Fastify-net-acl NPM

fastify-net-acl

Fastify plugin that restricts access according to IP address/subnet allow and block lists.

Install

npm i fastify-net-acl

Usage

Blocking

Block IP address:

fastify.register(require('fastify-net-acl'), {
  blockList: '1.2.3.4'
})

Block multiple IP addresses:

fastify.register(require('fastify-net-acl'), {
  blockList: [
    '1.2.3.4',
    '2.3.4.5'
  ]
})

Block subnet:

fastify.register(require('fastify-net-acl'), {
  blockList: '1.2.3.4/24'
})

Block a bunch of stuff:

fastify.register(require('fastify-net-acl'), {
  blockList: [
    '::1',
    '4.3.2.1',
    '4.2.3.4',
    '1.2.3.4/24',
    '2.3.4.5/16'
  ]
})

Allowing

Only allow 1 IP address:

fastify.register(require('fastify-net-acl'), {
  allowList: '1.2.3.4'
})

Only allow 1 subnet:

fastify.register(require('fastify-net-acl'), {
  allowList: '1.2.3.4/24'
})

Only allow specified IP addresses and subnets:

fastify.register(require('fastify-net-acl'), {
  allowList: [
    '::1',
    '2.3.4.5',
    '1.2.3.4/24'
  ]
})

Route specific rules

Note: you must await the plugin registration so the decorator function is accessible for the route definition.

await fastify.register(require('fastify-net-acl'), {
  blockList: '1.2.3.4/24',
  global: false
})

const onRequest = fastify.createNetAclRequestHandler()

fastify.get('/has-blocking', { onRequest }, (req, reply) => {})
fastify.get('/no-blocking', (req, reply) => {})

Use multiple allow/block lists:

await fastify.register(require('fastify-net-acl'), {
  allowList: {
    foo: '1.2.3.4/24'
  },

  blockList: {
    bar: '2.3.4.5/24'
  },

  global: false
})

{
  const onRequest = fastify.createNetAclRequestHandler('allow:foo')
  fastify.get('/foo', { onRequest }, (req, reply) => {})
}

{
  const onRequest = fastify.createNetAclRequestHandler('block:bar')
  fastify.get('/bar', { onRequest }, (req, reply) => {})
}

fastify.get('/no-blocking', (req, reply) => {})

Reference

This plugin decorates the fastify instance with allowList and/or blockList, depending on which properties are specified in options. Both are instances of net.BlockList and determine which IP addresses/subnets are allowed or blocked, respectively.

Note: fastify-net-acl requires Node >= 15.0.0 since net.Blocklist was introduced in 15.0.0.

The options object has the following properties. Either allowList xor blockList must be specified if global is true. Both may be specified if global is false since you may want to use different allow/block lists on different routes.

allowList is an array of IPv4/IPv6 addresses and/or subnets in CIDR format indicating which IPs should be allowed
blockList is an array of IPv4/IPv6 addresses and/or subnets in CIDR format indicating which IPs should be blocked
errorCode is the HTTP status code when an IP is blocked/not allowed (default: 403)
errorMessage is the status message when an IP is blocked/not allowed (default: generic status message for errorCode)
global is a boolean indicating whether the ACL applies globally, i.e. for all routes (default: true)