deep-jade•7mo ago

How to return a specific error message from the backend server for the resource update / create?

Hi, I'm using @nestjsx/crud adapter with Refine. What I want to do is that I want to rewrite some of the services and provide a meaningful error message when there's some validation errors on the backend, and show it on the front-end after saving the content. Is that doable?

11 Replies

kapa.ai•7mo ago

Hi @Eric Hu. I'm kapa.ai, your friendly support bot. I will try to answer your question by searching through the knowledge base. :wave: ---------------------- Yes, it's definitely doable. Refine supports server-side validation out-of-the-box in all useForm derivatives. To handle server-side validation, the data providers need to be correctly set up to return the errors in form submissions with a specific format. After this, Refine's useForm will propagate the errors to the respective form fields. Here's an example of how you can return a specific error message from the backend:

import { HttpError } from "@refinedev/core";  

const error: HttpError = {  
 message: "An error occurred while updating the record.",  
 statusCode: 400,  
 // the errors field is required for server-side validation.  
 // when the errors field is set, useForm will automatically display the error messages in the form with the corresponding fields.  
 errors: {  
 title: ["Title is required"],  
 content: {  
 key: "form.error.content",  
 message: "Content is required.",  
 },  
 tags: true,  
 },  
};

import { HttpError } from "@refinedev/core";  

const error: HttpError = {  
 message: "An error occurred while updating the record.",  
 statusCode: 400,  
 // the errors field is required for server-side validation.  
 // when the errors field is set, useForm will automatically display the error messages in the form with the corresponding fields.  
 errors: {  
 title: ["Title is required"],  
 content: {  
 key: "form.error.content",  
 message: "Content is required.",  
 },  
 tags: true,  
 },  
};

In this example, the errors field is required for server-side validation. When the errors field is set, useForm will automatically display the error messages in the form with the corresponding fields. The message field is the error message that you want to display. For more information, you can check out the Refine documentation on server-side validation (https://refine.dev/docs/guides-concepts/forms#server-side-validation-). ---------------------- Note: you can ask me a follow up question by @ mentioning me again :speech_balloon: ----------------------

kapa.ai•7mo ago

<@454649036289343500> kapa.ai is still learning and improving, please let us know how it did by reacting below

deep-jade•7mo ago

Thanks, I think it should work. However, how can I use it with @nestjsx/crud? I tried this but it doesn't work:

  async createOne(req: CrudRequest, dto: DeepPartial<QuestionTypeEntity>): Promise<QuestionTypeEntity> {
    return Promise.reject({
      message: 'This is an error from the server',
      statusCode: 403,
      errors: {
        name: 'Name should be at least 3 characters long',
      },
    })
    // return super.createOne(req, dto)
  }

  async createOne(req: CrudRequest, dto: DeepPartial<QuestionTypeEntity>): Promise<QuestionTypeEntity> {
    return Promise.reject({
      message: 'This is an error from the server',
      statusCode: 403,
      errors: {
        name: 'Name should be at least 3 characters long',
      },
    })
    // return super.createOne(req, dto)
  }

deep-jade•7mo ago

@kapa.ai How to use the code you showed me above? Should I install @refinedev/core on my backend?

kapa.ai•7mo ago

Let me check the knowledge base for you. One moment! :books: ---------------------- No, you don't need to install @refinedev/core on your backend. The code I provided was just an example of the structure that your backend should return when a validation error occurs. In your NestJS service, when a validation error occurs, you should throw an HttpException with a similar structure. Here's an example:

throw new HttpException({
  message: 'An error occurred while updating the record.',
  errors: {
    title: 'Title is required',
    content: 'Content is required',
  },
}, HttpStatus.BAD_REQUEST);

throw new HttpException({
  message: 'An error occurred while updating the record.',
  errors: {
    title: 'Title is required',
    content: 'Content is required',
  },
}, HttpStatus.BAD_REQUEST);

In this example, HttpException is a class from @nestjs/common and HttpStatus is an enum from the same package. The errors object keys should match the names of your form fields. The error messages you provide here will be displayed next to the corresponding form fields in the Refine form. Remember, the key point here is that your backend needs to return the errors in the mutation response with the expected format for Refine to handle them correctly. ---------------------- Note: you can ask me a follow up question by @ mentioning me again :speech_balloon: ----------------------

kapa.ai•7mo ago

<@454649036289343500> kapa.ai is still learning and improving, please let us know how it did by reacting below

deep-jade•7mo ago

@kapa.ai Is there any example with Nest.js? I tried this but it doesn't work:

  async createOne(req: CrudRequest, dto: DeepPartial<QuestionTypeEntity>): Promise<QuestionTypeEntity> {
    throw new HttpException(
      {
        message: 'An error occurred while updating the record.',
        errors: {
          name: 'Error!',
        },
      },
      HttpStatus.BAD_REQUEST
    )
  }

  async createOne(req: CrudRequest, dto: DeepPartial<QuestionTypeEntity>): Promise<QuestionTypeEntity> {
    throw new HttpException(
      {
        message: 'An error occurred while updating the record.',
        errors: {
          name: 'Error!',
        },
      },
      HttpStatus.BAD_REQUEST
    )
  }

kapa.ai•7mo ago

Let me check the knowledge base for you. One moment! :books: ---------------------- I'm sorry, but based on the information extracts provided, there isn't a specific example of handling server-side validation errors with Nest.js and Refine. However, the code you've shared seems correct in terms of throwing an HttpException with a specific error message. If it's not working as expected, the issue might be somewhere else in your code or it could be related to how the error is handled on the frontend with Refine. Refine expects errors to be in a specific format to handle them correctly. The errors object in the response should have keys that match the names of your form fields. The error messages you provide here will be displayed next to the corresponding form fields in the Refine form. If you're still having trouble, I would recommend checking the Refine documentation (https://refine.dev/docs) and Nest.js documentation (https://docs.nestjs.com/exception-filters) for more information on error handling. ---------------------- Note: you can ask me a follow up question by @ mentioning me again :speech_balloon: ----------------------

kapa.ai•7mo ago

<@454649036289343500> kapa.ai is still learning and improving, please let us know how it did by reacting below

deep-jade•7mo ago

It turned out that the adapter of @nestjsx/crud has got some issues with server error handling. I forked it and rewrote this part. And it works now.

rival-black•7mo ago

Hello @Eric Hu happy to see you fixed the issue, would you like to create a PR for this one?