Unable to use http-proxy for all routes (/*) with @fastify/cors plugin

[kovalenp]

Prerequisites

• [X] I have written a descriptive issue title
• [X] I have searched existing issues to ensure the bug has not already been reported

Fastify version

4.5.3

Plugin version

9.2.1

Node.js version

16.15.1

Operating system

macOS

Operating system version (i.e. 20.04, 11.3, 10)

13.4

Description

I need to allow CORS for my Fastify application. To achieve this I'm using @fastify/cors package with following settings:

    fastify.register(cors, {
      origin: '*',
      methods: ['GET', 'POST'],
      allowedHeaders: ['Content-Type', 'Authorization'],
      credentials: true,
    })

if I register the http-proxy route for something like this:

    .register(require('@fastify/http-proxy'), {
      upstream: 'https://some_url',
    })

I will get an error:

/node_modules/find-my-way/index.js:292
      throw new Error(`Method '${method}' already declared for route '${path}' with constraints '${JSON.stringify(constraints)}'`)
            ^
Error: Method 'OPTIONS' already declared for route '/*' with constraints '{}'
    at Router._on (/node_modules/find-my-way/index.js:292:13)
    at Router.on (/node_modules/find-my-way/index.js:136:10)
    at Object.addNewRoute (/node_modules/fastify/lib/route.js:262:16)
    at Object.route (/node_modules/fastify/lib/route.js:194:19)
    at Object._route [as route] (/node_modules/fastify/fastify.js:268:27)
    at fastifyHttpProxy (/node_modules/@fastify/http-proxy/index.js:291:11)
    at Plugin.exec (/node_modules/avvio/plugin.js:130:19)
    at Boot.loadPlugin (/node_modules/avvio/plugin.js:272:10)
    at processTicksAndRejections (node:internal/process/task_queues:83:21)

Probably because of this part of the lib:

  fastify.route({
    url: '/*',
    method: opts.httpMethods || httpMethods,
    preHandler,
    config: opts.config || {},
    constraints: opts.constraints || {},
    handler

Steps to Reproduce

Register fastify/cors with fastify/fastify-http-proxy for all routes

    fastify
    .register(cors, {
      origin: '*',
      methods: ['GET', 'POST'],
      allowedHeaders: ['Content-Type', 'Authorization'],
      credentials: true,
    })
    .register(require('@fastify/http-proxy'), {
      upstream: 'https://some_url',
    })

Expected Behavior

There is a way to enable cors on all routes for http-proxy plugin

PS:

I tried something like:

.register(require('@fastify/http-proxy'), {
      upstream: process.env.PUBLIC_API_URL,
      onResponse: (request: FastifyRequest, reply: FastifyReply) => {
        reply.header('Access-Control-Allow-Origin', '*')
        reply.header('Access-Control-Allow-Methods', '*')
        reply.header('Access-Control-Allow-Headers', '*')
      },
    })

but it didn't do the trick for me