rateLimitMiddleware.ts

import { Request, Response, NextFunction } from 'express';
import { getClientIp } from '../utils/getIpAddress';
import RedisDatabase from '../db/redisConnection';

export default (req: Request, res: Response, next: NextFunction) => {
	const redis_client = new RedisDatabase().connectDB();
	const ipAddress = getClientIp(req);

	redis_client
		.multi()
		.set([ipAddress, 0, 'EX', 3600, 'NX']) // NX -> 只有 key 不存在才會設立
		.incr(ipAddress)
		.ttl(ipAddress)
		.exec((err: any, replies: any) => {
			if (err) {
				return res.status(500).send(err.message);
			}
			const requestCount = replies[1];
			res.set({
				'X-RateLimit-Remaining': 1000 - requestCount,
				'X-RateLimit-Reset': replies[2]
			});

			if (requestCount > 1000) {
				return res.status(429).send('You sent too many requests in an hour!')
			}

			return next()
		})
}