using System;

using Microsoft.Extensions.Caching.Memory;

using Microsoft.Extensions.Options;

​

public class Program

{

    public static void Main()

    {

        UsingExample();

        CacheExample();

    }

    static void UsingExample()

    {

        Console.WriteLine(">> Using Example\n");

​

        IMemoryCache cache = new MemoryCache(Options.Create<MemoryCacheOptions>(new MemoryCacheOptions()));

        // happens inside of MemoryCache.GetOrCreate()

        using (var parent = cache.CreateEntry("parent"))

        {

            parent.Value = "parent value";

            parent.AbsoluteExpiration = DateTime.Now.AddHours(4);

​

            // happens inside of MemoryCache.Set()

            using (var child = cache.CreateEntry("child"))

            {

                child.Value = "child value";

                child.AbsoluteExpiration = DateTime.Now.AddMinutes(1);

​

                parent.AbsoluteExpiration.Dump("parent expiration before child dispose");

                child.AbsoluteExpiration.Dump("child expiration");

            }

​

            parent.AbsoluteExpiration.Dump("parent expiration after child dispose");

        }

    }

​

    static void CacheExample()

    {

        Console.WriteLine(">> Cache Example\n");

​

        IMemoryCache cache = new MemoryCache(Options.Create<MemoryCacheOptions>(new MemoryCacheOptions()));

        OuterCache(cache);

    }

​

    static string OuterCache(IMemoryCache cache)

    {    

        return cache.GetOrCreate("outer", c => {

            c.AbsoluteExpiration = DateTime.Now.AddHours(4);

            c.AbsoluteExpiration.Dump("GetOrCreate expiration before inner");

​

            string result = InnerCache(cache, c);

            c.AbsoluteExpiration.Dump("GetOrCreate expiration after inner");

            return result;

        });

    }

​

    static string InnerCache(IMemoryCache cache, ICacheEntry e)

    {

        if (cache.TryGetValue<string>("inner", out var s))

            return s;

​

        return cache.Set("inner", "foo", DateTime.Now.AddSeconds(1));

    }

}

​

public static class E

{

    public static void Dump(this object o, string d)

    {

        Console.WriteLine("// " + d);

        Console.WriteLine(o.ToString());

        Console.WriteLine();

    }

}