koa-ratelimit

Rate limiter middleware for koa.

Table of Contents

• Installation
• Example
  • With a Redis driver
  • With a memory driver
• Options
• Responses
• License

Installation

npm install koa-ratelimit

Example

With a Redis driver

const Koa = require('koa');
const ratelimit = require('koa-ratelimit');
const Redis = require('ioredis');
const app = new Koa();

// apply rate limit
app.use(ratelimit({
  driver: 'redis',
  db: new Redis(),
  duration: 60000,
  errorMessage: 'Sometimes You Just Have to Slow Down.',
  id: (ctx) => ctx.ip,
  headers: {
    remaining: 'Rate-Limit-Remaining',
    reset: 'Rate-Limit-Reset',
    total: 'Rate-Limit-Total'
  },
  max: 100,
  disableHeader: false,
  whitelist: (ctx) => {
    // some logic that returns a boolean
  },
  blacklist: (ctx) => {
    // some logic that returns a boolean
  },
  onLimited: (ctx) => {
    // optional function to run when a user is rate limited
  }
}));

// response middleware
app.use(async (ctx) => {
  ctx.body = 'Stuff!';
});

// run server
app.listen(
  3000,
  () => console.log('listening on port 3000')
);

With a memory driver

const Koa = require('koa');
const ratelimit = require('koa-ratelimit');
const app = new Koa();

// apply rate limit
const db = new Map();

app.use(ratelimit({
  driver: 'memory',
  db: db,
  duration: 60000,
  errorMessage: 'Sometimes You Just Have to Slow Down.',
  id: (ctx) => ctx.ip,
  headers: {
    remaining: 'Rate-Limit-Remaining',
    reset: 'Rate-Limit-Reset',
    total: 'Rate-Limit-Total'
  },
  max: 100,
  disableHeader: false,
  whitelist: (ctx) => {
    // some logic that returns a boolean
  },
  blacklist: (ctx) => {
    // some logic that returns a boolean
  }
}));

// response middleware
app.use(async (ctx) => {
  ctx.body = 'Stuff!';
});

// run server
app.listen(
  3000,
  () => console.log('listening on port 3000')
);

Options

• driver memory or redis [redis]
• db redis connection instance or Map instance (memory)
• duration of limit in milliseconds [3600000]
• errorMessage custom error message
• id id to compare requests [ip]
• namespace prefix for storage driver key name [limit]
• headers custom header names
• max max requests within duration [2500]
• disableHeader set whether send the remaining, reset, total headers [false]
• remaining remaining number of requests ['X-RateLimit-Remaining']
• reset reset timestamp ['X-RateLimit-Reset']
• total total number of requests ['X-RateLimit-Limit']
• whitelist if function returns true, middleware exits before limiting
• blacklist if function returns true, 403 error is thrown
• throw call ctx.throw if true

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 © Koa.js contributors