express-light-limiter

Smart express lightweight middleware for rate-limiting based on Zones to prevent memory leaks

Install

• Install module from npm:

$ npm install --save express-light-limiter

Usage

import express from 'express';
import limiter from 'express-light-limiter';

let app = express();

const limiterConfig = {
  quantum: 10 * 1000, // 10 seconds
  maxRequestsPerQuantum: 20, // requests restriction is 20 for a single quantum
  lookup: 'connection.remoteAddress', // it can be an array or a function
  error: new HttpError('Too many requests', 429) // your custom error object
};

app.get('/api/action', [ limiter(limiterConfig) ], function (req, res) {
  res.send(200, 'ok')
})

API options

limiter(options)

• lookup: Function|String|Array.<String> value lookup on the request object. Can be a single value, array or function. See examples below. Default is connection.remoteAddress.

• quantum: Number unit of time for counting requests. Default is 5 * 1000 (5 sec).

• maxRequestsPerQuantum: Number number of requests that allowed in a single quantum of time.

• error: Object optional param allowing throw a custom error in next function

Examples

// limit by IP address
limiter({
  ...
  lookup: 'connection.remoteAddress'
  ...
})

// or if you are behind a trusted proxy (like nginx)
limiter({
  lookup: 'headers.x-forwarded-for'
})

// by user (assuming a user is logged in with a valid id)
limiter({
  lookup: 'user.id'
})

// limit users by their id or IP (if user's id is not available)
limiter({
  lookup: ['user.id', 'connection.remoteAddress']
})

// with a function
limiter({
  lookup(req) {
    return req.connection.remoteAddress || req.user.id || req.ip;
  }
})

Separate methods

// limiter with default options
app.get('/user', limiter(), (req, res, next) => {
  User.findOne(req.user.id).then(result => {
    res.json(result);
  }).catch(next);
});

app.get('/news', limiter({ quantum: 60 * 1000, maxRequestsPerQuantum: 120 }), (req, res, next) => {
  User.findAll().then(result => {
    res.json(result);
  }).catch(next);
})

License

MIT © 2016 Alexander Belov