Dynamic callback for Google and Facebook login

api/passport/facebook.js

@@ -3,27 +3,33 @@ const { Strategy: FacebookStrategy } = require('passport-facebook');
 const config = require('../../config');
 const UserController = require('../controllers/user');
 
+const urljoin = require('url-join');
+
 const FBStrategy = {
   clientID: process.env.FACEBOOK_APP_ID,
   clientSecret: process.env.FACEBOOK_APP_SECRET,
-  callbackURL: process.env.FACEBOOK_CALLBACK_URL,
   profileFields: ['id', 'emails', 'name', 'displayName', 'gender', 'picture']
 };
 
 passport.use(new FacebookStrategy(FBStrategy, UserController.facebookLogin));
 
 const configureFacebookStrategy = app => {
-  app.get(
-    '/login/facebook',
+  app.get('/login/facebook', (req, res, next) => 
     passport.authenticate('facebook', {
       session: false,
-      scope: config.facebook.SCOPE
-    })
+      scope: config.facebook.SCOPE,
+      callbackURL: urljoin(req.domain, config.facebookCallbackPath)
+    })(req, res, next)
   );
 
   app.get(
     '/login/facebook/callback',
-    passport.authenticate('facebook', { session: false }),
+    (req, res, next) => 
+      passport.authenticate('facebook', {
+        session: false,
+        callbackURL: urljoin(req.domain, config.facebookCallbackPath)
+      })(req, res, next)
+    ,
     (req, res) => {
       res.json(req.user);
     }

api/passport/google.js

@@ -3,23 +3,24 @@ const { OAuth2Strategy: GoogleStrategy } = require('passport-google-oauth');
 const config = require('../../config');
 const UserController = require('../controllers/user');
 
+const urljoin = require('url-join');
+
 const GoogleStrategyConfig = {
   clientID: config.google.APP_ID,
-  clientSecret: config.google.APP_SECRET,
-  callbackURL: config.google.CALLBACK_URL
+  clientSecret: config.google.APP_SECRET
 };
 
 passport.use(
   new GoogleStrategy(GoogleStrategyConfig, UserController.googleLogin)
 );
 
 const configureGoogleStrategy = app => {
-  app.get(
-    '/login/google',
+  app.get('/login/google', (req, res, next) => 
     passport.authenticate('google', {
       session: false,
-      scope: config.google.SCOPE
-    })
+      scope: config.google.SCOPE,
+      callbackURL: urljoin(req.domain, config.googleCallbackPath)
+    })(req, res, next)
   );
 
   // GET /login/google/callback
@@ -29,7 +30,13 @@ const configureGoogleStrategy = app => {
   //   which, in this example, will redirect the user to the home page.
   app.get(
     '/login/google/callback',
-    passport.authenticate('google', { failureRedirect: '/', session: false }),
+    (req, res, next) => 
+      passport.authenticate('google', {
+        callbackURL: urljoin(req.domain, config.googleCallbackPath),
+        failureRedirect: '/',
+        session: false
+      })(req, res, next)
+    ,
     (req, res) => {
       res.json(req.user);
     }

app.js

@@ -94,6 +94,11 @@ swaggerTools.initializeMiddleware(swaggerConfig, async function (middleware) {
 
   app.use(middleware.swaggerUi());
 
+  app.use((req, res, next) => {
+    req.domain = req.headers.referer || 'https://app.cboard.io/';
+    next();
+  });
+
   Facebook.configureFacebookStrategy(app);
   Google.configureGoogleStrategy(app);
   GoogleToken.configureGoogleTokenStrategy(app);

config/index.js

@@ -5,7 +5,9 @@ const production = require('./env/production');
 
 const defaults = {
   host: process.env.HOST || 'mongodb',
-  port: process.env.PORT || 8100
+  port: process.env.PORT || 8100,
+  googleCallbackPath: 'login/google/callback',
+  facebookCallbackPath: 'login/facebook/callback'  
 };
 
 function getConfig() {