BadRequestResponse

Namespace: RA.Utilities.Api.Results

The BadRequestResponse class is a specialized model for creating standardized 400 Bad Request responses, typically used to communicate validation failures to the client. It inherits from Response<T>, with the Result property typed as an array of BadRequestResult objects.

🎯 Purpose

The BadRequestResponse class is a specialized model designed to create standardized 400 Bad Request API responses, typically used for validation failures. It inherits from the base Response<T> class and streamlines the process of communicating input errors to the client.

Here's why it's so useful:

1. Standardizes Validation Errors: It provides a consistent structure for all validation-related errors. The Result property is specifically typed to hold an array of BadRequestResult objects, where each object details a single validation failure (e.g., which property failed, the error message, and the value that was attempted).

2. Reduces Boilerplate: It automatically sets the response properties for a bad request:

• ResponseCode: Set to 400 (from BaseResponseCode.BadRequest).
• ResponseType: Set to ResponseType.BadRequest.
• ResponseMessage: Defaults to "One or more validation errors occurred.".

3. Provides Clear Client Feedback: By returning a structured list of errors, you give the client precise, actionable feedback. A frontend application can easily parse this list and display the appropriate error message next to each invalid input field.

Using BadRequestResponse ensures that your API communicates validation problems clearly and consistently, which is essential for a good developer experience.

⚙️ How It Works

When you create an instance of BadRequestResponse, it pre-configures the following properties:

• ResponseCode: Set to 400 (from BaseResponseCode.BadRequest).
• ResponseType: Set to ResponseType.BadRequest.
• ResponseMessage: Defaults to "One or more validation errors occurred.".
• Result: Contains an array of BadRequestResult objects, each detailing a specific validation error.

🚀 Usage in a Controller

You can use this class in your controller actions when input validation fails. Create one or more BadRequestResult objects and pass them to the BadRequestResponse constructor.

using Microsoft.AspNetCore.Mvc;
using RA.Utilities.Api.Results;

[ApiController]
[Route("api/[controller]")]
public class UsersController : ControllerBase
{
    [HttpPost]
    public IActionResult CreateUser(CreateUserRequest request)
    {
        if (string.IsNullOrEmpty(request.Email))
        {
            // Create a validation error detail
            var validationError = new BadRequestResult(
                propertyName: "Email",
                errorMessage: "'Email' must not be empty.",
                attemptedValue: request.Email,
                errorCode: "NotEmptyValidator"
            );

            // Return a 400 Bad Request with the structured error
            return BadRequest(new BadRequestResponse(new[] { validationError }));
        }

        // ... proceed with user creation
        return Ok();
    }
}

Example JSON Output

The code above would produce the following JSON response body if the email was empty:

{
  "responseCode": 400,
  "responseType": "BadRequest",
  "responseMessage": "One or more validation errors occurred.",
  "result": [
    {
      "propertyName": "Email",
      "errorMessage": "'Email' must not be empty.",
      "attemptedValue": "",
      "errorCode": "NotEmptyValidator"
    }
  ]
}