ASP.NET Core Sessions Usage

NCache provides integration with ASP.NET Core Sessions through the implementation of the common IDistributedCache interface. Using NCache as a Distributed Session Store becomes possible without any change in the existing code. Storing the session state in a distributed NCache cluster ensures that sessions are persisted, scalable, and highly available in a web farm.

For more detail on IDistributedCache methods, have a look at their documentation.

Using ASP.NET Core Sessions For a Single Cache

The following code sample looks for the cache key in the cache, if it is found, it returns the view with the result. If not, it adds the cache key against its corresponding cache entry and sets the Sliding Expiration of the cache entry to 30 minutes.

To use ASP.NET Core Sessions, update HomeController.cs of your application:

// Constructor injection for the IDistributedCache interface

public class HomeController : Controller
{
    private IDistributedCache _cache;

    public HomeController(IDistributedCache Cache)
    {
        // NCache is the underlying distributed provider
        _cache = Cache;
    }

    public IActionResult CacheOperations()
    {
        // Cache entry is of DateTime type
        DateTime cacheEntry;

        string cacheKey = "MaxValue: " + DateTime.MaxValue;

        // Look for cache key
        object retrieveObj = _cache.Get(cacheKey);

        // Check if key exists in cache
        if (retrieveObj != null)
        {
            // Return view with result
        }
        else
        {
            // Key not in cache, so populate data in cache entry
            cacheEntry = DateTime.MaxValue;



           // Define sliding expiration to keep sessions alive based on activity
            var cacheEntryOptions = new DistributedCacheEntryOptions();
            cacheEntryOptions.SlidingExpiration = TimeSpan.FromMinutes(30);

            // Insert item in cache
            _cache.Set(cacheKey, new byte[1024], cacheEntryOptions);

            // Return view with cacheEntry
        }
    }
}

Using ASP.NET Core Sessions For Multiple Caches

To utilize multiple caches with ASP.NET Core Sessions, modify your HomeController.cs to use the IDistributedCacheFactory, enabling dynamic cache selection for session management based on specific cache configurations.

public class HomeController : Controller
{
    private IDistributedCacheFactory _cache;

    public HomeController(IDistributedCacheFactory cacheFactory)
    {
        // Underlying cache is NCache
        _cache = cacheFactory.GetDistributedCache("demoClusteredCache");
    }

    public IActionResult CacheOperations()
    {
        // Cache entry is of DateTime type
        DateTime cacheEntry;

        string cacheKey = "MaxValue: " + DateTime.MaxValue;

        // Look for cache key
        object retrieveObj = _cache.Get(cacheKey);

        // Check if key exists in cache
        if (retrieveObj != null)
        {
            // Return view with result
        }
        else
        {
            // Key not in cache, so populate data in cache entry
            cacheEntry = DateTime.MaxValue;

            // Configure SlidingExpiration for item
            var cacheEntryOptions = new DistributedCacheEntryOptions();
            cacheEntryOptions.SlidingExpiration = TimeSpan.FromMinutes(30);

            // Insert item in cache
            _cache.Set(cacheKey, new byte[1024], cacheEntryOptions);

            // Return view with cacheEntry
        }
    }
}

Additional Resources

NCache provides sample application for Session Caching on GitHub.

See Also

.NET: Alachisoft.NCache.Caching.Distributed namespace.