Error: metatype is not a constructor when using instance of own HTTPS Server class

Question

Good evening, I am playing around with nest and want to achieve an own HTTPS-Server that can be instantiated everywhere in other projects. Right at the beginning I get the following error-message:

TypeError: metatype is not a constructor

… when I init the following HTTPS-Server:

import { Injectable } from '@nestjs/common';
import { NestFactory } from '@nestjs/core';
import { FastifyAdapter, NestFastifyApplication } from '@nestjs/platform-fastify';
import * as fs from 'fs';

@Injectable()
export class HttpsServer {

    constructor() {}

    async bootstrap() {
        const httpsOptions = {
            key: fs.readFileSync('./certs/server.key'),
            cert: fs.readFileSync('./certs/server.cert'),
        };
        const app = await NestFactory.create<NestFastifyApplication>(
            new FastifyAdapter({ https: httpsOptions }),
        );

        await app.listen(443);
    }
}

like this:

import { Logger } from '@nestjs/common';
import { HttpsServer } from 'server-lib';

const logger = new Logger();
const app = new HttpsServer();

app.bootstrap().then(() => {
  logger.log('Bootstrap complete!');
}).catch((error) => {
  logger.log('Bootstrap failed: ', error);
  process.exit(1);
});

Thx for help...

Answer 1

You probably have used an incorrect guard. Check @UseGuards() and use the correct guard for that function.

Answer 2

All Nest applications needs to have a "RootModule" of some sort. With nest new applications this is a AppModule. This class holds the metadata for the server for how to tie everything together and run. What you could probably do is modify your HttpModule's constructor to do something like

export class HttpsServer {

    constructor(private readonly rootModule: Type<any>) {} // Type comes from @nestjs/common

    async bootstrap() {
        const httpsOptions = {
            key: fs.readFileSync('./certs/server.key'),
            cert: fs.readFileSync('./certs/server.cert'),
        };
        const app = await NestFactory.create<NestFastifyApplication>(
            this.rootModule, 
            new FastifyAdapter({ https: httpsOptions }),
        );

        await app.listen(443);
    }
}

So now when you call new HttpServer() you pass in the root module and have everything else already set up. The NestFactory will instantiate the metadata from there properly, and you'll use the FastifyAdapter.

For more information, I suggest you follow the docs overview to get a feeling of how these classes fit together and why they're needed.