Using subdomains in NestJS with Fastify Adapter?

Question

The docs state that Fastify doesn't support nested routers, however they do support a Route Config which in theory should allow me to use constraints to limit a route to a sub domain, such as the following:

import { Controller, Get } from '@nestjs/common';
import { AppService } from './app.service';
import { RouteConfig } from '@nestjs/platform-fastify';

@Controller()
export class AppController {
  constructor(private readonly appService: AppService) {}

  @RouteConfig({
    constraints: { host: 'admin.example.com' },
  })
  @Get()
  getHello(): string {
    return this.appService.getHello();
  }
}

This doesn't work in practice however, and seems to resolve to the same route regardless of top-level or subdomain resolution.

Answer 1

My answer might be a bit late, but my PR to add this feature was merged only today.

In previous versions of @nestjs/platform-fastify (< v10.3) you wouldn't be able to use @RouteConfig as that only implements Fastitfy's route config feature.

If possible, update your @nestjs/platform-fastify to a recent version (>= v10.3.0) and use @RouteConstraints decorator:

import { Controller, Get } from '@nestjs/common';
import { AppService } from './app.service';
import { RouteConstraints } from '@nestjs/platform-fastify';

@Controller()
export class AppController {
  constructor(private readonly appService: AppService) {}

  @RouteConstraints({
    host: 'admin.example.com',
  })
  @Get()
  getHello(): string {
    return this.appService.getHello();
  }
}

References:

• https://github.com/nestjs/nest/releases/tag/v10.3.0
• https://github.com/fastify/fastify/releases/tag/v4.25.0
• https://github.com/nestjs/docs.nestjs.com/pull/2926

Thank you for pointing to this issue and giving me an opportunity to do some OSS contributions :)