Feature/delay middleware (#146)

* add delay middleware to login and signin routes

* Different delay for sendStatus and json

---------

Co-authored-by: Markus Frindt <m.frindt@cognigy.com>

lib/middleware.js

@@ -0,0 +1,32 @@
+const logger = require('./logger');
+
+function delayLoginMiddleware(req, res, next) {
+  if (req.path.includes('/login') || req.path.includes('/signin')) {
+    const min = 200;
+    const max = 1000;
+    /* Random delay between 200 - 1000ms */
+    const sendStatusDelay = Math.floor(Math.random() * (max - min + 1)) + min;
+
+    /* the res.json take longer, we decrease the max delay slightly to 0-800ms */
+    const jsonDelay = Math.floor(Math.random() * 800);
+    logger.debug(`delayLoginMiddleware: sendStatus ${sendStatusDelay} - json ${jsonDelay}`);
+    const sendStatus = res.sendStatus;
+    const json = res.json;
+
+    res.sendStatus = function(status) {
+      setTimeout(() => {
+        sendStatus.call(res, status);
+      }, sendStatusDelay);
+    };
+    res.json = function(body) {
+      setTimeout(() => {
+        json.call(res, body);
+      }, jsonDelay);
+    };
+  }
+  next();
+}
+
+module.exports = {
+  delayLoginMiddleware
+};