Is there a way to cache in item forever ?

[EnricoMassone]

Hi,

this is a very simple question indeed.

I would like to know if there is a built in way to cache an item forever (the cached item never expires, so it is never removed from the cache).

Is there a way to specify a never expiring item when it is added to the cache or the only way to do so is setting a very long absolute expiration (something like DateTimeOffset.Now.AddYears(1)) ?

Thanks for helping

[DaveInCaz]

I think this is described in the API docs section "Custom cache policies", where it shows in part:

var options = new MemoryCacheEntryOptions(){ 
   Priority = CacheItemPriority.NotRemovable
};

Dave

[EnricoMassone]

I think this is described in the API docs section "Custom cache policies", where it shows in part:

var options = new MemoryCacheEntryOptions(){ 
   Priority = CacheItemPriority.NotRemovable
};

Dave

I agree with you.

To summarize, the trick to cache an item forever is calling one of the methods of IAppCache allowing you to pass an instance of MemoryCacheEntryOptions.

In order to cache the item forever you have to do two things on the MemoryCacheEntryOptions instance:

• do NOT set any property allowing you to control the expiration of the cache entry itself (properties like AbsoluteExpiration or SlidingExpiration). Just leave all of these properties to their default values.
• do set the property Priority to the value NeverRemove of the CacheItemPriority enumeration. This must be done in order to be sure that even if the Compact method is called, then the cache item won't be removed from the cache.

Please notice that the Compact method is meant to be called by the developer, based on what I know it is never called automatically by the internals of the ASP.NET core MemoryCache as you can verify from this issue (https://github.com/aspnet/AspNetCore.Docs/issues/11216). This is true regardless of whether the SizeLimit property has been set on the MemoryCache instance.