获取速度过快请适当加大间隔，单位：毫秒）', 299)) == null) {
          return;
        }
        if (isNaN(delay)) {
          alert('输入值不是数值！');
          return;
        }
        //进度条
        let progress = document.createElement('progress');
        progress.setAttribute('max', monthArray.length * 1000);
        progress.setAttribute('value', 0);
        progress.style.position = 'fixed';
        progress.style.margin = 'auto';
        progress.style.left = progress.style.right = 0;
        progress.style.top = progress.style.bottom = 0;
        progress.style.zIndex = 99;   //进度条置顶
        document.body.appendChild(progress);
        //获取历史弹幕日期
        let data;
        for (let i = 0; i < monthArray.length;) {
          data = await fetchFunc(monthArray[i], 'json');
          if (data.code) {
            throw new Error('bilibiliDanmaku，API接口返回错误：' + data.message);
          }
          if (data.data) {
            for (let j = 0; j < data.data.length; j++) {
              progress.setAttribute('value', i * 1000 + 1000 / data.data.length * j);
              await sleep(delay);   //避免网站API调用速度过快导致错误
              danmaku = await fetchFunc(`https://api.bilibili.com/x/v2/dm/history?type=1&oid=${window.cid}&date=${data.data[j]}&bilibiliDanmaku=1`);
              if ((match = (new RegExp('^\{"code":[^,]+,"message":"([^"]+)","ttl":[^\}]+\}$',)).exec(danmaku)) != null) {
                throw new Error('bilibiliDanmaku，API接口返回错误：' + match[1]);
              }
              exp = new RegExp('<d p="([^,]+)[^"]+,(\\d+)">.+?</d>', 'g');
              while ((match = exp.exec(danmaku)) != null) {
                if (!danmakuMap.has(parseInt(match[2]))) {   //跳过重复的项目
                  danmakuMap.set(parseInt(match[2]), [parseFloat(match[1]), match[0]]);
                }
              }
            }
          }
          progress.setAttribute('value', ++i * 1000);
        }
        //按弹幕播放时间排序
        let danmakuArray = [];
        for (let value of danmakuMap.values()) {
          danmakuArray.push(value);
        }
        danmakuArray.sort((a, b) => a[0] - b[0]);
        //合成弹幕
        document.body.removeChild(progress);
        for (let pair of danmakuArray) {
          danmakuAll += pair[1];
        }
        danmakuAll += '</i>';
        //设置下载链接
        downloadAll.onclick = null;
        downloadAll.setAttribute('download', document.title.split('_')[0] + '.xml');
        downloadAll.setAttribute('href', URL.createObjectURL(new Blob([danmakuAll])));
        downloadAll.dispatchEvent(new MouseEvent('click'));
      } catch (e) {
        alert(e);
      }
    };
    //历史弹幕下载
    downloadPast.onclick = async () => {
      //获取视频发布日期
      let date;
      let dateNode = document.querySelector('.video-data span:nth-child(2)');
      if (dateNode) {
        date = new Date(dateNode.textContent);
        if (isNaN(date)) {
          date = await fetchPubDate();
        }
      } else {
        date = await fetchPubDate();
      }
      if (!date) {   //获取视频投稿时间失败，默认设置为当天
        date = new Date();
      }
      if ((date = prompt('请按此格式输入想要下载历史弹幕的日期', date.getFullYear() + '-' + ('0' + (date.getMonth() + 1)).substr(-2) + '-' + ('0' + date.getDate()).substr(-2))) == null) {
        return;
      }
      let danmaku = await fetchFunc(`https://api.bilibili.com/x/v2/dm/history?type=1&oid=${window.cid}&date=${date}&bilibiliDanmaku=1`);
      let aLink = document.createElement('a');
      aLink.setAttribute('download', document.title.split('_')[0] + '_' + date + '.xml');
      aLink.setAttribute('href', URL.createObjectURL(new Blob([danmaku])));
      aLink.dispatchEvent(new MouseEvent('click'));
    };

