ニコタグからタグの履歴情報を取得する。

data_format.txt

Data = {
  count: Integer, // タグの個数
  first: Date,    // タグ情報を最初に取得した日時
  last:  Date,    // タグ情報を最後に取得した日時
  tags: [Tag]     // タグ情報の配列
};

Tag = {
  id:    Integer, // タグのID
  name:  String,  // タグ名
  first: Date,    // タグが最初に取得された日時
  last:  Date,    // タグが最後に取得された日時
  good:  Integer, // タグのGood評価
  bad:   Integer, // タグのBad評価
  rank:  Integer  // タグのランク (good - bad)
};

nicotag_gettagsinfo.js

(function() {
  if ('nicotag_getTagsInfo' in window)
    return;

  const parseISO8601 = (function() {
    const regexp = new RegExp(
      "^([0-9]{4})(?:-([0-9]{2})(?:-([0-9]{2})" +
        "(?:T([0-9]{2}):([0-9]{2})(?::([0-9]{2})(?:\.([0-9]+))?)?" +
        "(?:Z|(?:([-+])([0-9]{2}):([0-9]{2})))?)?)?)?$");
    return function (string) {
      var d = string.match(regexp);
      if(d == null) return null;
      var offset = 0;
      var date = new Date(d[1], 0, 1);

      if (d[2]) { date.setMonth(d[2] - 1); }
      if (d[3]) { date.setDate(d[3]); }
      if (d[4]) { date.setHours(d[4]); }
      if (d[5]) { date.setMinutes(d[5]); }
      if (d[6]) { date.setSeconds(d[6]); }
      if (d[7]) { date.setMilliseconds(Number("0." + d[7]) * 1000); }
      if (d[8]) {
        offset = (Number(d[9]) * 60) + Number(d[10]);
        offset *= ((d[8] == '-') ? 1 : -1);
      }

      offset -= date.getTimezoneOffset();
      var time = (Number(date) + (offset * 60 * 1000));
      date.setTime(Number(time));
      return date;
    };
  })();

  const Getter = function(videoID) {
    this._videoID = videoID;
    this._callbacks = [];
  };

  Getter.prototype = {
    _callbacks: null, _lock: false,
    _cache: null,
    get: function(callback, forceUpdate) {
      if (this._cache !== null && !forceUpdate) {
        if (typeof callback === 'function')
          callback(true, this._cache);
        return;
      }

      if (typeof callback === 'function')
        this._callbacks.push(callback);

      if (this._lock) return;
      this._lock = true;

      let self = this;
      function finish(isSuccess, data) {
        if (isSuccess)
          self._cache = data;
        self._callbacks.forEach(function(f) f(isSuccess, data));
        self._callbacks.length = 0;
        self._lock = false;
      }

      let url = 'http://www.nicotag.jp/api/'
        + (forceUpdate ? 'updtagsinfo' : 'gettagsinfo') + '/' + this._videoID;
      GM_xmlhttpRequest({
        method: 'GET',
        url: url,
        headers: { 'User-Agent': 'Mozilla/5.0 Greasemonkey; NicoTag Tab' },
        onload: function(response) {
          if (response.status === 200)
            finish(true, self._parse(response.responseText));
          else
            finish(false, response);
        },
        onerror: function(response) finish(false, response)
      });
    },
    _parse: function(text) {
      let parser = new DOMParser();
      let xml = parser.parseFromString(text, 'application/xml');

      function get(elem, attr) elem.getElementsByTagName(attr)[0].textContent;
      let tags = this._parseTags(xml, get);

      return {
        count: get(xml, 'keep_count'),
        first: parseISO8601(get(xml, 'first_keep')),
        last: parseISO8601(get(xml, 'last_keep')),
        tags: tags
      };
    },
    _parseTags: function(xml, get) {
      let tags = Array.map(
        xml.getElementsByTagName('tag'),
        function(tag) {
          let obj = {
            id: tag.getAttribute('id'),
            name: get(tag, 'name'),
            first: parseISO8601(get(tag, 'first_added')),
            last: parseISO8601(get(tag, 'last_added')),
            good: parseInt(get(tag, 'good'), 10),
            bad:  parseInt(get(tag, 'bad'), 10),
            rank: parseInt(get(tag, 'rank'), 10)
          };
          return obj;
        });

      return tags;
    }
  };

  let getters = {};
  getters.__proto__ = null;
  window.nicotag_getTagsInfo = function(videoID, callback, forceUpdate) {
    let getter = null;
    if (videoID in getters) {
      getter = getters[videoID];
    } else {
      getter = new Getter(videoID);
      getters[videoID] = getter;
    }
    getter.get(callback, forceUpdate);
  };
})();

sample.js

nicotag_getTagsInfo('sm9', function(isSuccess, data) {
  alert(isSuccess);
  alert(uneval(data));
}, true);