koa-ratelimiter

Rate limiter middleware for koa.

Installation

$ npm install koa-ratelimiter

Usage

The library exports 3 things:

• default: a factory accepting a ratelimiter adapter and which a function with options to build the middleware
• redisRateLimit: an helper function returning a middleware initialized with a redisAdapter
• memoryRateLimit: an helper function returning a middleware initialized with a memoryAdapter

redisRateLimit

Options

• db redis connection instance
• max max requests within duration [2500]
• duration of limit in milliseconds [3600000]
• id id to compare requests [ip]

Example

var ratelimiter = require('koa-ratelimiter').redisRateLimit;
var redis = require('redis');
var koa = require('koa');
var app = koa();

// apply rate limit

app.use(ratelimiter({
  db: redis.createClient(),
  duration: 60000,
  max: 100,
  id: function (context) {
    return context.ip;
  }
}));

// response middleware

app.use(function *(){
  this.body = 'Stuff!';
});

app.listen(3000);
console.log('listening on port 3000');

memoryRateLimit

This mode uses the memoryAdapter of node-ratelimiter. It should only be used in development.

Options

• max max requests within duration [2500]
• duration of limit in milliseconds [3600000]
• id id to compare requests [ip]

Example

var ratelimiter = require('koa-ratelimiter').memoryRateLimit;
var koa = require('koa');
var app = koa();

// apply rate limit

app.use(ratelimiter({
  duration: 60000,
  max: 100,
  id: function (context) {
    return context.ip;
  }
}));

// response middleware

app.use(function *(){
  this.body = 'Stuff!';
});

app.listen(3000);
console.log('listening on port 3000');

nullRateLimit

This mode uses the nullAdapter of node-ratelimiter. It should only be used for testing purposes.

Example

var ratelimiter = require('koa-ratelimiter').nullRateLimit;
var koa = require('koa');
var app = koa();

// apply rate limit

app.use(ratelimiter({}));

// response middleware

app.use(function *(){
  this.body = 'Stuff!';
});

app.listen(3000);
console.log('listening on port 3000');

custom adapter

To learn more about what a custom adapter should be, please refer to the ratelimiter documentation

Options

• max max requests within duration [2500]
• duration of limit in milliseconds [3600000]
• id id to compare requests [ip]

Example

var ratelimiter = require('koa-ratelimiter');
var koa = require('koa');
var app = koa();
var myCustomAdapter = require('./myCustomAdapter');
// apply rate limit

app.use(ratelimiter(myCustomAdapter)({
  duration: 60000,
  max: 100,
  id: function (context) {
    return context.ip;
  }
}));

// response middleware

app.use(function *(){
 this.body = 'Stuff!';
});

app.listen(3000);
console.log('listening on port 3000');

Responses

Example 200 with header fields:

HTTP/1.1 200 OK
X-Powered-By: koa
X-RateLimit-Limit: 100
X-RateLimit-Remaining: 99
X-RateLimit-Reset: 1384377793
Content-Type: text/plain; charset=utf-8
Content-Length: 6
Date: Wed, 13 Nov 2013 21:22:13 GMT
Connection: keep-alive

Stuff!

Example 429 response:

HTTP/1.1 429 Too Many Requests
X-Powered-By: koa
X-RateLimit-Limit: 100
X-RateLimit-Remaining: 0
X-RateLimit-Reset: 1384377716
Content-Type: text/plain; charset=utf-8
Content-Length: 39
Retry-After: 7
Date: Wed, 13 Nov 2013 21:21:48 GMT
Connection: keep-alive

Rate limit exceeded, retry in 8 seconds

License

MIT