index.js

const authConfig = {
  "siteName": "GoIndex", // Website name
  "version": "_4.28", // Program Version. Users do not modify manually
  /*"client_id": "202264815644.apps.googleusercontent.com",
  "client_secret": "X4Z3ca8xfWDb1Voo-F9a7ZxJ",*/
  // [Note] It is strongly recommended to use your own client_id and client_secret
  "client_id": "",
  "client_secret": "",
  "refresh_token": "", // Authorize token
  /**
   * Set up multiple Drives to display; add multiples by format
   * [id]: It can be the team disk id, subfolder id, or "root" (representing the root directory of personal disk);
   * [name]: Display name
   * [user]: Basic Auth's username
   * [pass]: Basic Auth Password
   * [protect_file_link]: Basic Auth Whether it is used to protect the file link, the default value (when not set) is false, that is, the file link is not protected (convenient for straight-chain download / external playback, etc.)
   * Basic Auth for each disk can be set individually. Basic Auth protects all folders / subfolders in the disk by default
   * [Note] The file link is not protected by default, which can facilitate straight-chain download / external playback;
   * If you want to protect the file link, you need to set protect_file_link to true. At this time, if you want to perform external playback and other operations, you need to replace host with user: pass @ host
   * No Basic Auth disk is required, just keep user and pass empty at the same time. (No need to set it directly)
   * [Note] For the disk whose id is set to the subfolder id, the search function will not be supported (it does not affect other disks).
   */
  "roots": [
    {
      id: "root",
      name: "Personal disk"
    },
    {
      id: "drive_id",
      name: "Team plate 1",
      user: 'user1',
      pass: "111",
      protect_file_link: true
    },
    {
      id: "folder_id",
      name: "folder",
      // It is possible to set only the password, only the user name, and the user name and password at the same time
      user: '',
      pass: "222",
      protect_file_link: false
    }
  ],
  /**
   * The number displayed on each page of the file list page. [Recommended setting value is between 100 and 1000];
   * If the setting is greater than 1000, it will cause an error when requesting drive api;
   * If the set value is too small, it will cause the incremental loading (page loading) of the scroll bar of the file list page to fail;
   * Another effect of this value is that if the number of files in the directory is greater than this setting value (that is, multiple pages need to be displayed), the results of the first listing directory will be cached.
   */
  "files_list_page_size": 500,
  /**
   * The number displayed on each page of the search results page. [Recommended setting value is between 50 and 1000];
   * If the setting is greater than 1000, it will cause an error when requesting drive api;
   * If the set value is too small, it will cause the incremental loading (page loading) of the scroll bar of the search results page to fail;
   * The size of this value affects the response speed of the search operation.
   */
  "search_result_list_page_size": 50,
  // Confirm that cors can be opened
  "enable_cors_file_down": false,
  /**
   * The basic auth above already contains the function of global protection in the disk. So by default, the password in the .password file is no longer authenticated;
   * If you still need to verify the password in the .password file for certain directories based on global authentication, set this option to true;
   * [Note] If the password verification of the .password file is turned on, each time the directory is listed, the overhead of querying the directory for the existence of the .password file is additionally added.
   */
  "enable_password_file_verify": false
};

/**
 * web ui 设置
 */
const uiConfig = {
  // This version only supports material
  "theme": "material-new", // DO NOT set it to classic
  "dark_mode": true,
  "main_color": "blue-grey",
  "accent_color": "blue",
  /*"main_color": "light-green",
  "accent_color": "green",*/
  "fluid_navigation_bar": true,
};

/**
 * global functions
 */
const FUNCS = {
  /**
   * Transform into relatively safe search keywords for Google search morphology
   */
  formatSearchKeyword: function (keyword) {
    let nothing = "";
    let space = " ";
    if (!keyword) return nothing;
    return keyword.replace(/(!=)|['"=<>/\\:]/g, nothing)
      .replace(/[,，|(){}]/g, space)
      .trim()
  }

};

