toa-ratelimit

Smart rate limiter module for toa.

Requirements

• Redis 2.8+ with thunk-redis client

Installation

npm install toa-ratelimit

Example

const Toa = require('toa')
const ratelimit = require('toa-ratelimit')

const app = new Toa()
app.use(ratelimit({
  redis: 6379,
  duration: 10000,
  getId: function () { return this.ip },
  policy: {
    'GET': [3, 5000],
    'GET /test': [3, 5000, 3, 10000],
    '/test': 5
  }
}))
app.use(function () {
  this.body = this.res._headers
})

app.listen(3000, () => console.log('listening on port 3000'))

API

const ratelimit = require('toa-ratelimit')

limiter is a thunk function. It can be used as middleware or module.

Use as a module:

const limiter = ratelimit({
  redis: 6379,
  duration: 10000,
  getId: function () { return this.ip },
  policy: {
    'GET': [3, 5000],
    'POST': [3, 5000, 3, 10000]
  }
})

const app = new Toa()
app.use(function * () {
  // ...
  // Used ratelimit only for `/api/test`:
  if (this.path === '/api/test') yield limiter
})

• options.prefix: Optional, Type: String, redis key namespace, default to LIMIT.

• options.redis: Optional, {Mix}, thunk-redis instance or thunk-redis options

• options.duration: Optional, {Number}, of limit in milliseconds, default to 3600000

• options.getId: Required, {Function}, generate a identifier for requests

• options.policy: Required, {Object}, limit policy

  policy key: It support 3 types: METHOD /path, /path and METHOD. Limiter will try match METHOD /path first, then /path, then METHOD. It means that METHOD /path has highest priority, then fallback to /path and METHOD.

  policy value: If value is a member, it means max count with options.duration. If value is array, it should be a pair of max and duration, support one more pairs.

  The first pair is default limit policy. If someone touch the maximum of default limit, then the next policy will be apply, and so on. So next policy should be stricter than previous one.

  If someone touch the maximum of limit and request again after double current duration time, it will rollback to default policy.

  example policy:

  options.policy = {
    'HEAD': 100,
    'GET': [60, 60000, 30, 60000, 30, 120000],
    'PUT': [40, 60000, 20, 60000, 10, 120000],
    'POST': [40, 60000, 10, 60000],
    'DELETE': [40, 60000, 10, 60000],
    'POST /api/organizations': [10, 60000, 2, 60000],
    'POST /api/projects': [20, 60000, 5, 60000],
    '/api/auth': [10, 60000, 5, 120000],
  }

limiter.remove(context)

Remove context's rate limit data. Return thunk function.

limiter.remove(this).then(function (res) {
  console.log(res) //  1
})

Responses

Example 200 with header fields:

HTTP/1.1 200 OK

Connection:keep-alive
Content-Length:111
Content-Type:application/json; charset=utf-8
Date:Thu, 10 Dec 2015 13:21:55 GMT
X-Powered-By:Toa
X-RateLimit-Limit:3
X-RateLimit-Remaining:2
X-RateLimit-Reset:1449753721

Example 429 with header fields:

HTTP/1.1 429 Too Many Requests

Connection:keep-alive
Content-Length:39
Content-Type:text/html; charset=utf-8
Date:Thu, 10 Dec 2015 13:22:36 GMT
Retry-After:3
X-Powered-By:Toa
X-RateLimit-Limit:3
X-RateLimit-Remaining:-1
X-RateLimit-Reset:1449753759