Hi all.

We are caching redirect urls and are trying to convert our code from Umbraco 8 to Umbraco 9 and are missing the good old CacheItemRemovedCallback from System.Web.Caching.

In Umbraco 8 we used Umbraco.Core.Cache.AppCacheExtensions:

public static void InsertCacheItem<T>(this IAppPolicyCache provider, string cacheKey, Func<T> getCacheItem, TimeSpan? timeout = null, bool isSliding = false, CacheItemPriority priority = CacheItemPriority.Normal, CacheItemRemovedCallback removedCallback = null, string[] dependentFiles = null);

Like this:

protected void InsertIntoCache(object item)
{
    appCaches.RuntimeCache.InsertCacheItem("customKey", () => item, null, false, CacheItemPriority.Normal, new CacheItemRemovedCallback(CachedItemRemovedCallback), new string[] { "D:\\root\\web\\app_data\\somefile.txt" });
}

protected void CachedItemRemovedCallback(string key, object val, CacheItemRemovedReason reason)
{       
    if (key.Contains(Key))
    {
        var item = Get(); // Some function to get item for Cache.
        InsertIntoCache(item);
    }
}

In Umbraco 9 there is no CachedItemRemovedCallback in Umbraco.Extensions.AppCacheExtensions:

public static void InsertCacheItem<T>(this IAppPolicyCache provider, string cacheKey, Func<T> getCacheItem, TimeSpan? timeout = null, bool isSliding = false, string[] dependentFiles = null)

So how do we setup something similar in Umbraco 9?