use with guard / exceptions filters?

[tal-rofe]

I wonder whether is it possible.
I want to set a global exception filter.

this is my main.ts file:

import { CommandFactory } from 'nest-commander';

import { AppModule } from './app.module';

async function bootstrap() {
	await CommandFactory.run(AppModule);
}

bootstrap();

this is the app.module.ts file

import { Module } from '@nestjs/common';
import { APP_FILTER, APP_GUARD } from '@nestjs/core';

import { AuthCommand } from './commands/auth/auth.command';
import { UnknownExceptionsFilter } from './filters/unknown.filter';
import { ConnnectionGuard } from './guards/connection.guard';
import { ConfigModule } from './modules/config/config.module';

@Module({
	imports: [ConfigModule],
	providers: [
		{
			provide: APP_FILTER,
			useClass: UnknownExceptionsFilter,
		},
		{
			provide: APP_GUARD,
			useClass: ConnnectionGuard,
		},
		AuthCommand,
	],
})
export class AppModule {}

The exception filter

import { Catch, ExceptionFilter } from '@nestjs/common';

@Catch()
export class UnknownExceptionsFilter implements ExceptionFilter {
	public catch() {
		console.log(5);
	}
}

Then I try to fail the program and throw an exception intentionally

import { Command, CommandRunner } from 'nest-commander';

@Command({ name: 'auth', description: 'Authenticate t' })
export class AuthCommand implements CommandRunner {
	public async run() {
		await Promise.resolve();

		throw new Error();
	}
}

But the exception handler does not do anything. Why?

[jmcdo29]

Enhancers (guards, pipes, interceptors, and filters) currently only work in contexts that have an idea of a "request". This is because it requires the NestApplication rather than a NestApplicationContext. To have this though, there is a requirement to include an HTTP adapter which is overkill for the context of CLI requests. For error handling, you can just add a try/catch around the command

[jmcdo29]

Like I said before, to make enhancers work, Nest needs an HTTP context (or some other external request like websocket or rpc). In the Standalone Context that nest-commander makes use of, enhancers don't work. This is how Nest is designed.

As I said before, I can work on making guards and filters usable, but I'll need to re-build some of Nest's code and I need to determine what will be expected in the ExecutionContext and ArgumentHost for the guards and filters.

[tal-rofe]

@jmcdo29

Regarding the injection of services that does not work for me,
when I try to inject a service into the command handler (@Command) nothing happens.

My main.ts file

import { CommandFactory } from 'nest-commander';

import { AppModule } from './app.module';

async function bootstrap() {
	await CommandFactory.run(AppModule);
}

bootstrap();

My app.module.ts file:

import { Module } from '@nestjs/common';

import { AuthCommand } from './commands/auth/Auth';
import { ConfigModule } from './modules/config/config.module';
import { ConnectionModule } from './modules/connection/connection.module';

@Module({
	imports: [ConfigModule, ConnectionModule],
	providers: [AuthCommand],
})
export class AppModule {}

My config.module.ts file:

import { Global, Module } from '@nestjs/common';
import { ConfigService } from './config.service';

@Global()
@Module({ providers: [ConfigService] })
export class ConfigModule {}

My config.service.ts file:

import { Injectable } from '@nestjs/common';
import { IConfig } from './config.interface';

@Injectable()
export class ConfigService {
	private _config: IConfig = {
		API_URL: 'blabla',
	};

	public getValue(key: keyof IConfig) {
		return this._config[key];
	}
}

Then, I try to inject the ConfigService within my command handler:

import { Command, CommandRunner } from 'nest-commander';

import { ConfigService } from '@/modules/config/config.service';
@Command({ name: 'auth', description: 'Authenticate dssfds CLI with an sdfdsf account' })
export class AuthCommand implements CommandRunner {
	constructor(private readonly configService: ConfigService) {}

	public async run() {
		const hasConnection = await this.configService.getValue('API_URL');

		console.log('blabla');
	}
}

When I run: node dist/main.js auth nothing happens. When I remove the injection:

```ts
import { Command, CommandRunner } from 'nest-commander';

import { ConfigService } from '@/modules/config/config.service';
@Command({ name: 'auth', description: 'Authenticate fddf CLI with an dfssdf account' })
export class AuthCommand implements CommandRunner {

	public async run() {

		console.log('blabla');
	}
}

Then if I run the same command again, I do see the message logged to the console.

[jmcdo29]

Your ConfigModule does not have the ConfigService exported. Nest is logging an error, but nest-commander sets logger: false to keep the command logs clean. You can set a logger yourself using the logger option just like you normally would with NestFactory.create and see that there's an injection error about not being able to find the ConfigService provider.

docs

[smolinari]

But why? Isn't it exactly the use for guard? I could build a guard for guarding commands with internet connectivity and apply it globally with Nestjs core features.

Why doesn't this implementation satisfy?

@tal-rofe - I'm still confused. If you are creating a command, you'd be calling an API, not expecting requests from it, only responses, right?

Scott

[tal-rofe]

@jmcdo29 Thanks, issue was resolved.

@smolinari

I think that a command handler is similar to controller handler. That's why I thought of apply guard and filters