How are AbsoluteExpiration, AbsoluteExpirationRelativeToNow and SlidingExpiration used on DistributedCacheEntryOptions?

Question

I'm in charge of implementing a session state server with ASP.NET Core gRPC, and its corresponding client, to have session state management for a load-balanced group of ASP.NET Core applications. That means the client must implement IDistributedCache for that.

The methods Set and SetAsync have a parameter of type DistributedCacheEntryOptions and this class has the properties AbsoluteExpiration, AbsoluteExpirationRelativeToNow and SlidingExpiration. I presume these properties can be used to signal when a cache entry has expired, but how are they used and how am I to interpret them? Seeing that the 3 properties are nullables, is it that only one of the three is to be populated?

Answer 1

So, as far as I can tell, you're supposed to use only one of those properties (the one that matches your use case). In my case, all I had to do is to use SlidingExpiration and that covered my use case. Other contexts might require other strategies.