/**
 * global consts
 * @type {{folder_mime_type: string, default_file_fields: string, gd_root_type: {share_drive: number, user_drive: number, sub_folder: number}}}
 */
const CONSTS = new (class {
  default_file_fields = 'parents,id,name,mimeType,modifiedTime,createdTime,fileExtension,size';
  gd_root_type = {
    user_drive: 0,
    share_drive: 1,
    sub_folder: 2
  };
  folder_mime_type = 'application/vnd.google-apps.folder';
})();


// gd instances
var gds = [];

function html(current_drive_order = 0, model = {}) {
  return `
<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0,maximum-scale=1.0, user-scalable=no"/>
  <title>${authConfig.siteName}</title>
  <script>
    window.drive_names = JSON.parse('${JSON.stringify(authConfig.roots.map(it => it.name))}');
    window.MODEL = JSON.parse('${JSON.stringify(model)}');
    window.current_drive_order = ${current_drive_order};
    window.UI = JSON.parse('${JSON.stringify(uiConfig)}');
  </script>
<script src="//cdn.jsdelivr.net/gh/jquery/jquery@3.2/dist/jquery.min.js"></script>
  <script src="//cdn.jsdelivr.net/gh/Sparoney/goindex/themes/${authConfig.theme}/app.js"></script>
</head>
<body>
</body>
</html>
`;
};

addEventListener('fetch', event => {
  event.respondWith(handleRequest(event.request));
});

/**
 * Fetch and log a request
 * @param {Request} request
 */
async function handleRequest(request) {
  if (gds.length === 0) {
    for (let i = 0; i < authConfig.roots.length; i++) {
      const gd = new googleDrive(authConfig, i);
      await gd.init();
      gds.push(gd)
    }
    // This operation is parallel and improves efficiency
    let tasks = [];
    gds.forEach(gd => {
      tasks.push(gd.initRootType());
    });
    for (let task of tasks) {
      await task;
    }
  }

  // From path extract from drive order
  // 并根据 drive order 获取对应的 gd instance
  let gd;
  let url = new URL(request.url);
  let path = url.pathname;

  /**
   * Redirect to start page
   * @returns {Response}
   */
  function redirectToIndexPage() {
    return new Response('', {status: 301, headers: {'Location': `${url.origin}/0:/`}});
  }

  if (path == '/') return redirectToIndexPage();
  if (path.toLowerCase() == '/favicon.ico') {
    // You can find a favicon later
    return new Response('', {status: 404})
  }

  // Special command format
  const command_reg = /^\/(?<num>\d+):(?<command>[a-zA-Z0-9]+)$/g;
  const match = command_reg.exec(path);
  if (match) {
    const num = match.groups.num;
    const order = Number(num);
    if (order >= 0 && order < gds.length) {
      gd = gds[order];
    } else {
      return redirectToIndexPage()
    }
    // basic auth
    for (const r = gd.basicAuthResponse(request); r;) return r;
    const command = match.groups.command;
    // search for
    if (command === 'search') {
      if (request.method === 'POST') {
        // search results
        return handleSearch(request, gd);
      } else {
        const params = url.searchParams;
        // Search page
        return new Response(html(gd.order, {
            q: params.get("q") || '',
            is_search_page: true,
            root_type: gd.root_type
          }),
          {
            status: 200,
            headers: {'Content-Type': 'text/html; charset=utf-8'}
          });
      }
    } else if (command === 'id2path' && request.method === 'POST') {
      return handleId2Path(request, gd)
    }
  }

  // Desired path format
  const common_reg = /^\/\d+:\/.*$/g;
  try {
    if (!path.match(common_reg)) {
      return redirectToIndexPage();
    }
    let split = path.split("/");
    let order = Number(split[1].slice(0, -1));
    if (order >= 0 && order < gds.length) {
      gd = gds[order];
    } else {
      return redirectToIndexPage()
    }
  } catch (e) {
    return redirectToIndexPage()
  }

