Rate limiting:

• Rate limit middleware to limit access.
• Everytime a user sends a request to the server, ipaddress of the user is the key and the number of times visited is increased by one.
• This function also sets of a callback function which gets triggered after timelimit(second parameter) seconds and reduces the number of times visited by one.
• So we effectively keep the ipaddress and number of requests in the last timelimit seconds window.
• If it is greater than the requestlimits(firstparameter), we send an error message.

Usage:

• const ratelimiter = require("rate-limit-express");
• app.use(ratelimiter.ratelimit(5, 10));
• app is your Express app and first parameter is timelimit and second parameter is access limit