boilerplate for building a command-line app in nodejs that uses OAuth2 client id to update Google sheets

updateSheets.js

// updateSheets.js
// ------------------------------------------------------------------
//
// created: Tue Jan 14 05:22:42 2020
// last saved: <2020-January-14 06:34:31>

const fs       = require('fs'),
      path     = require('path'),
      util     = require('util'),
      {google} = require('googleapis'),
      readline = require('readline'),
      clipboardy = require('clipboardy'),
      opn      = require('opn');
      
const GOOG_APIS_SCOPES = ['https://www.googleapis.com/auth/spreadsheets'];

// ==================================================================
// The following nonsense is required in order to get
// ctrl-v (paste) events to work in readline on Windows. 
readline.emitKeypressEvents(process.stdin);
const rl = readline.createInterface({
  input: process.stdin,
  output: process.stdout
});

process.stdin.setRawMode(true);
process.stdin.on('keypress', (str, key) => {
  if (key.ctrl && key.name === 'v') {
    rl.write(clipboardy.readSync());
  }
});
// ==================================================================


function sleep (time) {
  return new Promise((resolve) => setTimeout(resolve, time));
}

function getNewGsuiteToken(oAuth2Client, tokenStashPath, projectId, callback) {
  console.log('\nYou must authorize Sheet updater to create a new sheet.\n');
  console.log('This script will now open a browser tab. After granting consent, you will');
  console.log('receive a one-time code. Return here and paste it in, to continue....\n');

  sleep(4200)
    .then(() => {
    const authUrl = oAuth2Client.generateAuthUrl({
            access_type: 'offline',
            scope: GOOG_APIS_SCOPES
          });
    // Authorize this app by visiting the url
    opn(authUrl, {wait: false});
    rl.question('Paste the one-time-code: ', (code) => {
      oAuth2Client.getToken(code, (e, token) => {
        console.log(`Thanks! You have successfully authorized ${projectId} to do its thing.`);
        if (e) {
          console.log('cannot get token?');
          console.log(e);
          return callback(e);
        }
        oAuth2Client.setCredentials(token);
        // Store the token to disk for later program executions
        let dataToStore = JSON.stringify(token, null, 2) + '\n';
        fs.writeFile(tokenStashPath, dataToStore, (e) => {
          if (e) {
            console.error(e); // this is a non-fatal condition
          }
          else {
            console.log('stored token in token stash: ' + tokenStashPath);
          }
          callback(null, oAuth2Client);
        });
      });
    });
  });
}

/**
 * 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 oauth2Authorize(credentials, callback) {
  const {client_secret, client_id, redirect_uris} = credentials;
  const oAuth2Client = new google.auth.OAuth2(client_id, client_secret, redirect_uris[0]);
  const tokenStashPath = path.join('.', ".gsheets_token_stash.json");
  // Check if there is a previously stashed token.
  //console.log('token stash path: ' + tokenStashPath);
  fs.readFile(tokenStashPath, (e, data) => {
    if (e) {
      console.log('cannot read stashed token: ' + e);
      return getNewGsuiteToken(oAuth2Client, tokenStashPath, projectId, callback);
    }
    let stashedToken = JSON.parse(data);
    
    //console.log('read stashed token: ' + util.format(stashedToken));
    //let expiry = new Date(stashedToken.expiry_date);
    //let now = new Date();
    //console.log('expires: ' + expiry.toISOString());
    //console.log('now: ' + now.toISOString());
    
    // expiry and refresh is handled automagically
    oAuth2Client.setCredentials(stashedToken); 
    callback(null, oAuth2Client);
  });
}

// for setup, visit console.cloud.google.com
// IAM
// Create Credentials
// OAuth2 client id
// Other
// (name it)
// Save
// Edit
// Download JSON


// The downloaded credentials file ought to look like this:
// {
//   "installed": {
//     "client_id": "8675309-b9aa47c7aa3ed0bc03ac569c.apps.googleusercontent.com",
//     "project_id": "my-project-name",
//     "auth_uri": "https://accounts.google.com/o/oauth2/auth",
//     "token_uri": "https://www.googleapis.com/oauth2/v3/token",
//     "auth_provider_x509_cert_url": "https://www.googleapis.com/oauth2/v1/certs",
//     "client_secret": "ABCDEFGHIBAADBEEF",
//     "redirect_uris": [
//       "urn:ietf:wg:oauth:2.0:oob",
//       "http://localhost"
//     ]
//   }
// }


const clientCredentialsFile = path.join(".", "gsheets_client_credentials.json");
fs.readFile(clientCredentialsFile, (e, content) => {
  if (e) {
    console.log('Error loading client credentials file:', e);
    return;
  }
  let credentials = JSON.parse(content).installed;
  oauth2Authorize(credentials, doTheThing(credentials.project_id));
});


function doTheThing(projectId) {
  return function(e, oAuth2Client) {
    rl.close();
    if (e) {
      return console.log(e);
    }
    console.log(`${projectId} is authorized to do its thing.`);
  };
}