👀 Views: 29 💬 Answers: 1 📅 Created: 2025-08-07

express rate-limiting middleware asynchronous node.js JavaScript

I'm trying to debug I've searched everywhere and can't find a clear answer. This might be a silly question, but I'm currently developing an Express application where I need to implement rate limiting. I want to allow regular users to make up to 100 requests per hour and admins to make up to 1,000 requests in the same time frame. I'm using the `express-rate-limit` package for this purpose. I've set up a basic rate limiter like this: ```javascript const rateLimit = require('express-rate-limit'); const userLimit = rateLimit({ windowMs: 60 * 60 * 1000, // 1 hour max: 100, // limit each user to 100 requests per windowMs message: 'Too many requests from this user, please try again later.' }); const adminLimit = rateLimit({ windowMs: 60 * 60 * 1000, max: 1000, message: 'Too many requests from admin, please try again later.' }); app.use((req, res, next) => { if (req.user && req.user.role === 'admin') { adminLimit(req, res, next); } else { userLimit(req, res, next); } }); ``` However, I'm working with an scenario where the rate limit seems to apply only to the first user correctly and then fails for subsequent requests, causing them to be throttled incorrectly. I also noticed that my middleware for checking user roles is asynchronous and returns a Promise, which could be leading to race conditions. When testing, I get the following behavior message when a regular user exceeds the limit: `Too many requests from this user, please try again later.` I also suspect that the admin limit isn't being applied correctly because I see several `Too many requests from admin, please try again later.` errors right after testing the admin account. I've tried wrapping the role-checking logic in a synchronous function, but that hasn't resolved the scenario. Here’s how my user role-checking function looks: ```javascript async function checkUserRole(req, res, next) { // Simulate a DB call to get user role req.user = await getUser(req); next(); } app.use(checkUserRole); ``` Any suggestions on how to correctly implement this rate limiting configuration while ensuring that the user role checks are handled properly? Additionally, are there any best practices I should follow to avoid such issues in the future? Is there a better approach? For context: I'm using Javascript on Ubuntu 20.04. What's the correct way to implement this? Any examples would be super helpful.