NestJS - WebsocketGateway 中的 ValidationPipe 返回内部服务器错误

Posted 2023-03-10

【中文标题】NestJS - WebsocketGateway 中的 ValidationPipe 返回内部服务器错误

【英文标题】：NestJS - ValidationPipe in WebsocketGateway returns Internal Server Error

【发布时间】：2020-06-30 02:43:16

【问题描述】：

我正在尝试在 NestJS 中向我的 WebSocketGateway 添加一些验证。代码如下：

// MessageDTO

import  IsNotEmpty, MinLength  from 'class-validator';

export class MessageDTO 
  @IsNotEmpty()
  username: string;

  @IsNotEmpty()
  @MinLength(10)
  text: string;

// Gateway

import  ValidationPipe, UsePipes  from '@nestjs/common';
import  MessageBody, SubscribeMessage, WebSocketGateway, WsResponse  from '@nestjs/websockets';
import  MessageService  from './message/message.service';
import  MessageDTO  from './message/message.dto';
import  Message  from './message/message.entity';

@WebSocketGateway()
export class AppGateway 
  constructor(private readonly messageService: MessageService) 

  @UsePipes(new ValidationPipe())
  @SubscribeMessage('message')
  async handleMessage(@MessageBody() dto: MessageDTO): Promise<WsResponse<Message>> 
    const message = await this.messageService.saveMessage(dto);
    return  event: 'message', data: message ;
  

现在，当我尝试发送不符合验证规则的消息时，它会出错，但客户端始终会收到 status: 'error', message: 'Internal server error'。此外，Nest 将错误记录到控制台（我认为这不应该发生......？）：

thing_api | Error: Bad Request Exception
thing_api |     at ValidationPipe.exceptionFactory (/usr/src/app/node_modules/@nestjs/common/pipes/validation.pipe.js:78:20)
thing_api |     at ValidationPipe.transform (/usr/src/app/node_modules/@nestjs/common/pipes/validation.pipe.js:50:24)
thing_api |     at processTicksAndRejections (internal/process/task_queues.js:89:5)
thing_api |     at async resolveParamValue (/usr/src/app/node_modules/@nestjs/websockets/context/ws-context-creator.js:104:31)
thing_api |     at async Promise.all (index 0)
thing_api |     at async pipesFn (/usr/src/app/node_modules/@nestjs/websockets/context/ws-context-creator.js:106:13)
thing_api |     at async /usr/src/app/node_modules/@nestjs/websockets/context/ws-context-creator.js:41:17
thing_api |     at async AppGateway.<anonymous> (/usr/src/app/node_modules/@nestjs/websockets/context/ws-proxy.js:11:32)
thing_api |     at async WebSocketsController.pickResult (/usr/src/app/node_modules/@nestjs/websockets/web-sockets-controller.js:85:24)

但是，如果我在常规控制器中使用相同的 DTO 和验证管道，它就像一个魅力 - 使用格式错误的有效负载我会收到格式正确的错误消息。有人能指出我做错了什么吗？

【问题讨论】：

您找到解决问题的方法了吗？我也一样

【参考方案1】：

BadRequestException 是HttpException 的子类。 Nest 的默认 exception handler for websockets 检查捕获的异常是否为 instanceof WsException，如果不是则返回未知异常。

要解决这个问题，您可以实现一个过滤器，捕获 BadRequestException 并将其转换为适当的 WsException，然后让 Nest 的异常过滤器从那里处理异常。

@Catch(BadRequestException)
export class BadRequestTransformationFilter extends BaseWsExceptionFilter 
  catch(exception: BadRequestException, host: ArgumentHost) 
    const properException = new WsException(exception.getResponse());
    super.catch(properException, host);
  

【参考方案2】：

我已经创建了我的 SocketValidation 管道

import  PipeTransform, Injectable, ArgumentMetadata, ValidationPipe  from '@nestjs/common';
import  validate  from 'class-validator';
import  plainToClass  from 'class-transformer';
import  WsException  from '@nestjs/websockets';

@Injectable()
export class SocketValidationPipe  implements PipeTransform<any> 

  constructor() 
    // super(options)
  

  async transform(value: any,  metatype : ArgumentMetadata) 
    if (!metatype || !this.toValidate(metatype)) 
      return value;
    
    const object = plainToClass(metatype, JSON.parse(value));
    const errors = await validate(object);
    if (errors.length > 0) 
      throw new WsException('Wrong message!');//new BadRequestException('Validation failed');
    
    return value;
  

  private toValidate(metatype: Function): boolean 
    const types: Function[] = [String, Boolean, Number, Array, Object];
    return !types.includes(metatype);
  

【讨论】：

请解释一下这段代码是如何解决这个问题的？

【参考方案3】：

你可以重写the default websocket filter，捕获http异常和websocket异常。

import  ArgumentsHost, Catch, HttpException  from '@nestjs/common';
import  WsException  from '@nestjs/websockets';
import  Socket  from 'socket.io';

@Catch(WsException, HttpException)
export class WsExceptionFilter 
  public catch(exception: HttpException, host: ArgumentsHost) 
    const client = host.switchToWs().getClient();
    this.handleError(client, exception);
  

  public handleError(client: Socket, exception: HttpException | WsException) 
    if (exception instanceof HttpException) 
      // handle http exception
     else 
      // handle websocket exception
    
  

然后在你的网关中使用它

@UseFilters(WsExceptionFilter)
@WebSocketGateway()
export class WorkspacesGateway 

【参考方案4】：

ValidationPipe 获得了exceptionFactory 选项，因此您可以将自定义工厂传递给它，例如：

@UsePipes(new ValidationPipe(
    exceptionFactory(validationErrors = []) 
        if (this.isDetailedOutputDisabled) 
            return new WsException('Bad request');
        
        const errors = this.flattenValidationErrors(validationErrors);

        return new WsException(errors);
    
))

或者扩展内置的ValidationPipe

import Injectable, ValidationPipe from '@nestjs/common';
import WsException from "@nestjs/websockets";

@Injectable()
export class WSValidationPipe extends ValidationPipe

  createExceptionFactory() 
    return (validationErrors = []) => 
      if (this.isDetailedOutputDisabled) 
        return new WsException('Bad request');
      
      const errors = this.flattenValidationErrors(validationErrors);

      return new WsException(errors);
    ;