如果 NestJS 异常过滤器来自 ValidationPipe，则会弄乱错误数组

Question

所以我使用 ValidationPipe 在 NestJS 中验证我的 DTO，如下所示：

// auth.dto.ts
export class AuthDto {
  @IsEmail()
  @IsNotEmpty()
  email: string;
}

如果没有异常过滤器，错误消息将按预期工作。我将电子邮件字段留空并收到一系列错误消息：

// Response - Message array, but no wrapper
{
  "statusCode": 400,
  "message": [
    "email should not be empty",
    "email must be an email"
  ],
  "error": "Bad Request"
}

完美。现在我想为错误消息实现一个包装器，所以我创建了一个新过滤器并将其添加到 bootstrap:

// main.ts
async function bootstrap() {
  // ...
  app.useGlobalFilters(new GlobalExceptionFilter());
}
bootstrap();

// global-exception.filter.ts
import {
  ArgumentsHost,
  Catch,
  ExceptionFilter,
  HttpException,
  HttpStatus,
} from '@nestjs/common';
import { Response } from 'express';
import { IncomingMessage } from 'http';

export const getStatusCode = <T>(exception: T): number => {
  return exception instanceof HttpException
    ? exception.getStatus()
    : HttpStatus.INTERNAL_SERVER_ERROR;
};

export const getErrorMessage = <T>(exception: T): string => {
  return exception instanceof HttpException
    ? exception.message
    : String(exception);
};

@Catch()
export class GlobalExceptionFilter<T> implements ExceptionFilter {
  catch(exception: T, host: ArgumentsHost) {
    const ctx = host.switchToHttp();
    const response = ctx.getResponse<Response>();
    const request = ctx.getRequest<IncomingMessage>();
    const statusCode = getStatusCode<T>(exception);
    const message = getErrorMessage<T>(exception);

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

它对我的大部分错误都很有效：

// Response - Good format (wrapped), single message expected
{
  "error": {
    "timestamp": "2022-05-11T19:54:59.093Z",
    "path": "/auth/signup",
    "statusCode": 400,
    "message": "Email already in use"
  }
}

但是当我从 ValidationPipe 收到 ValidationError 时，它应该像以前一样给我一个数组或消息，但它却给出了这条消息：

// Response - Wrapper: check, single message instead of array
{
  "error": {
    "timestamp": "2022-05-11T19:59:17.282Z",
    "path": "/auth/signup",
    "statusCode": 400,
    "message": "Bad Request Exception" // it should be "message": ["not empty", "must be email"]
  }
}

我的异常过滤器中的异常对象有一个包含消息数组的响应字段：

// HttpException object inside the filter class
{
  response: {
    statusCode: 400,
    message: [ 'email should not be empty', 'email must be an email' ],
    error: 'Bad Request'
  },
  status: 400
}

但是exception.response.message不起作用，因为该字段是私有的并且TypeScript会抛出错误：
Property 'response' is private and only accessible within class 'HttpException'.

你们有谁知道我怎样才能到达消息数组，这样我才能正确地格式化我的错误响应？

编辑：很抱歉 post！

Answer 1

正如 @tobias-s 评论的那样，有一个解决方法解决了问题：

Try exception["response"]["message"]. This bypasses the private restriction

如果 NestJS 异常过滤器来自 ValidationPipe，则会弄乱错误数组

NestJS Exception filter messes up error array if it comes from ValidationPipe

httpexception

node.js

typescript

nestjs