Exception Filters

The websockets exceptions layer works exact same as the prime layer. The only difference is that instead of throwing HttpException, you should throw RpcException.

throw new RpcException('Invalid credentials.');

Notice The RpcException class is imported from the @nestjs/microservices package.

Nest would handle this exception and emits the exception message with the following data:

{
  status: 'error',
  message: 'Invalid credentials.'
}

Exception Filters

The Exception Filters are also really similar, and works exactly in the same way as the primary ones. The only difference is that catch() method should returns an Observable.

import { Catch, RpcExceptionFilter } from '@nestjs/common';
import { Observable } from 'rxjs/Observable';
import { RpcException } from '@nestjs/microservices';
import 'rxjs/add/observable/throw';

@Catch(RpcException)
export class ExceptionFilter implements RpcExceptionFilter {
  catch(exception: RpcException): Observable<any> {
    return Observable.throw(exception.getError());
  }
}

import { Catch } from '@nestjs/common';
import { Observable } from 'rxjs/Observable';
import { RpcException } from '@nestjs/microservices';
import 'rxjs/add/observable/throw';

@Catch(RpcException)
export class ExceptionFilter {
  catch(exception) {
    return Observable.throw(exception.getError());
  }
}

Notice It's impossible to set up the microservices exception filters globally.