First commit

api/modules/requestHandler.js

@@ -0,0 +1,54 @@
+import rateLimit from 'express-rate-limit';
+import slowDown from 'express-slow-down';
+import http from 'http';
+import os from 'os';
+
+const requestLimiter = rateLimit({
+	windowMs: 60 * 1000,
+	max: 5,
+	standardHeaders: true,
+	legacyHeaders: false,
+	message: 'Too many requests from this IP, please try again later',
+});
+
+const speedLimiter = slowDown({
+	windowMs: 60 * 1000,
+	delayAfter: 5,
+	delayMs: (hits) => hits * 100,
+});
+
+function checkSystemLoad(req, res, next) {
+	const load = os.loadavg()[0];
+	const cores = os.cpus().length;
+	const threshold = cores * 0.7;
+
+	if (load > threshold) {
+		return respondWithStatus(res, 503, 'API Unavailable - System Overloaded!');
+	}
+
+	return next();
+}
+
+function respondWithStatus(res, statusCode, message) {
+	const response = { status: statusCode, message: message };
+	if (statusCode >= 400 && statusCode <= 599) {
+		response.error = http.STATUS_CODES[statusCode];
+	}
+	return res.status(statusCode).json(response);
+}
+
+function respondWithStatusJSON(res, statusCode, JSON) {
+	const response = { status: statusCode, JSON };
+	if (statusCode >= 400 && statusCode <= 599) {
+		response.error = http.STATUS_CODES[statusCode];
+	}
+	return res.status(statusCode).json(response);
+}
+
+export {
+	requestLimiter,
+	speedLimiter,
+	checkSystemLoad,
+	respondWithStatus,
+	respondWithStatusJSON,
+};