Caching in custom code

The Kentico API allows developers to cache data in website code. To cache data, use the CacheHelper.Cache method.

This type of caching is applicable to any API result. The same caching API is also available in macros.

We recommend caching in code for any frequent API calls that load significant data from the Kentico database (or other external sources). For example, caching is typically a good idea when retrieving content in the code of MVC sites.

The following example shows the code behind of a custom user control that:

Loads user data from the Kentico database (with caching)
Displays the data using a BasicRepeater control




using System;
using System.Data;

using CMS.Helpers;
using CMS.Membership;

public partial class CachedUsers : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        // Ensures loading and caching of data
        // Uses CacheSettings that cache the data for 10 minutes under the cache key "customdatasource|..."
        // Automatically checks whether the given key is already in the cache
        DataSet data = CacheHelper.Cache(cs => LoadUsers(cs), new CacheSettings(10, "customdatasource|" + UserBasicRepeater.ClientID));

        // Assigns the data to the BasicRepeater control
        UserBasicRepeater.DataSource = data;
        UserBasicRepeater.DataBind();        
    }

    // Method that loads the required data
    // Called only if the data doesn't already exist in the cache
    private DataSet LoadUsers(CacheSettings cs)
    {
        // Loads all user accounts from the database
        DataSet result = UserInfoProvider.GetUsers();

        // Checks whether the data should be cached (based on the CacheSettings)
        if (cs.Cached)
        {
            // Sets a cache dependency for the data
            // The data is removed from the cache if the objects represented by the dummy key are modified (all user objects in this case)
            cs.CacheDependency = CacheHelper.GetCacheDependency("cms.user|all");
        }

        return result;
    }
}

The Cache method checks if the key specified by the CacheSettings object is in the cache:

If yes, the method directly loads the data from the cache.
If not, the code calls the custom private method (LoadUsers) with the CacheSettings as a parameter. The private method loads the data from the database, sets a cache dependency and saves the key into the cache for the specified number of minutes

You can use the caching API when handling data anywhere in your code.

Tip

If you do not need to access or set the CacheSettings in the method that loads the data, you can use a simplified version of the Cache method:




DataSet data = CacheHelper.Cache(LoadUsers, new CacheSettings(10, "customkey"));

private DataSet LoadUsers()
{
    ...
}

CacheSettings

When calling the Cache method, you need to specify a CMS.Helpers.CacheSettings object as a parameter. The settings configure the cache key that stores the data. If you set the same cache key name for multiple data loading operations, they share the same cached value.

You can work with the following properties of the CacheSettings:

CacheSettings property	Type	Description
CacheMinutes	int	The number of minutes for which the cache stores the loaded data. The default value is 10 minutes. We recommend using an interval of 1 to 60 minutes.
CacheDependency	CMSCacheDependency	Sets dependencies for the cache key (use the CacheHelper.GetCacheDependency method to get the dependency object). Make sure you always set cache dependencies, unless the CacheMinutes interval is set to an extremely short time or the cached content is predominantly static.
BoolCondition	bool	A boolean condition that must be fulfilled (true) in order to cache the loaded data.
Cached	bool	Indicates whether the data should be cached (based on the cache minutes and condition).
AllowProgressiveCaching	bool	Enables or disabled progressive caching, which ensures that multiple threads accessing the same data only load it once and reuse the result.