nodejs - connect with gmail-api - node.js

Question

I want to let users to connect to my node.js server with their gmail. I have created a project in the Google Developers Console. Then use the following code:
const express = require('express');
const google = require('googleapis');
const googleAuth = require('google-auth-library');
const credentials = require('../link/of/some/file.json'); // google credential
let clientSecret = credentials.web.client_secret;
let clientId = credentials.web.client_id;
let redirectUrl = credentials.web.redirect_uris[0];
const SCOPES = [
'https://mail.google.com/',
'https://www.googleapis.com/auth/gmail.modify',
'https://www.googleapis.com/auth/gmail.readonly'
];
let auth = new googleAuth();
let oauth2Client = new auth.OAuth2(clientId, clientSecret, redirectUrl);
app.get('/connect', (req, res) => {
let authUrl = oauth2Client.generateAuthUrl({
access_type: 'offline',
scope: SCOPES
});
res.redirect(authUrl);
});
when /connect is called, it will redirect to google page to verify user. After user give access of his/her account, google will automatically call the following api with a code query parameter:
app.get('/auth/callback', (req, res) => {
// 'req.query.code' is provided by google
return oauth2Client.getToken(req.query.code, (err, token) => {
// token value:
/*
{
access_token: 'ya29.Gls2Ba_rXEA5EoBaFH5bPdDDzgaSWOtb0GSJcnaTP47Jh7HwHdF2ZJZOlQaCJBC5wjpq-sOLBVlIM9L8BMslVyHw22nveU0MwQ4iJPTq5vkjXDeitqtoYH8JO83w',
refresh_token: '1/S0C3w-8vnqcrGE4Z2mSW9ctYkaitVuZquBSJ0WJJHUs',
token_type: 'Bearer',
expiry_date: 1514897380473
}
*/
});
});
Now, My problem is, in the above token value, I cannot understand how can I get gmail address from that token. What am I missing???
Any Suggestion? Thanks in advance.

Answer 1

the first steps I would suggest is to store your token somewhere so you don't request it all the time.
Then when you recieve the token you put it in oauth2Client.credentials
oauth2Client.getToken(req.query.code, (err, token) => {
if (err) {
console.log(err);
return;
}
//TODO: Save token somewhere
oauth2Client.credentials = token;
});
Then you use the oauth2Client to do API calls
var gmail = google.gmail('v1');
gmail.users.labels.list({
auth: oauth2Client,
userId: 'me',
}, function(err, response) {
if (err) {
console.log('The API returned an error: ' + err);
return;
}
var labels = response.labels;
if (labels.length == 0) {
console.log('No labels found.');
} else {
console.log('Labels:');
for (var i = 0; i < labels.length; i++) {
var label = labels[i];
console.log('- %s', label.name);
}
}
});

Answer 2

Solved:
I have solve this problem, just calling getProfile, where userId is me. My code is given below:
const SCOPES = [
'https://mail.google.com/',
'https://www.googleapis.com/auth/gmail.modify',
'https://www.googleapis.com/auth/gmail.readonly',
'https://www.googleapis.com/auth/gmail.compose'
];
app.get('/auth/callback', (req, res) => {
return oauth2Client.getToken(req.query.code, (err, token) => {
oauth2Client.credentials = token;
var gmail = google.gmail('v1');
gmail.users.getProfile({
auth: oauth2Client,
userId: "me",
}, function(error, response) {
console.log("getProfile : ", {error, response});
/*
output:
{
emailAddress: 'some.address#gmail.com',
messagesTotal: xxx,
threadsTotal: xxx,
historyId: 'xxxxx'
}
*/
});
});
});
Thanks to all of you.