how we implement dto validation in nestjs TCP microservice

Question

I need to implement dto validation in nestjs micro-service

a complete implementation of dto in nestjs TCP micro-service**strong text**

checkRemitter.dto.ts
```typescript
    import { IsNotEmpty, IsString } from 'class-validator';


export class checkRemitterDto {
  @IsNotEmpty()
  @IsString()
  readonly remitterNo: string;

  @IsNotEmpty()
  @IsString()
  userId: string
}
```



app. controller

```typescript
    import {checkRemitterDto} from "./dto"
  @MessagePattern({ cmd: "checkRemitter" })
  async checkRemitterData(data: checkRemitterDto) {
    try{
       //some code
    }catch(error){
      console.log(error)
      return new HttpException(error.response.data, error.response.status);
    }
  }

```
error=>


BadRequestException: Bad Request Exception
    at ValidationPipe.exceptionFactory (/home/saranjith/Desktop/ECAPS/yesbank-dmtsor-service/node_modules/@nestjs/common/pipes/validation.pipe.js:90:20)
    at ValidationPipe.transform (/home/saranjith/Desktop/ECAPS/yesbank-dmtsor-service/node_modules/@nestjs/common/pipes/validation.pipe.js:66:30)
    at processTicksAndRejections (node:internal/process/task_queues:95:5)
    at resolveParamValue (/home/saranjith/Desktop/ECAPS/yesbank-dmtsor-service/node_modules/@nestjs/microservices/context/rpc-context-creator.js:106:31)
    at async Promise.all (index 0)
    at pipesFn (/home/saranjith/Desktop/ECAPS/yesbank-dmtsor-service/node_modules/@nestjs/microservices/context/rpc-context-creator.js:108:13)
    at /home/saranjith/Desktop/ECAPS/yesbank-dmtsor-service/node_modules/@nestjs/microservices/context/rpc-context-creator.js:43:17
    at /home/saranjith/Desktop/ECAPS/yesbank-dmtsor-service/node_modules/@nestjs/microservices/context/rpc-proxy.js:11:32
    at ServerTCP.handleMessage (/home/saranjith/Desktop/ECAPS/yesbank-dmtsor-`enter code here`service/node_modules/@nestjs/microservices/server/server-tcp.js:62:54)`enter code here`

Answer 1

Microservices use RpcException class. You can change ValidationPipe exception factory in main.ts And you should throw RpcException instead of http expception

main.ts

 async function bootstrap() {
  const microserviceApp = await NestFactory.createMicroservice<MicroserviceOptions>(AppModule, {
     transport: Transport.REDIS,
     // ...
   });

  // ...
  microServiceApp.useGlobalPipes(new ValidationPipe({
      transform: true,
      whitelist: true,
      forbidNonWhitelisted: true,
      forbidUnknownValues: true,
      disableErrorMessages: true,
      exceptionFactory: (errors) => {
         return new RpcException(errors);
      }
  }));
  // ...
}