    //获取CC字幕列表
    let subList = [];
    let notFound = true;
    if (window.eventLogText) {
      for (let i = window.eventLogText.length - 1; i >= 0; i--) {
        let eventLog = window.eventLogText[i];
        if (eventLog.indexOf('<subtitle>') > 0) {
          notFound = false;
          try {
            subList = JSON.parse(eventLog.substring(eventLog.indexOf('<subtitle>') + 10,
              eventLog.indexOf('</subtitle>'))).subtitles;
          } catch (e) {
            console.log(e);
            notFound = true;
          }
          break;
        }
      }
    }
    if (notFound) {
      subList = await fetchSubtitles();
    }
    if (subList.length == 0) {   //没有CC字幕则隐藏相关按钮
      subSpan.setAttribute('hidden', 'hidden');
      downloadSub.onclick = null;
      convertSub.onclick = null;
      return;
    } else {
      subSpan.removeAttribute('hidden');
    }
    //下载CC字幕
    downloadSub.onclick = async () => {
      let aLink = document.createElement('a');
      for (let sub of subList) {
        let subtitle = await fetchFunc(sub.subtitle_url.replace(/^http:/, ''), 'blob');   //避免混合内容
        aLink.setAttribute('download', sub.lan + '_' + document.title.split('_')[0] + '.json');
        aLink.setAttribute('href', URL.createObjectURL(subtitle));
        aLink.dispatchEvent(new MouseEvent('click'));
      }
    };
    //生成SRT字幕
    convertSub.onclick = async () => {
      let aLink = document.createElement('a');
      for (let sub of subList) {
        let subtitle = await fetchFunc(sub.subtitle_url.replace(/^http:/, ''), 'json');   //避免混合内容
        let srt = '', index = 0;
        for (let content of subtitle.body) {
          srt += `${index++}\n${formatSeconds(content.from)} --> ${formatSeconds(content.to)}\n${content.content.replace(/\n/g, '<br>')}\n\n`;
        }
        aLink.setAttribute('download', sub.lan + '_' + document.title.split('_')[0] + '.srt');
        aLink.setAttribute('href', URL.createObjectURL(new Blob([srt])));
        aLink.dispatchEvent(new MouseEvent('click'));
      }
    };
  };

  let findInsertPos = () => {
    let node;
    if (location.href.indexOf('www.bilibili.com/bangumi/play') > 0) {   //番剧
      node = document.querySelector('.media-right');
      if (node && node.querySelector('.media-count').textContent.indexOf('弹幕') == -1) {
        return null;   //避免信息栏未加载出来时插入链接导致错误
      }
    } else if (location.href.indexOf('www.bilibili.com/watchlater') > 0) {   //稍后再看
      node = document.querySelector('.tminfo');
      if (node) {
        node.lastElementChild.style.marginRight = '32px';
      }
    } else if (location.href.indexOf('www.bilibili.com/medialist/play') > 0) {   //新的稍后再看页面、收藏页面
      node = document.querySelector('.play-data');
      if (node) {
        node.lastElementChild.style.marginRight = '16px';
      }
      //新的稍后再看页面没有aid、bvid、cid，需要特殊处理
      let videoMessage = window.player.getVideoMessage();
      if (videoMessage) {
        window.aid = videoMessage.aid;
        window.cid = videoMessage.cid;
      } else {
        return null;
      }
    } else {
      node = document.getElementById('viewbox_report');
      if (node) {
        if (!document.querySelector('.bilibili-player-video-info-people-number')) {
          return null;   //避免信息栏未加载出来时插入链接导致错误
        }
        node = node.querySelector('.video-data');
        node.lastElementChild.style.marginRight = '16px';
      }
    }
    return node;
  };
  let createNode = () => {
    view = document.createElement('a');
    download = document.createElement('a');
    downloadAll = document.createElement('a');
    downloadPast = document.createElement('a');
    downloadSub = document.createElement('a');
    convertSub = document.createElement('a');
    view.setAttribute('target', '_blank');
    downloadPast.setAttribute('href', 'javascript:;');
    downloadSub.setAttribute('href', 'javascript:;');
    convertSub.setAttribute('href', 'javascript:;');
    view.textContent = '查看弹幕';
    download.textContent = '下载弹幕';
    downloadAll.textContent = '全弹幕下载';
    downloadPast.textContent = '历史弹幕下载';
    downloadSub.textContent = '下载CC字幕';
    convertSub.textContent = '生成SRT字幕';
    view.style.color = '#999';
    download.style.color = '#999';
    downloadAll.style.color = '#999';
    downloadPast.style.color = '#999';
    downloadSub.style.color = '#999';
    convertSub.style.color = '#999';
    let span = document.createElement('span');
    span.id = 'bilibiliDanmaku';
    span.appendChild(view);
    span.appendChild(document.createTextNode(' | '));
    span.appendChild(download);
    span.appendChild(document.createTextNode(' | '));
    span.appendChild(downloadAll);
    span.appendChild(document.createTextNode(' | '));
    span.appendChild(downloadPast);
    subSpan = document.createElement('span');
    subSpan.setAttribute('hidden', 'hidden');
    subSpan.style.marginLeft = '16px';   //弹幕与字幕功能分开
    subSpan.appendChild(downloadSub);
    subSpan.appendChild(document.createTextNode(' | '));
    subSpan.appendChild(convertSub);
    span.appendChild(subSpan);
    return span;
  };
  let insertNode = () => {
    let code = setInterval(() => {
      if (location.href.indexOf('www.bilibili.com/medialist/play') > 0) {
        if (!window.player) {   //新的稍后再看页面、收藏页面没有cid
          return;
        }
      } else if (!window.cid) {
        return;
      }
      if (document.getElementById('bilibiliDanmaku')) {   //节点已存在
        clearInterval(code);
        danmakuFunc();
      } else {
        let node = findInsertPos();
        if (node) {
          clearInterval(code);
          node.appendChild(createNode());
          danmakuFunc();
        }
      }
    }, 2196);
  };

  insertNode();
  addEventListener('hashchange', insertNode);
  addEventListener('pushState', insertNode);
  addEventListener('replaceState', insertNode);
})();