Google Drive API - How to Extract the Results of drive.file.list?

Question

I'm trying to build a search tool for a client. I am working with the google drive API in order to extract a list of different files and their metadata from a specified account, then add those files to a seperate local database that I can then search through. When I console.log(fileArray) within this code, I get the result that I want, the problem is that I can't get it to leave the function's logic. The goal is to take var fileArray, and have that array be what gets mapped out in the database. I can't seem to extract or export it from the function listFiles though. Any ideas? I just want to be able to move the variable after it's been populated by the google drive data to another file.

Thank you!

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, (err, 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, (err, 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)',
  }, (err, 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.');
    }
  });
}

Answer 1

In googleapis for Node.js, drive.files.list returns Promise. So using this, how about this modification?

Modified script:

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);
}

Or also, you can use the following script for 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);
    });
}

Reference:

• googleapis for Node.js