  // basic auth
  // for (const r = gd.basicAuthResponse(request); r;) return r;
  const basic_auth_res = gd.basicAuthResponse(request);

  path = path.replace(gd.url_path_prefix, '') || '/';
  if (request.method == 'POST') {
    return basic_auth_res || apiRequest(request, gd);
  }

  let action = url.searchParams.get('a');

  if (path.substr(-1) == '/' || action != null) {
    return basic_auth_res || new Response(html(gd.order, {root_type: gd.root_type}), {
      status: 200,
      headers: {'Content-Type': 'text/html; charset=utf-8'}
    });
  } else {
    if (path.split('/').pop().toLowerCase() == ".password") {
      return basic_auth_res || new Response("", {status: 404});
    }
    let file = await gd.file(path);
    let range = request.headers.get('Range');
    const inline_down = 'true' === url.searchParams.get('inline');
    if (gd.root.protect_file_link && basic_auth_res) return basic_auth_res;
    return gd.down(file.id, range, inline_down);
  }
}


async function apiRequest(request, gd) {
  let url = new URL(request.url);
  let path = url.pathname;
  path = path.replace(gd.url_path_prefix, '') || '/';

  let option = {status: 200, headers: {'Access-Control-Allow-Origin': '*'}}

  if (path.substr(-1) == '/') {
    let form = await request.formData();
    // This can increase the speed when listing directories for the first time. The disadvantage is that if the password verification fails, the overhead of listing directories will still be incurred
    let deferred_list_result = gd.list(path, form.get('page_token'), Number(form.get('page_index')));

    // check .password file, if `enable_password_file_verify` is true
    if (authConfig['enable_password_file_verify']) {
      let password = await gd.password(path);
      // console.log("dir password", password);
      if (password && password.replace("\n", "") !== form.get('password')) {
        let html = `{"error": {"code": 401,"message": "password error."}}`;
        return new Response(html, option);
      }
    }

    let list_result = await deferred_list_result;
    return new Response(JSON.stringify(list_result), option);
  } else {
    let file = await gd.file(path);
    let range = request.headers.get('Range');
    return new Response(JSON.stringify(file));
  }
}

// deal with search
async function handleSearch(request, gd) {
  const option = {status: 200, headers: {'Access-Control-Allow-Origin': '*'}};
  let form = await request.formData();
  let search_result = await
    gd.search(form.get('q') || '', form.get('page_token'), Number(form.get('page_index')));
  return new Response(JSON.stringify(search_result), option);
}

/**
 * deal with id2path
 * @param request Id parameter required
 * @param gd
 * @returns {Promise<Response>} [Note] If the item represented by the id received from the front desk is not under the target gd disk, then the response will be returned to the front desk with an empty string ""
 */
async function handleId2Path(request, gd) {
  const option = {status: 200, headers: {'Access-Control-Allow-Origin': '*'}};
  let form = await request.formData();
  let path = await gd.findPathById(form.get('id'));
  return new Response(path || '', option);
}

class googleDrive {
  constructor(authConfig, order) {
    // Each disk corresponds to an order, corresponding to a gd instance
    this.order = order;
    this.root = authConfig.roots[order];
    this.root.protect_file_link = this.root.protect_file_link || false;
    this.url_path_prefix = `/${order}:`;
    this.authConfig = authConfig;
    // TODO: The invalid refresh strategy of these caches can be formulated later
    // path id
    this.paths = [];
    // path file
    this.files = [];
    // path pass
    this.passwords = [];
    // id <-> path
    this.id_path_cache = {};
    this.id_path_cache[this.root['id']] = '/';
    this.paths["/"] = this.root['id'];
    /*if (this.root['pass'] != "") {
      this.passwords['/'] = this.root['pass'];
    }*/
    // this.init();
  }

