Exception Filters

Nest에는 응용 프로그램에서 처리되지 않은 모든 예외를 처리 하는 기본 제공 예외 레이어.

cats.controller.ts

@Get()
async findAll() {
  throw new HttpException('Forbidden', HttpStatus.FORBIDDEN);
}

---

Custom exceptions

forbidden.exception.ts

export class ForbiddenException extends HttpException {
  constructor() {
    super('Forbidden', HttpStatus.FORBIDDEN);
  }
}

cats.controller.ts

@Get()
async findAll() {
  throw new ForbiddenException();
}

---

Built-in HTTP exceptions

• BadRequestException
• UnauthorizedException
• NotFoundException
• ForbiddenException
• NotAcceptableException
• RequestTimeoutException
• ConflictException
• GoneException
• PayloadTooLargeException
• UnsupportedMediaTypeException
• UnprocessableEntityException
• InternalServerErrorException
• NotImplementedException
• BadGatewayException
• ServiceUnavailableException
• GatewayTimeoutException

---

Exception filters

http-exception.filter.ts

import { ExceptionFilter, Catch, ArgumentsHost, HttpException } from '@nestjs/common';
import { Request, Response } from 'express';

@Catch(HttpException)
export class HttpExceptionFilter implements ExceptionFilter {
  catch(exception: HttpException, host: ArgumentsHost) {
    const ctx = host.switchToHttp();
    const response = ctx.getResponse<Response>();
    const request = ctx.getRequest<Request>();
    const status = exception.getStatus();

    response
      .status(status)
      .json({
        statusCode: status,
        timestamp: new Date().toISOString(),
        path: request.url,
      });
  }
}

---

Binding filters

cats.controller.ts

@Post()
@UseFilters(HttpExceptionFilter)
async create(@Body() createCatDto: CreateCatDto) {
  throw new ForbiddenException();
}

global filter

main.ts

async function bootstrap() {
  const app = await NestFactory.create(AppModule);
  app.useGlobalFilters(new HttpExceptionFilter());
  await app.listen(3000);
}
bootstrap();