feat(server/middlewares): Show signin to com users (#15569)

* feat(server/middlewares): Show signing to com users

When a signed in user is redirected from the com to the org (with the ref=com in the query) they will be
redirected to the signin page with a message letting them know why they are signed out

* feat(server): Redirected user see's special sigin page

server/boot/user.js

@@ -143,6 +143,7 @@ module.exports = function(app) {
     res.redirect(301, '/signout');
   });
   router.get('/signin', getSignin);
+  router.get('/signin-com', getSigninCom);
   router.get('/signout', signout);
   router.get('/forgot', getForgot);
   router.post('/forgot', postForgot);
@@ -225,6 +226,15 @@ module.exports = function(app) {
     });
   }
 
+  function getSigninCom(req, res) {
+    if (req.user) {
+      return res.redirect('/');
+    }
+    return res.render('account/signin-com', {
+      title: 'Sign in to freeCodeCamp'
+    });
+  }
+
   function signout(req, res) {
     req.logout();
     req.flash('success', {

server/middleware.json

@@ -39,6 +39,7 @@
   },
   "routes:before": {
     "express-flash": {},
+    "./middlewares/coming-from-com": {},
     "helmet#xssFilter": {},
     "helmet#noSniff": {},
     "helmet#frameguard": {},

server/middlewares/coming-from-com.js

@@ -0,0 +1,11 @@
+export default () => {
+  return function comingFromCom(req, res, next) {
+    if (
+      !req.user &&
+      req.query.ref === 'com'
+    ) {
+      return res.redirect('/signin-com');
+    }
+    return next();
+  };
+};

server/views/account/signin-com.jade

@@ -0,0 +1,16 @@
+extends ../layout
+block content
+    .text-center
+        h2 Welcome to our new freecodecamp.ORG address.
+        h4 We sent you here from our old freecodecamp.COM address.
+        h4 Please sign in again to continue coding. Thanks!
+        .spacer
+        a.btn.btn-lg.btn-block.btn-social.btn-primary(href='/email-signin')
+            i.fa.fa-envelope
+            | Sign in with Email
+        a.btn.btn-lg.btn-block.btn-social.btn-github(href='/auth/github')
+            i.fa.fa-github
+            | Sign in with GitHub
+        .button-spacer
+        p
+            a(href="/deprecated-signin") Click here if you previously signed in using a different method.