Using Google-Oauth2 for creating User

Author: Krishna Kant

config/passport-google-oauth2-strategy.js

@@ -0,0 +1,45 @@
+const passport = require("passport");
+const googleStrategy = require("passport-google-oauth").OAuth2Strategy;
+const crypto = require("crypto");
+// const { promisify } = require("util");
+const User = require("../models/user");
+
+passport.use(
+  new googleStrategy(
+    {
+      clientID:
+        "122142816625-mnuj9cb21fdd9u1voer990b4macuoe8t.apps.googleusercontent.com",
+      clientSecret: "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",
+      callbackURL: "http://localhost:3000/users/auth/google/callback",
+    },
+    async function (accessToken, refreshToken, profile, done) {
+      try {
+        const user = await User.findOne({
+            email: profile.emails[0].value,
+          });
+
+        // console.log(accessToken, refreshToken);
+        // console.log(profile);
+
+        if (user) {
+          // If Found return from request
+          return done(null, user);
+        } else {
+          // if not found, create the user and set it as req.user
+          const newUser = User.create({
+            name: profile.displayName,
+            email: profile.emails[0].value,
+            password: crypto.randomBytes(20).toString("hex"),
+          });
+
+          return done(null, newUser);
+        }
+      } catch (err) {
+        console.log("error in google strategy-passport", err);
+        return done(err);
+      }
+    }
+  )
+);
+
+module.exports = passport;

index.js

@@ -12,6 +12,8 @@ const session = require("express-session");
 const passport = require("passport");
 const passportLocal = require("./config/passport-local-strategy");
 const passportJWT = require('./config/passport-jwt-strategy');
+const passportGoogle = require('./config/passport-google-oauth2-strategy');
+
 const MongoStore = require("connect-mongo");
 const sassMiddleware = require("node-sass-middleware");
 const flash = require('connect-flash');

package-lock.json

@@ -14,6 +14,7 @@
     "connect-flash": "^0.1.1",
     "connect-mongo": "^5.0.0",
     "cookie-parser": "^1.4.6",
+    "crypto": "^1.0.1",
     "ejs": "^3.1.9",
     "express": "^4.18.2",
     "express-ejs-layouts": "^2.5.1",
@@ -24,6 +25,7 @@
     "node-sass-middleware": "^1.0.1",
     "nodemon": "^2.0.22",
     "passport": "^0.6.0",
+    "passport-google-oauth": "^2.0.0",
     "passport-jwt": "^4.0.1",
     "passport-local": "^1.0.0"
   }

package.json

@@ -23,4 +23,10 @@ router.post('/create-session', passport.authenticate(
 
 router.get('/sign-out', userController.destroySession);
 
+
+// For Google Oauth Strategy
+router.get('/auth/google', passport.authenticate('google', {scope: ['profile', 'email']}));
+
+router.get('/auth/google/callback', passport.authenticate('google', {failureRedirect: '/users/sign-in'}), userController.createSession);
+
 module.exports = router;

routes/users.js

@@ -4,4 +4,8 @@
     <input type="email" name="email" placeholder="Enter email" required>
     <input type="password" name="password" placeholder="Enter password" required>
     <button type="submit">Sing In</button>
-</form>
+</form>
+
+<p>
+    <a href="/users/auth/google">Google Sign In / Sign Up</a>
+</p>

views/user_sign_in.ejs

@@ -6,4 +6,8 @@
     <input type="password" name="password" placeholder="Enter password" required>
     <input type="password" name="confirm_password" placeholder="Confirm password" required>
     <button type="submit">Sing Up</button>
-</form>
+</form>
+
+<p>
+    <a href="/users/auth/google">Google Sign In / Sign Up</a>
+</p>