  /**
   * Initial authorization; then obtain user_drive_real_root_id
   * @returns {Promise<void>}
   */
  async init() {
    await this.accessToken();
    /*await (async () => {
        // Get only 1 time
        if (authConfig.user_drive_real_root_id) return;
        const root_obj = await (gds[0] || this).findItemById('root');
        if (root_obj && root_obj.id) {
            authConfig.user_drive_real_root_id = root_obj.id
        }
    })();*/
    // Wait for user_drive_real_root_id , and only get it once
    if (authConfig.user_drive_real_root_id) return;
    const root_obj = await (gds[0] || this).findItemById('root');
    if (root_obj && root_obj.id) {
      authConfig.user_drive_real_root_id = root_obj.id
    }
  }

  /**
   * Get the root directory type, set to root_type
   * @returns {Promise<void>}
   */
  async initRootType() {
    const root_id = this.root['id'];
    const types = CONSTS.gd_root_type;
    if (root_id === 'root' || root_id === authConfig.user_drive_real_root_id) {
      this.root_type = types.user_drive;
    } else {
      const obj = await this.getShareDriveObjById(root_id);
      this.root_type = obj ? types.share_drive : types.sub_folder;
    }
  }

  /**
   * Returns a response that requires authorization, or null
   * @param request
   * @returns {Response|null}
   */
  basicAuthResponse(request) {
    const user = this.root.user || '',
      pass = this.root.pass || '',
      _401 = new Response('Unauthorized', {
        headers: {'WWW-Authenticate': `Basic realm="goindex:drive:${this.order}"`},
        status: 401
      });
    if (user || pass) {
      const auth = request.headers.get('Authorization')
      if (auth) {
        try {
          const [received_user, received_pass] = atob(auth.split(' ').pop()).split(':');
          return (received_user === user && received_pass === pass) ? null : _401;
        } catch (e) {
        }
      }
    } else return null;
    return _401;
  }

  async down(id, range = '', inline = false) {
    let url = `https://www.googleapis.com/drive/v3/files/${id}?alt=media`;
    let requestOption = await this.requestOption();
    requestOption.headers['Range'] = range;
    let res = await fetch(url, requestOption);
    const {headers} = res = new Response(res.body, res)
    this.authConfig.enable_cors_file_down && headers.append('Access-Control-Allow-Origin', '*');
    inline === true && headers.set('Content-Disposition', 'inline');
    return res;
  }

  async file(path) {
    if (typeof this.files[path] == 'undefined') {
      this.files[path] = await this._file(path);
    }
    return this.files[path];
  }

  async _file(path) {
    let arr = path.split('/');
    let name = arr.pop();
    name = decodeURIComponent(name).replace(/\'/g, "\\'");
    let dir = arr.join('/') + '/';
    // console.log(name, dir);
    let parent = await this.findPathId(dir);
    // console.log(parent);
    let url = 'https://www.googleapis.com/drive/v3/files';
    let params = {'includeItemsFromAllDrives': true, 'supportsAllDrives': true};
    params.q = `'${parent}' in parents and name = '${name}' and trashed = false`;
    params.fields = "files(id, name, mimeType, size ,createdTime, modifiedTime, iconLink, thumbnailLink)";
    url += '?' + this.enQuery(params);
    let requestOption = await this.requestOption();
    let response = await fetch(url, requestOption);
    let obj = await response.json();
    // console.log(obj);
    return obj.files[0];
  }

  // Cache through reqeust cache
  async list(path, page_token = null, page_index = 0) {
    if (this.path_children_cache == undefined) {
      // { <path> :[ {nextPageToken:'',data:{}}, {nextPageToken:'',data:{}} ...], ...}
      this.path_children_cache = {};
    }

    if (this.path_children_cache[path]
      && this.path_children_cache[path][page_index]
      && this.path_children_cache[path][page_index].data
    ) {
      let child_obj = this.path_children_cache[path][page_index];
      return {
        nextPageToken: child_obj.nextPageToken || null,
        curPageIndex: page_index,
        data: child_obj.data
      };
    }

