Google URL Shortener

app.js

'use strict';

var express = require('express');
var { google } = require('googleapis');

// API keys, Client ID and Client Secret @ https://code.google.com/apis/console
var GAPI = "AIzaSyBheQiEQ_NYpsFugde-jb8hmC7FBAFEVHI";
var CLIENT_ID = "507857393893-tmnp49jq8of3en7m81dqdidedupris8d.apps.googleusercontent.com";
var CLIENT_SECRET = "aLHvXDEV_I_YpAA4Y9tl1tdg";
var REDIRECT_URL = "http://localhost:3000/oauth2callback";

var urlshortener = google.urlshortener('v1');
var OAuth2Client = google.auth.OAuth2;
var oauth2Client = new OAuth2Client(CLIENT_ID, CLIENT_SECRET, REDIRECT_URL);

var app = express();
app.get('/', (req, res) => res.send('Google URL Shortener - API Demo'));

// Get Information About Short URL
app.get('/get', (req, res) => {
  var params = {
    "auth": GAPI,
    "shortUrl": 'https://goo.gl/MTEs4'
  };
  urlshortener.url.get(params, function (err, response) {
    if (err || !response) {
      res.send("Error On Get");
    } else {
      res.json(response.data);
    }
  });
});

// Generate Short URL
app.get('/insert', (req, res) => {
  var params = {
    "auth": GAPI,
    "resource": {
      "longUrl": "http://niralar.com/"
    }
  };
  urlshortener.url.insert(params, function (err, response) {
    if (err || !response) {
      res.send("Error On Insert");
    } else {
      res.json(response.data);
    }
  });
});

// Retrieves a list of URLs shortened by the authenticated user.
app.get('/list', (req, res) => {
  const url = oauth2Client.generateAuthUrl({
    access_type: 'offline', // OAuth2 (Generate AuthUrl)
    scope: 'https://www.googleapis.com/auth/urlshortener'
  });
  res.redirect(url);
});

app.get('/oauth2callback', (req, res) => {
  var code = req.query.code + '#';
  oauth2Client.getToken(code, (err, tokens) => {
    if (err || !tokens) {
      res.send("Error On OAuth");
    } else {
      oauth2Client.setCredentials(tokens);
      urlshortener.url.list({ auth: oauth2Client }, function (err, response) {
        if (err || !response) {
          res.send("Error On Listing");
        } else {
          res.json(response.data);
        }
      });
    }
  });
});

app.listen(3000, () => console.log('Example app listening on port 3000!'));