Dynamic rate-limiting middleware in Express

To create a dynamic rate-limiting middleware in Express that can be used at different levels (controller, app, router), you can use the express-rate-limit package. This middleware can be configured dynamically based on the parameters you pass.

Here's an example of a custom rate-limiting middleware that can be used at different levels in Express:

First, install the express-rate-limit package:

npm install express-rate-limit

Then, create a module that exports a function to generate the rate-limiting middleware dynamically:

// rateLimitMiddleware.js

const rateLimit = require("express-rate-limit");

function createRateLimitMiddleware(options) {
  // You can configure the rate limit dynamically using the options parameter
  const limiter = rateLimit({
    windowMs: options.windowMs || 60 * 1000, // 1 minute by default
    max: options.max || 100, // 100 requests per windowMs by default
    message: options.message || "Too many requests, please try again later."
  });

  return limiter;
}

module.exports = createRateLimitMiddleware;

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Next, in your Express application, you can use this dynamically created rate-limiting middleware in different levels:

At the App Level:

const express = require("express");
const app = express();
const createRateLimitMiddleware = require("./rateLimitMiddleware");

// Apply rate limiting for the entire app
const appLevelRateLimiter = createRateLimitMiddleware({
  windowMs: 60 * 60 * 1000, // 1 hour
  max: 1000, // 1000 requests per hour
});

app.use(appLevelRateLimiter);
// Other app configurations and routes

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At the Router/Route Level:

const express = require("express");
const router = express.Router();
const createRateLimitMiddleware = require("./rateLimitMiddleware");

// Apply rate limiting for a specific router
const routerLevelRateLimiter = createRateLimitMiddleware({
  windowMs: 60 * 1000, // 1 minute
  max: 30, // 30 requests per minute
});

router.use(routerLevelRateLimiter);
// Define router paths and their respective handlers

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At the Controller Level (per route):

const express = require("express");
const router = express.Router();
const createRateLimitMiddleware = require("./rateLimitMiddleware");

// Apply rate limiting for specific routes/controllers
const specificRouteRateLimiter = createRateLimitMiddleware({
  windowMs: 60 * 1000, // 1 minute
  max: 10, // 10 requests per minute
});

router.get("/specific-route", specificRouteRateLimiter, (req, res) => {
  // Controller logic for the specific route
});

This setup allows you to dynamically configure rate-limiting based on your specific needs at different levels within your Express application. Adjust the parameters in the options object passed to createRateLimitMiddleware to fit your requirements.