redis-blog-post-2.cs

var cacheKey = string.Format(ApplicationServices.Constants.DistributedCache.CacheKeyFormats.CategoryById, id);
CategoryDto? categoryDto = await _distributedCache.GetAsync<CategoryDto>(cacheKey);
if (categoryDto is not null)
{
    return categoryDto;
}

categoryDto = await _categoryService.GetCategoryById(id);
if (categoryDto is null)
{
    return NotFound();
}

await _distributedCache.SetAsync(cacheKey, categoryDto);

return Ok(categoryDto);