    let id = await this.findPathId(path);
    let result = await this._ls(id, page_token, page_index);
    let data = result.data;
    // Cache multiple pages
    if (result.nextPageToken && data.files) {
      if (!Array.isArray(this.path_children_cache[path])) {
        this.path_children_cache[path] = []
      }
      this.path_children_cache[path][Number(result.curPageIndex)] = {
        nextPageToken: result.nextPageToken,
        data: data
      };
    }

    return result
  }


  async _ls(parent, page_token = null, page_index = 0) {
    // console.log("_ls", parent);

    if (parent == undefined) {
      return null;
    }
    let obj;
    let params = {'includeItemsFromAllDrives': true, 'supportsAllDrives': true};
    params.q = `'${parent}' in parents and trashed = false AND name !='.password'`;
    params.orderBy = 'folder,name,modifiedTime desc';
    params.fields = "nextPageToken, files(id, name, mimeType, size , modifiedTime)";
    params.pageSize = this.authConfig.files_list_page_size;

    if (page_token) {
      params.pageToken = page_token;
    }
    let url = 'https://www.googleapis.com/drive/v3/files';
    url += '?' + this.enQuery(params);
    let requestOption = await this.requestOption();
    let response = await fetch(url, requestOption);
    obj = await response.json();

    return {
      nextPageToken: obj.nextPageToken || null,
      curPageIndex: page_index,
      data: obj
    };

    /*do {
        if (pageToken) {
            params.pageToken = pageToken;
        }
        let url = 'https://www.googleapis.com/drive/v3/files';
        url += '?' + this.enQuery(params);
        let requestOption = await this.requestOption();
        let response = await fetch(url, requestOption);
        obj = await response.json();
        files.push(...obj.files);
        pageToken = obj.nextPageToken;
    } while (pageToken);*/

  }

  async password(path) {
    if (this.passwords[path] !== undefined) {
      return this.passwords[path];
    }

    // console.log("load", path, ".password", this.passwords[path]);

    let file = await this.file(path + '.password');
    if (file == undefined) {
      this.passwords[path] = null;
    } else {
      let url = `https://www.googleapis.com/drive/v3/files/${file.id}?alt=media`;
      let requestOption = await this.requestOption();
      let response = await this.fetch200(url, requestOption);
      this.passwords[path] = await response.text();
    }

    return this.passwords[path];
  }


  /**
   * Get share drive information by id
   * @param any_id
   * @returns {Promise<null|{id}|any>} Any abnormal conditions are returned null
   */
  async getShareDriveObjById(any_id) {
    if (!any_id) return null;
    if ('string' !== typeof any_id) return null;

    let url = `https://www.googleapis.com/drive/v3/drives/${any_id}`;
    let requestOption = await this.requestOption();
    let res = await fetch(url, requestOption);
    let obj = await res.json();
    if (obj && obj.id) return obj;

    return null
  }


  /**
   * search for
   * @returns {Promise<{data: null, nextPageToken: null, curPageIndex: number}>}
   */
  async search(origin_keyword, page_token = null, page_index = 0) {
    const types = CONSTS.gd_root_type;
    const is_user_drive = this.root_type === types.user_drive;
    const is_share_drive = this.root_type === types.share_drive;

    const empty_result = {
      nextPageToken: null,
      curPageIndex: page_index,
      data: null
    };

    if (!is_user_drive && !is_share_drive) {
      return empty_result;
    }
    let keyword = FUNCS.formatSearchKeyword(origin_keyword);
    if (!keyword) {
      // The keyword is empty, return
      return empty_result;
    }
    let words = keyword.split(/\s+/);
    let name_search_str = `name contains '${words.join("' AND name contains '")}'`;

