public async Task <IActionResult> GetProductSpecificationAttributeById(int id, string fields = "") { if (id <= 0) { return(Error(HttpStatusCode.BadRequest, "id", "invalid id")); } var productSpecificationAttribute = await _specificationAttributeService.GetProductSpecificationAttributeByIdAsync(id); if (productSpecificationAttribute == null) { return(Error(HttpStatusCode.NotFound, "product specification attribute", "not found")); } var productSpecificationAttributeDto = _dtoHelper.PrepareProductSpecificationAttributeDto(productSpecificationAttribute); var productSpecificationAttributesRootObject = new ProductSpecificationAttributesRootObjectDto(); productSpecificationAttributesRootObject.ProductSpecificationAttributes.Add(productSpecificationAttributeDto); var json = JsonFieldsSerializer.Serialize(productSpecificationAttributesRootObject, fields); return(new RawJsonActionResult(json)); }