How do I clear the HTML cache for a specific user?

Question

We have an action that updates some user profile information that is displayed in components that are cached with a vary by user setting. Is there a way to clear the cache for only that one user?

Answer 1

You can do this by making sure that your renderings are set to Vary by User. This adds the user to the cacheKey string like this "_#user:" + Context.GetUserName();

You can then use the following code to clear the html cache for that user:

// Need to clear the cache for the header and the user profile....
var htmlCache = CacheManager.GetHtmlCache(Context.Site);

// Remove all cache keys that contain the currently logged in user.
var cacheKeyPart = $"_#login:True_#user:{Context.GetUserName()}";
htmlCache.RemoveKeysContaining(cacheKeyPart);

For more detailed information have a look at this post: http://www.sitecorenutsbolts.net/2016/04/26/Advanced-Cache-Clearing/

Answer 2

This depends on how often does the data change and what triggers the change.

One possible option would be to use additionally vary by query string option which will cache the output for the user and specific value of query string. This way every time the user changes their query (thus changing query string) the ouput will be rendered from scratch.

On the other hand if the data changes often it might be worth considerig turning off the cache at all(for this particular rendering).