Fastify hooks on the route opts type

Prerequisites

• I have written a descriptive issue title
• I have searched existing issues to ensure the feature has not already been requested

🚀 Feature Proposal

This would allow to simplify the custom request properties example on the readme https://github.com/fastify/fastify-nextjs#custom-properties-on-the-request-object

Instead of needing a register with a prefix, you could add the hook on the .next call directly.

fastify.next('/hello', {
  onRequest: function (request, reply, done) {
    // define a custom property on the request
    request.raw.customProperty = { hello: "world" }
    // OR make the instance of fastify-redis available in the request
    request.raw.redisInstance = instance.redis
    done()
  }
});

Motivation

Currently it is not possible (as far as I can tell?) to apply a hook to the routes handled by the next plugin only, unless there is a route prefix like in the readme example.

Example

fastify.next('*', {
  {
    onRequest: () => {
      // hook contents here
    },
  },
});

[mcollina]

A PR would be highly welcomed.

[stefee]

I found that encapsulating the .next(‘*’) in a plugin (with .register) fixed my issue - now the onRequest is only called for requests handled by Next.js.

I also have an early return in the onRequest handler for public static files:

const PUBLIC_FILE_PATHS = [
  '/_next/',
  '/static/',
  '/favicon.ico',
  '/robots.txt',
];

      const { url } = request;
      const isPublicFile = PUBLIC_FILE_PATHS.some((path) =>
        url.startsWith(path),
      );

      if (isPublicFile) {
        return;
      }

I was going to try to find a better way of doing this - maybe just disabling static file serving in the plugin and doing it with a separate plugin instead.