Exception filterlar

HTTP exception filter qatlamidan microservices qatlamiga yagona farq shundaki, HttpException tashlash o'rniga RpcExceptiondan foydalanishingiz kerak.

1throw new RpcException('Invalid credentials.');

Yuqoridagi namunada Nest tashlangan exceptionni qayta ishlaydi va quyidagi struktura bilan error obyektini qaytaradi:

1{
2  "status": "error",
3  "message": "Invalid credentials."
4}

Filterlar

Microservice exception filterlari HTTP exception filterlariga o'xshash ishlaydi, bitta kichik farq bilan. catch() metodi Observable qaytarishi kerak.

1import { Catch, RpcExceptionFilter, ArgumentsHost } from '@nestjs/common';
2import { Observable, throwError } from 'rxjs';
3import { RpcException } from '@nestjs/microservices';
4
5@Catch(RpcException)
6export class ExceptionFilter implements RpcExceptionFilter<RpcException> {
7  catch(exception: RpcException, host: ArgumentsHost): Observable<any> {
8    return throwError(() => exception.getError());
9  }
10}

Quyidagi misolda qo'lda instansiyalangan method-scoped filter ishlatiladi. HTTP asosidagi ilovalar kabi, controller-scoped filterlardan ham foydalanishingiz mumkin (ya'ni, controller klassiga @UseFilters() dekoratorini qo'shing).

1@UseFilters(new ExceptionFilter())
2@MessagePattern({ cmd: 'sum' })
3accumulate(data: number[]): number {
4  return (data || []).reduce((a, b) => a + b);
5}

Meros olish

Odatda, ilovangiz talablariga moslashtirilgan to'liq custom exception filterlar yaratasiz. Biroq, ayrim hollarda shunchaki core exception filterni kengaytirib, ayrim omillarga qarab xatti-harakatni override qilishni xohlashingiz mumkin.

Exceptionni bazaviy filterga delegatsiya qilish uchun BaseExceptionFilterni kengaytirib, meros bo'lib kelgan catch() metodini chaqirishingiz kerak.

1import { Catch, ArgumentsHost } from '@nestjs/common';
2import { BaseRpcExceptionFilter } from '@nestjs/microservices';
3
4@Catch()
5export class AllExceptionsFilter extends BaseRpcExceptionFilter {
6  catch(exception: any, host: ArgumentsHost) {
7    return super.catch(exception, host);
8  }
9}

Yuqoridagi implementatsiya yondashuvni ko'rsatadigan soddalashtirilgan skelet xolos. Kengaytirilgan exception filteringiz implementatsiyasida sizning moslashtirilgan biznes mantiqingiz (masalan, turli shartlarni qayta ishlash) bo'ladi.