I'm developing with express a web page that when the client clicks in "Send E-mail" redirect to google asking for permission to send email through the client email and after the client gave the permission redirect back and send the email.
The code so far:
'use strict';
const express = require('express');
const googleAuth = require('google-auth-library');
const request = require('request');
let router = express.Router();
let app = express();
const SCOPES = [
'https://mail.google.com/'
,'https://www.googleapis.com/auth/gmail.modify'
,'https://www.googleapis.com/auth/gmail.compose'
,'https://www.googleapis.com/auth/gmail.send'
];
const clientSecret = '***********';
const clientId = '**************';
const redirectUrl = 'http://localhost:8080/access-granted';
const auth = new googleAuth();
const oauth2Client = new auth.OAuth2(clientId, clientSecret, redirectUrl);
const authUrl = oauth2Client.generateAuthUrl({
access_type: 'offline',
scope: SCOPES
});
function sendEmail(auth, content, to , from, subject) {
let encodedMail = new Buffer(
`Content-Type: text/plain; charset="UTF-8"\n` +
`MIME-Version: 1.0\n` +
`Content-Transfer-Encoding: 7bit\n` +
`to: ${to}\n` +
`from: ${from}\n` +
`subject: ${subject}\n\n` +
content
)
.toString(`base64`)
.replace(/\+/g, '-')
.replace(/\//g, '_');
request({
method: "POST",
uri: `https://www.googleapis.com/gmail/v1/users/me/messages/send`,
headers: {
"Authorization": `Bearer ${auth}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"raw": encodedMail
})
},
function(err, response, body) {
if(err){
console.log(err); // Failure
} else {
console.log(body); // Success!
}
});
}
app.use('/static', express.static('./www'));
app.use(router)
router.get('/access-granted', (req, res) => {
sendEmail(req.query.code, 'teste email', 'teste@gmail.com', 'teste@gmail.com', 'teste');
res.sendfile('/www/html/index.html', {root: __dirname})
})
router.get('/request-access', (req, res) => {
res.redirect(authUrl);
});
router.get('/', (req, res) => {
res.sendFile('/www/html/index.html', { root: __dirname });
});
const port = process.env.PORT || 8080;
app.listen(port, () => {
console.log(`Server running at http://localhost:${port}`);
});
module.exports = app;
Every time I try to send a simple E-mail I receive the error 401: Invalid Credentials. But I'm passing in Authorization the client code auth that google sends just gave me...
The recommended way to use google APIs is to use Google API nodejs client which also provides Google OAuth flow. You can then use google.gmail('v1').users.messages.send to send the email :
const gmail = google.gmail('v1');
gmail.users.messages.send({
auth: oauth2Client,
userId: 'me',
resource: {
raw: encodedMail
}
}, function(err, req) {
if (err) {
console.log(err);
} else {
console.log(req);
}
});
auth is OAuth2, the OAuth object that can be populated with your token. You can get the token in the express session :
var oauth2Client = getOAuthClient();
oauth2Client.setCredentials(req.session["tokens"]);
which you've already stored in your OAuth callback endpoint :
var oauth2Client = getOAuthClient();
var session = req.session;
var code = req.query.code;
oauth2Client.getToken(code, function(err, tokens) {
// Now tokens contains an access_token and an optional refresh_token. Save them.
if (!err) {
oauth2Client.setCredentials(tokens);
session["tokens"] = tokens;
res.send(`<html><body><h1>Login successfull</h1><a href=/send-mail>send mail</a></body></html>`);
} else {
res.send(`<html><body><h1>Login failed</h1></body></html>`);
}
});
Here is a complete example inspired from this google API oauth for node.js example :
'use strict';
const express = require('express');
const google = require('googleapis');
const request = require('request');
const OAuth2 = google.auth.OAuth2;
const session = require('express-session');
const http = require('http');
let app = express();
app.use(session({
secret: 'some-secret',
resave: true,
saveUninitialized: true
}));
const gmail = google.gmail('v1');
const SCOPES = [
'https://mail.google.com/',
'https://www.googleapis.com/auth/gmail.modify',
'https://www.googleapis.com/auth/gmail.compose',
'https://www.googleapis.com/auth/gmail.send'
];
const clientSecret = 'CLIENT_SECRET';
const clientId = 'CLIENT_ID';
const redirectUrl = 'http://localhost:8080/access-granted';
const mailContent = "test";
const mailFrom = "someemail@gmail.com";
const mailTo = "someemail@gmail.com";
const mailSubject = "subject";
function getOAuthClient() {
return new OAuth2(clientId, clientSecret, redirectUrl);
}
function getAuthUrl() {
let oauth2Client = getOAuthClient();
let url = oauth2Client.generateAuthUrl({
access_type: 'offline',
scope: SCOPES,
//use this below to force approval (will generate refresh_token)
//approval_prompt : 'force'
});
return url;
}
function sendEmail(auth, content, to, from, subject, cb) {
let encodedMail = new Buffer(
`Content-Type: text/plain; charset="UTF-8"\n` +
`MIME-Version: 1.0\n` +
`Content-Transfer-Encoding: 7bit\n` +
`to: ${to}\n` +
`from: ${from}\n` +
`subject: ${subject}\n\n` +
content
)
.toString(`base64`)
.replace(/\+/g, '-')
.replace(/\//g, '_');
gmail.users.messages.send({
auth: auth,
userId: 'me',
resource: {
raw: encodedMail
}
}, cb);
}
app.use('/send-mail', (req, res) => {
let oauth2Client = getOAuthClient();
oauth2Client.setCredentials(req.session["tokens"]);
sendEmail(oauth2Client, mailContent, mailTo, mailFrom, mailSubject, function(err, response) {
if (err) {
console.log(err);
res.send(`<html><body><h1>Error</h1><a href=/send-mail>send mail</a></body></html>`);
} else {
res.send(`<html><body><h1>Send mail successfull</h1><a href=/send-mail>send mail</a></body></html>`);
}
});
});
app.use('/access-granted', (req, res) => {
let oauth2Client = getOAuthClient();
let session = req.session;
let code = req.query.code;
oauth2Client.getToken(code, function(err, tokens) {
// Now tokens contains an access_token and an optional refresh_token. Save them.
if (!err) {
oauth2Client.setCredentials(tokens);
session["tokens"] = tokens;
res.send(`<html><body><h1>Login successfull</h1><a href=/send-mail>send mail</a></body></html>`);
} else {
res.send(`<html><body><h1>Login failed</h1></body></html>`);
}
});
})
app.use('/', (req, res) => {
let url = getAuthUrl();
res.send(`<html><body><h1>Authentication using google oAuth</h1><a href=${url}>Login</a></body></html>`)
});
let port = process.env.PORT || 8080;
let server = http.createServer(app);
server.listen(port);
server.on('listening', function() {
console.log(`listening to ${port}`);
});