Google云端硬盘API-如何提取drive.file.list的结果？ 修改后的脚本：参考：

问题描述

我正在尝试为客户构建搜索工具。我正在使用Google Drive API，以便从指定的帐户中提取不同文件及其元数据的列表，然后将这些文件添加到一个单独的本地数据库中，然后我就可以对其进行搜索。 当我在这段代码中console.log（fileArray）时，我得到了想要的结果，问题是我无法离开函数的逻辑。目标是采用var fileArray，并使该数组成为在数据库中映射的对象。我似乎无法从函数listFiles中提取或导出它。有任何想法吗？我只希望能够在将变量由Google驱动器数据填充到另一个文件后进行移动。

谢谢！

const fs = require('fs');
const readline = require('readline');
const {google} = require('googleapis');
const { file } = require('googleapis/build/src/apis/file');

// If modifying these scopes,delete token.json.
const ScopES = ['https://www.googleapis.com/auth/drive'];
// The file token.json stores the user's access and refresh tokens,and is
// created automatically when the authorization flow completes for the first
// time.
const TOKEN_PATH = 'token.json';

// Load client secrets from a local file.
const authenticate = fs.readFile('credentials.json',(err,content) => {
  if (err) return console.log('Error loading client secret file:',err);
  // Authorize a client with credentials,then call the Google Drive API.
  authorize(JSON.parse(content),listFiles);
});

/**
 * Create an OAuth2 client with the given credentials,and then execute the
 * given callback function.
 * @param {Object} credentials The authorization client credentials.
 * @param {function} callback The callback to call with the authorized client.
 */
function authorize(credentials,callback) {
  const {client_secret,client_id,redirect_uris} = credentials.installed;
  const oauth2client = new google.auth.OAuth2(
      client_id,client_secret,redirect_uris[0]);

  // Check if we have prevIoUsly stored a token.
  fs.readFile(TOKEN_PATH,token) => {
    if (err) return getAccesstoken(oauth2client,callback);
    oauth2client.setCredentials(JSON.parse(token));
    callback(oauth2client);
  });
}

/**
 * Get and store new token after prompting for user authorization,and then
 * execute the given callback with the authorized OAuth2 client.
 * @param {google.auth.OAuth2} oauth2client The OAuth2 client to get token for.
 * @param {getEventsCallback} callback The callback for the authorized client.
 */
function getAccesstoken(oauth2client,callback) {
  const authUrl = oauth2client.generateAuthUrl({
    access_type: 'offline',scope: ScopES,});
  console.log('Authorize this app by visiting this url:',authUrl);
  const rl = readline.createInterface({
    input: process.stdin,output: process.stdout,});
  rl.question('Enter the code from that page here: ',(code) => {
    rl.close();
    oauth2client.getToken(code,token) => {
      if (err) return console.error('Error retrieving access token',err);
      oauth2client.setCredentials(token);
      // Store the token to disk for later program executions
      fs.writeFile(TOKEN_PATH,JSON.stringify(token),(err) => {
        if (err) return console.error(err);
        console.log('Token stored to',TOKEN_PATH);
      });
      callback(oauth2client);
    });
  });
}

/**
 * Lists the names and IDs of up to 10 files.
 * @param {google.auth.OAuth2} auth An authorized OAuth2 client.
 */
function listFiles(auth) {
  const drive = google.drive({version: 'v3',auth});
  const fileArray = [];
   drive.files.list({
    pageSize: 100,fields: 'nextPagetoken,files(id,name,mimeType,createdTime,parents,properties)',},res) => {
    if (err) return console.log('The API returned an error: ' + err);
    const files = res.data.files;
    if (files.length) {
      const filedisplay = []; 
      const fileId = [];
      const mimeType = []; 
      const parents = [];
      const properties = [];
      console.log('Files:');
      for (var i = 0; i < files.length; i++) {
        filedisplay.push(files[i].name);
        fileId.push(files[i].id);
        mimeType.push(files[i].mimeType);
        properties.push(files[i].properties);
        parents.push(files[i].parents);
      }
      for(var y = 0; y < filedisplay.length; y++) {
        fileArray.push({file: filedisplay[y],id: fileId[y],type: mimeType[y],parents: parents[y],properties: properties[y]});
      }
    } else {
      console.log('No files found.');
    }
  });
}

解决方法

在适用于Node.js的googleapis中，drive.files.list返回Promise。那么使用这个修改怎么样？

修改后的脚本：

async function getFileList(drive) {
  const res = await drive.files.list({
    pageSize: 10,fields: "nextPageToken,files(id,name,mimeType,createdTime,parents,properties)",});
  const files = res.data.files;
  const fileArray = [];
  if (files.length) {
    const fileDisplay = [];
    const fileId = [];
    const mimeType = [];
    const parents = [];
    const properties = [];
    console.log("Files:");
    for (var i = 0; i < files.length; i++) {
      fileDisplay.push(files[i].name);
      fileId.push(files[i].id);
      mimeType.push(files[i].mimeType);
      properties.push(files[i].properties);
      parents.push(files[i].parents);
    }
    for (var y = 0; y < fileDisplay.length; y++) {
      fileArray.push({
        file: fileDisplay[y],id: fileId[y],type: mimeType[y],parents: parents[y],properties: properties[y],});
    }
  }
  return fileArray;
}

async function listFiles(auth) {
  const drive = google.drive({ version: "v3",auth });
  const fileArray = await getFileList(drive).catch((err) => {
    if (err) console.log(err);
  });
  console.log(fileArray);
}

或者，您也可以将以下脚本用于listFiles。

function listFiles(auth) {
  const drive = google.drive({ version: "v3",auth });
  getFileList(drive)
    .then((fileArray) => console.log(fileArray))
    .catch((err) => {
      if (err) console.log(err);
    });
}

参考：

• googleapis for Node.js