How to give custom field name in laravel form validation error message

Title: Customizing Laravel Form Validation Error Messages for Specific Field Names Introduction: Laravel 8 is an amazing framework that offers a number of tools to create robust applications. One such tool is form validation, which ensures the data submitted by users meets certain criteria before being stored or processed. However, sometimes you may want more control over how error messages are displayed based on custom field names. This blog post will provide a detailed guide on how to achieve that in Laravel forms. 1. Understanding Form Request Validation Laravel provides form request validation to check the data sent through your application's frontend forms. It allows you to define the rules for each field and display helpful error messages when they are not met. 2. Accessing Custom Field Names in Error Messages To customize the names of fields displayed in error messages, you can use the 'attribute' attribute within your validation rule array. This will allow you to reference the actual form field name instead of a shortened version like 'cat'. 3. Implementation for Custom Form Request Class Let's assume we have a form with a text input named "Category" and an additional field with the name "Cat". You can create a new custom form request class that will handle these fields:

public function rules()
{
   return [
      'name' => 'required|min:3',
      'cat_field' => 'required',
   ];
}

Here, we have defined the validation rules for both fields. The form field 'name' has specific validation rules including 'required' and 'min:3' to ensure it is required and has a minimum length of three characters. As for 'cat_field', which corresponds to our customized 'Category' field name, its validation rule is simply 'required'. 4. Accessing Custom Field Names in Error Messages with Form Validation Exceptions Now that we have defined our validation rules, let's create a new exception class called 'CustomFormRequestException' and extend the default 'ValidationException' class. This will override the default message format generated by Laravel:

class CustomFormRequestException extends ValidationException {
   /**
    * Create a new validation exception with the given response.
    *
    * @param  array $errors
    */
   public function __construct(array $errors = [])
   {
      parent::__construct($errors);
   }

   /**
    * Get the error messages for the given field.
    *
    * @param  string $field
    * @return array
    */
   protected function getFieldErrors(string $field)
   {
      if (array_key_exists($field, $this->errors)) {
         return [$this->getLocalizedFieldName($field) => $this->errors[$field]];
      } else {
         foreach ($this->errors as $name => $messages) {
            if (in_array($field, $this->nestedFields($name))) {
               $subfields = array_keys(collect($messages)->toArray());
               if (count($subfields) && count($subelements = collect($messages)->pluck('0', true)) == 1) {
                  return [$field => $this->getFieldErrors($subelements[reset($subelements)]), $this->getFieldErrors(array_shift($subfields))];
               } else {
                  throw new \InvalidArgumentException('Cannot retrieve errors for field with nested errors.');
               }
            }
         }
      }

      return [];
   }
}

This 'CustomFormRequestException' class overrides the default exception message format and replaces it with a custom one. To achieve this, we need to modify the 'getFieldErrors' method to extract the field names based on our custom 'attribute' values. This will ensure that error messages are displayed using the desired names for each field. 5. Customizing Error Messages in Form Request Validation Exceptions Handler Now that we have our new exception class, we need to update the validation exceptions handler. In your project, open the 'app/Exceptions/HandleValidationErrors.php' file and create a method called 'renderCustomValidationException'. This will replace the default handling code with one that uses the 'CustomFormRequestException' for displaying custom error messages:

/**
* Render a validation exception into a JSON response.
*
* @param  \Illuminate\Http\Request  $request
* @param  Validator  $validator
* @return \Symfony\Component\HttpKernel\Exception\HttpException|null
*/
protected function renderCustomValidationException($request, $validator)
{
   if ($exception = parent::render($request, $validator)) {
      $errors = $exception->getErrors();
      foreach ($errors as &$errorMessages) {
         foreach ($errorMessages as $key => $value) {
            $attributeName = array_search($this->resolveAttribute($request, $key), $validator->customAttributes());
            if (is_numeric($attributeName)) {
               $errorMessages[$key] = [$this->getLocalizedFieldName((string) $attributeName) => $value];
            }
         }
      }
      return new CustomFormRequestException($errors);
   }

   return null;
}

In this method, we access the original error messages and modify them to include the customized field names extracted from the 'attribute' values. Finally, we create a new 'CustomFormRequestException' instance with these modified errors before returning it. 6. Conclusion This comprehensive guide has demonstrated how you can customize the validation error messages in Laravel forms. By creating a custom form request class with appropriate validation rules and using an exception handler that displays field names based on our custom 'attribute' values, we now have full control over how errors are displayed to users. This will improve the overall user experience by providing more understandable and clearer error messages. Keep in mind, you can always refer back to https://laravelcompany.com for further assistance or resources related to Laravel development.