    // corpora is a personal drive for user and a team drive for drive. With driveId
    let params = {};
    if (is_user_drive) {
      params.corpora = 'user'
    }
    if (is_share_drive) {
      params.corpora = 'drive';
      params.driveId = this.root.id;
      // This parameter will only be effective until June 1, 2020. Afterwards shared drive items will be included in the results.
      params.includeItemsFromAllDrives = true;
      params.supportsAllDrives = true;
    }
    if (page_token) {
      params.pageToken = page_token;
    }
    params.q = `trashed = false AND name !='.password' AND (${name_search_str})`;
    params.fields = "nextPageToken, files(id, name, mimeType, size , modifiedTime)";
    params.pageSize = this.authConfig.search_result_list_page_size;
    // params.orderBy = 'folder,name,modifiedTime desc';

    let url = 'https://www.googleapis.com/drive/v3/files';
    url += '?' + this.enQuery(params);
    // console.log(params)
    let requestOption = await this.requestOption();
    let response = await fetch(url, requestOption);
    let res_obj = await response.json();

    return {
      nextPageToken: res_obj.nextPageToken || null,
      curPageIndex: page_index,
      data: res_obj
    };
  }


  /**
* Get the file object of the upper folder of this file or folder layer by layer. Note: It will be very slow! ! !
   * Up to find the root directory (root id) of the current gd object
   * Only consider a single upward chain.
   * [Note] If the item represented by this id is not under the target gd disk, then this function will return null
   *
   * @param child_id
   * @param contain_myself
   * @returns {Promise<[]>}
   */
  async findParentFilesRecursion(child_id, contain_myself = true) {
    const gd = this;
    const gd_root_id = gd.root.id;
    const user_drive_real_root_id = authConfig.user_drive_real_root_id;
    const is_user_drive = gd.root_type === CONSTS.gd_root_type.user_drive;

    // End point query id from bottom to top
    const target_top_id = is_user_drive ? user_drive_real_root_id : gd_root_id;
    const fields = CONSTS.default_file_fields;

    // [{},{},...]
    const parent_files = [];
    let meet_top = false;

    async function addItsFirstParent(file_obj) {
      if (!file_obj) return;
      if (!file_obj.parents) return;
      if (file_obj.parents.length < 1) return;

      // ['','',...]
      let p_ids = file_obj.parents;
      if (p_ids && p_ids.length > 0) {
        // its first parent
        const first_p_id = p_ids[0];
        if (first_p_id === target_top_id) {
          meet_top = true;
          return;
        }
        const p_file_obj = await gd.findItemById(first_p_id);
        if (p_file_obj && p_file_obj.id) {
          parent_files.push(p_file_obj);
          await addItsFirstParent(p_file_obj);
        }
      }
    }

    const child_obj = await gd.findItemById(child_id);
    if (contain_myself) {
      parent_files.push(child_obj);
    }
    await addItsFirstParent(child_obj);

    return meet_top ? parent_files : null
  }

  /**
   * Get the path relative to the root directory of this disk
   * @param child_id
   * @returns {Promise<string>} [Note] If the item represented by this id is not in the target gd disk, then this method will return an empty string ""
   */
  async findPathById(child_id) {
    if (this.id_path_cache[child_id]) {
      return this.id_path_cache[child_id];
    }

    const p_files = await this.findParentFilesRecursion(child_id);
    if (!p_files || p_files.length < 1) return '';

    let cache = [];
    // Cache the path and id of each level found
    p_files.forEach((value, idx) => {
      const is_folder = idx === 0 ? (p_files[idx].mimeType === CONSTS.folder_mime_type) : true;
      let path = '/' + p_files.slice(idx).map(it => it.name).reverse().join('/');
      if (is_folder) path += '/';
      cache.push({id: p_files[idx].id, path: path})
    });

    cache.forEach((obj) => {
      this.id_path_cache[obj.id] = obj.path;
      this.paths[obj.path] = obj.id
    });

