revert: allow user to redirect after signin (#40160)

This reverts commit a7eba00690.

api-server/server/middlewares/add-return-to.js

@@ -0,0 +1,37 @@
+const pathsOfNoReturn = [
+  'link',
+  'auth',
+  'login',
+  'logout',
+  'signin',
+  'signup',
+  'fonts',
+  'favicon',
+  'js',
+  'css'
+];
+
+const pathsAllowedList = ['challenges', 'map', 'commit'];
+
+const pathsOfNoReturnRegex = new RegExp(pathsOfNoReturn.join('|'), 'i');
+const pathsAllowedRegex = new RegExp(pathsAllowedList.join('|'), 'i');
+
+export default function addReturnToUrl() {
+  return function(req, res, next) {
+    // Remember original destination before login.
+    var path = req.path.split('/')[1];
+
+    if (
+      req.method !== 'GET' ||
+      pathsOfNoReturnRegex.test(path) ||
+      !pathsAllowedRegex.test(path) ||
+      /hot/i.test(req.path)
+    ) {
+      return next();
+    }
+    req.session.returnTo = req.originalUrl.includes('/map')
+      ? '/'
+      : req.originalUrl;
+    return next();
+  };
+}