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Validate input parameters in NestJS Redis Microservice

What’s the right way to validate and transform parameters in Redis/TCP based NestJS microservice. I understand we can use pipelines and validators for API based microservices on HTTP. Should I be contended with manual validations? Are there examples for the same?

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  1. Chosen as BEST ANSWER
    0

    Here's the code that did the trick. Thanks to Jay McDoniel

    import { ArgumentsHost, Catch, ExceptionFilter, Logger } from "@nestjs/common";
import { RpcException } from '@nestjs/microservices';

@Catch(RpcException)
export class AWSImageOCRRequestFilter implements ExceptionFilter {
  private logger = new Logger('AWSImageOCRRequestFilter');

  catch(exception: RpcException, host: ArgumentsHost) {
    this.logger.log(exception.name, exception.message);
    return new RpcException(exception.getError());
  }
}

    Above filter goes into controller for it to kick-in when invoked

    @UseFilters(new AWSImageOCRRequestFilter())
  @MessagePattern('awsimageocr')
  async textractForImage(
    @Payload(new ValidationPipe({ whitelist: true }))
    scorecardReq: ScorecardRequest,
  )

    To support this filter, I have made my DTO validation like the code below

    export class ImageOCRRequest {
  @IsString()
  @IsNotEmpty()
  project: string;
  @IsString()
  @IsNotEmpty()
  file: string;
  @IsString()
  @IsNotEmpty()
  filename: string;
}

    If you miss any of the required parameters, you'll see an exception like below

    [Nest] 26692   - 03/23/2021, 5:11:20 PM   [RpcExceptionsHandler] Bad Request Exception +453863ms
Error: Bad Request Exception
    at ValidationPipe.exceptionFactory (/Users/XXXXXXX/Projects/Grange/Nest/nestimageservice/node_modules/@nestjs/common/pipes/validation.pipe.js:89:20)
    at ValidationPipe.transform (/Users/XXXXXXX/Projects/Grange/Nest/nestimageservice/node_modules/@nestjs/common/pipes/validation.pipe.js:65:30)
    at processTicksAndRejections (node:internal/process/task_queues:94:5)
    at async resolveParamValue (/Users/XXXXXXX/Projects/Grange/Nest/nestimageservice/node_modules/@nestjs/microservices/context/rpc-context-creator.js:106:31)
    at async Promise.all (index 0)
    at async pipesFn (/Users/XXXXXXX/Projects/Grange/Nest/nestimageservice/node_modules/@nestjs/microservices/context/rpc-context-creator.js:108:13)
    at async /Users/XXXXXXX/Projects/Grange/Nest/nestimageservice/node_modules/@nestjs/microservices/context/rpc-context-creator.js:43:17
    at async /Users/XXXXXXX/Projects/Grange/Nest/nestimageservice/node_modules/@nestjs/microservices/context/rpc-proxy.js:11:32
    at async ServerRedis.handleEvent (/Users/XXXXXXX/Projects/Grange/Nest/nestimageservice/node_modules/@nestjs/microservices/server/server.js:63:32)

  2. 0

    Pipes still work in microservices. You can create DTOs as you usually do for HTTP and bind the ValidatioinPipe in the same way.

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