fastify-http-proxy

fastify-http-proxy

Proxy your http requests to another server, with hooks. This fastify plugin forward all the request received with a given prefix (or none) to an upstream. All Fastify hooks are still applied.

fastify-http-proxy is built on top of fastify-reply-from, which enables you for single route proxying.

This plugin can be used in a variety of circumstances, for example if you have to proxy an internal domain to an external domain (useful to avoid CORS problems) or to implement your own API gateway for a microservices architecture.

Requirements

Fastify 2.x. See this branch and related versions for Fastify 1.x compatibility.

Install

npm i fastify-http-proxy fastify

Example

const Fastify = require('fastify')
const server = Fastify()

server.register(require('fastify-http-proxy'), {
  upstream: 'http://my-api.example.com',
  prefix: '/api', // optional
  http2: false // optional
})

server.listen(3000)

This will proxy any request starting with /api to http://my-api.example.com. For instance http://localhost:3000/api/users will be proxied to http://my-api.example.com/users.

If you want to have different proxies on different prefixes in you can register multiple instances of the plugin as shown in the following snippet:

const Fastify = require('fastify')
const server = Fastify()
const proxy = require('fastify-http-proxy')

server.register(proxy, {
  upstream: 'http://my-api.example.com',
  prefix: '/api', // optional
  http2: false // optional
})

server.register(proxy, {
  upstream: 'http://single-signon.example.com/auth',
  prefix: '/auth', // optional
  http2: false // optional
})

server.listen(3000)

Notice that in this case it is important to use the prefix option to tell the proxy how to properly route the requests across different upstreams.

For other examples, see example.js.

Options

This fastify plugin supports all the options of fastify-reply-from plus the following.

Note that this plugin is fully encapsulated, and non-JSON payloads will be streamed directly to the destination.

upstream

An URL (including protocol) that represents the target server to use for proxying.

prefix

The prefix to mount this plugin on. All the requests to the current server starting with the given prefix will be proxied to the provided upstream.

The prefix will be removed from the URL when forwarding the HTTP request.

rewritePrefix

Rewrite the prefix to the specified string. Default: ''.

preHandler

A preHandler to be applied on all routes. Useful for performing actions before the proxy is executed (e.g. check for authentication).

config

An object accessible within the preHandler via reply.context.config. See Config in the Fastify documentation for information on this option. Note: this is merged with other configuration passed to the route.

replyOptions

Object with reply options for fastify-reply-from.

Benchmarks

The following benchmarks where generated on a Macbook 2018 with i5 and 8GB of RAM:

Framework	req/sec
express-http-proxy	878.4
http-proxy	3837
fastify-http-proxy	4205
fastify-http-proxy (with undici)	6235.6

The results where gathered on the second run of autocannon -c 100 -d 5 URL.

TODO

• Generate unique request ids and implement request tracking
• Perform validations for incoming data

License

MIT