1import { getAuth, signInWithPopup, GoogleAuthProvider } from "firebase/auth";
2
3const auth = getAuth();
4signInWithPopup(auth, provider)
5  .then((result) => {
6    // This gives you a Google Access Token. You can use it to access the Google API.
7    const credential = GoogleAuthProvider.credentialFromResult(result);
8    const token = credential.accessToken;
9    // The signed-in user info.
10    const user = result.user;
11    // ...
12  }).catch((error) => {
13    // Handle Errors here.
14    const errorCode = error.code;
15    const errorMessage = error.message;
16    // The email of the user's account used.
17    const email = error.customData.email;
18    // The AuthCredential type that was used.
19    const credential = GoogleAuthProvider.credentialFromError(error);
20    // ...
21  });

1https://www.googleapis.com/oauth2/v1/tokeninfo?access_token=accessToken

1{
2 "issued_to": "75010101072-jq0gaom2tpgk01t78ffjisvgsgggggg.apps.googleusercontent.com",
3  "audience": "75069777777-jq0gaom2fsfsrv78ffjisvgshfafess.apps.googleusercontent.com",
4  "user_id": "112901390458597sfstv",
5  "scope": "openid https://www.googleapis.com/auth/userinfo.profile https://www.googleapis.com/auth/userinfo.email https://mail.google.com/",
6  "expires_in": 2244,
7  "email": "email@gmail.com",
8  "verified_email": true,
9  "access_type": "online"
10}

1"access_type": "offline"

1npm install googleapis

1const express = require('express')
2const {google} = require('googleapis');
3const path = require('path');
4const nodemailer = require('nodemailer');
5
6
7const router=express.Router()
8
9//replace below with your creds, also note that i hard coded the  
10//refresh and access token that i got from the response   
11//ideally you'd save it somewhere and load it in as a variable  
12 //and refetch if it's invalid   
13
14const creds={
15  client_email:"email1@gmail.com",
16  client_id:"client_id",
17  client_secret:"your client secret",
18  serveruri: "http://localhost:4000",
19  uirui: "http://localhost:3000",
20  redirectURL: "http://localhost:4000/auth/creds",
21  access_token: 'your access token',
22 refresh_token: 'your refresh token',
23  
24}
25
26const oauth2Client = new google.auth.OAuth2(
27  creds.client_id,
28  creds.client_secret,
29   creds.redirectURL
30);
31const scopes = [
32  'https://mail.google.com/'
33];
34
35
36const sendMail=async()=>{
37  try{
38    // Create the email envelope (transport)
39    const transport = nodemailer.createTransport({
40     service: 'gmail',
41     auth: {
42       type: 'OAuth2',
43       user:creds.client_email,
44       clientId: creds.client_id,
45       clientSecret: creds.client_secret,
46       accessToken: creds.access_tokenfb,
47       
48     },
49   });
50   
51   // Create the email options and body 
52   // ('email': user's email and 'name': is the e-book the user wants to receive)
53   const mailOptions = {
54     from: `FRONT <${creds.client_email}>`,
55     to: "email2@gmail.com",
56     subject: `[FRONT]- Here is your e-Book!`,
57     html: `Enjoy learning!`,
58 
59   };
60   
61   // Set up the email options and delivering it
62   const result = await transport.sendMail(mailOptions);
63   console.log("success    === ",result) 
64   return result;
65   
66   } catch (error) {
67  console.log("error sendng mail    === ",error)   
68   return error;
69   }
70}
71
72//default auth route
73router.get('/',async(req,res)=>{
74 console.log("hit auth route")
75res.send("auth route")
76
77})
78
79
80
81//route to handle api client authentication
82router.get('/google',async(req,res)=>{
83
84const url = oauth2Client.generateAuthUrl({
85  // 'online' (default) or 'offline' (gets refresh_token)
86  access_type: 'offline',
87 // If you only need one scope you can pass it as a string
88  scope: scopes
89})
90console.log("url returned ======= ",url)
91//url returned by google to redirect us to the login consent page // page
92if(url){
93// render an ejs view with a button that redirects to the url
94res.render('authorize',{url:url})
95}
96})
97
98
99//redirect route that receives the authentication creds and swaps them for access and refresh token 
100
101router.get('/creds',async(req,res)=>{
102
103const code = req.query.code
104console.log("query ==== ",code)
105//returns access and refresh tokens
106const {tokens} = await oauth2Client.getToken(code)
107console.log("query token response==== ",tokens)
108//perform save to firestore or your db of choice here
109
110//authenticate oauthclient
111oauth2Client.setCredentials(tokens);
112
113//render a view to indicate completion
114res.render('done')
115
116})
117
118
119
120
121router.get('/mail',async(req,res)=>{
122let email=""
123await sendMail().then((result)=>email=result).catch((err)=>email=err)
124console.log("email sent or error    === ",email)
125
126await res.json(email)  
127
128
129})
130
131
132module.exports=router