Usermanager/Http/Requests/Role/UpdateRoleRequest.php

<?php

    namespace Modules\Usermanager\Http\Requests\Role;

    use Illuminate\Foundation\Http\FormRequest;
    use Illuminate\Http\Exceptions\HttpResponseException;
    use Illuminate\Http\JsonResponse;
    use Illuminate\Validation\ValidationException;
    use Illuminate\Validation\Validator;

    class UpdateRoleRequest extends FormRequest
    {
        /**
         * Determine if the user is authorized to make this request.
         */
        public function authorize()
        : bool
        {
            return true;
        }

        /**
         * Get the validation rules that apply to the request.
         *
         * @return array<string, \Illuminate\Contracts\Validation\Rule|array|string>
         */
        public function rules()
        : array
        {
            return [
                'name'       => 'required|max:100|unique:roles,name,' . $this->role->id,
                'guard_name' => 'nullable|max:100|string'
            ];
        }

        /**
         * Configure the validator instance.
         */
        public function withValidator(Validator $validator)
        : void
        {
            $validator->after(function (Validator $validator) {
                if ($validator->errors()->any()) {
                    $error = json_decode($validator->errors()->toJson(), true);
                    foreach ($error as $key => $value) {
                        flash($value[0]);
                    }

                    return redirect()->route('user.roles.index')->with('error', 'Role updated failed.');
                }
            });
        }

        protected function failedValidation(Validator|\Illuminate\Contracts\Validation\Validator $validator)
        : JsonResponse
        {
            $errors = (new ValidationException($validator))->errors();

            throw new HttpResponseException(response()->json([
                'success'  => false,
                'errors'   => $errors,
                'messages' => 'Role updated failed.'
            ], JsonResponse::HTTP_UNPROCESSABLE_ENTITY));
        }
    }