    /*const is_folder = p_files[0].mimeType === CONSTS.folder_mime_type;
    let path = '/' + p_files.map(it => it.name).reverse().join('/');
    if (is_folder) path += '/';*/

    return cache[0].path;
  }


  // Get file item based on id
  async findItemById(id) {
    const is_user_drive = this.root_type === CONSTS.gd_root_type.user_drive;
    let url = `https://www.googleapis.com/drive/v3/files/${id}?fields=${CONSTS.default_file_fields}${is_user_drive ? '' : '&supportsAllDrives=true'}`;
    let requestOption = await this.requestOption();
    let res = await fetch(url, requestOption);
    return await res.json()
  }

  async findPathId(path) {
    let c_path = '/';
    let c_id = this.paths[c_path];

    let arr = path.trim('/').split('/');
    for (let name of arr) {
      c_path += name + '/';

      if (typeof this.paths[c_path] == 'undefined') {
        let id = await this._findDirId(c_id, name);
        this.paths[c_path] = id;
      }

      c_id = this.paths[c_path];
      if (c_id == undefined || c_id == null) {
        break;
      }
    }
    // console.log(this.paths);
    return this.paths[path];
  }

  async _findDirId(parent, name) {
    name = decodeURIComponent(name).replace(/\'/g, "\\'");

    // console.log("_findDirId", parent, name);

    if (parent == undefined) {
      return null;
    }

    let url = 'https://www.googleapis.com/drive/v3/files';
    let params = {'includeItemsFromAllDrives': true, 'supportsAllDrives': true};
    params.q = `'${parent}' in parents and mimeType = 'application/vnd.google-apps.folder' and name = '${name}'  and trashed = false`;
    params.fields = "nextPageToken, files(id, name, mimeType)";
    url += '?' + this.enQuery(params);
    let requestOption = await this.requestOption();
    let response = await fetch(url, requestOption);
    let obj = await response.json();
    if (obj.files[0] == undefined) {
      return null;
    }
    return obj.files[0].id;
  }

  async accessToken() {
    console.log("accessToken");
    if (this.authConfig.expires == undefined || this.authConfig.expires < Date.now()) {
      const obj = await this.fetchAccessToken();
      if (obj.access_token != undefined) {
        this.authConfig.accessToken = obj.access_token;
        this.authConfig.expires = Date.now() + 3500 * 1000;
      }
    }
    return this.authConfig.accessToken;
  }

  async fetchAccessToken() {
    console.log("fetchAccessToken");
    const url = "https://www.googleapis.com/oauth2/v4/token";
    const headers = {
      'Content-Type': 'application/x-www-form-urlencoded'
    };
    const post_data = {
      'client_id': this.authConfig.client_id,
      'client_secret': this.authConfig.client_secret,
      'refresh_token': this.authConfig.refresh_token,
      'grant_type': 'refresh_token'
    }

    let requestOption = {
      'method': 'POST',
      'headers': headers,
      'body': this.enQuery(post_data)
    };

    const response = await fetch(url, requestOption);
    return await response.json();
  }

  async fetch200(url, requestOption) {
    let response;
    for (let i = 0; i < 3; i++) {
      response = await fetch(url, requestOption);
      console.log(response.status);
      if (response.status != 403) {
        break;
      }
      await this.sleep(800 * (i + 1));
    }
    return response;
  }

  async requestOption(headers = {}, method = 'GET') {
    const accessToken = await this.accessToken();
    headers['authorization'] = 'Bearer ' + accessToken;
    return {'method': method, 'headers': headers};
  }

  enQuery(data) {
    const ret = [];
    for (let d in data) {
      ret.push(encodeURIComponent(d) + '=' + encodeURIComponent(data[d]));
    }
    return ret.join('&');
  }

  sleep(ms) {
    return new Promise(function (resolve, reject) {
      let i = 0;
      setTimeout(function () {
        console.log('sleep' + ms);
        i++;
        if (i >= 2) reject(new Error('i>=2'));
        else resolve(i);
      }, ms);
    })
  }
}

String.prototype.trim = function (char) {
  if (char) {
    return this.replace(new RegExp('^\\' + char + '+|\\' + char + '+$', 'g'), '');
  }
  return this.replace(/^\s+|\s+$/g, '');
};