Caching in .NET6+ Using IMemoryCache - Console Example

CacheHelper.cs

using Microsoft.Extensions.Caching.Memory;
using Microsoft.Extensions.Primitives;
using System;


namespace CacheTest
{
    public class CacheHelper
    {
        private IMemoryCache _memoryCache { get; } = new MemoryCache(
        new MemoryCacheOptions
        {
            SizeLimit = 1024, /* CHECK THIS IS THIS THE RIGHT SIZE FOR YOU! */
            CompactionPercentage = .3,
            ExpirationScanFrequency = TimeSpan.FromSeconds(30),
        });


        public bool AddToCache(string key, int expriryTimeInSeconds)
        {
            bool isSuccess = false;

            if (!IsInCache(key))
            {
                var currntCount = ((MemoryCache)_memoryCache).Count;
                Console.WriteLine("Cache Size: " + currntCount);
       
                var cancellationTokenSource = new CancellationTokenSource(
                                                     TimeSpan.FromSeconds(3));

                var cacheEntryOptions = new MemoryCacheEntryOptions()
                    .SetSize(1)
                    .AddExpirationToken(
                        new CancellationChangeToken(cancellationTokenSource.Token));

                _memoryCache.Set(key, DateTime.Now, cacheEntryOptions);

                var currntCount2 = ((MemoryCache)_memoryCache).Count;
                Console.WriteLine("New Cache Size: " + currntCount2);

                isSuccess = true;
            }

            return isSuccess;
        }


        public bool AddToCache<T>(string key, T value, int expriryTimeInSeconds)
        {
            bool isSuccess = false;

            if (!IsInCache(key))
            {
                var currntCount = ((MemoryCache)_memoryCache).Count;
                Console.WriteLine("Cache Size: " + currntCount);

                var cancellationTokenSource = new CancellationTokenSource(
                                                     TimeSpan.FromSeconds(expriryTimeInSeconds));

                var cacheEntryOptions = new MemoryCacheEntryOptions()
                    .SetAbsoluteExpiration(DateTimeOffset.Now.AddSeconds(expriryTimeInSeconds))
                    .SetSize(1)
                    .AddExpirationToken(
                        new CancellationChangeToken(cancellationTokenSource.Token));

                _memoryCache.Set<T>(key, value, cacheEntryOptions);

                var currntCount2 = ((MemoryCache)_memoryCache).Count;
                Console.WriteLine("New Cache Size: " + currntCount2);

                isSuccess = true;
            }

            return isSuccess;
        }

        public T GetFromCache<T>(string key)
        {
            return _memoryCache.Get<T>(key);
        }


        public bool IsInCache(string key)
        {
            var item = _memoryCache.Get(key);

            return item != null;
        }


    }
}

Program.cs

// See https://aka.ms/new-console-template for more information
Console.WriteLine("Hello, World!");


CacheTest.CacheHelper cache = new CacheTest.CacheHelper();

var seconds = 3;
var key1 = "Test1";


Console.WriteLine("Should pass ");
if (cache.AddToCache(key1, seconds))
{
    Console.WriteLine($"pass {key1}");
}
else
{
    Console.WriteLine($"fail {key1}");
}


var key2 = "Test2";

Console.WriteLine("Should pass ");
if (cache.AddToCache(key2, seconds))
{
    Console.WriteLine($"pass {key2}");
}
else
{
    Console.WriteLine($"fail {key2}");
}

await Task.Delay(1000);
Console.WriteLine();

Console.WriteLine("Should fail ");
if (cache.AddToCache(key1, seconds))
{
    Console.WriteLine($"pass {key1}");
}
else
{
    Console.WriteLine($"fail {key1}");
}

Console.WriteLine("wait");
await Task.Delay(20000);
Console.WriteLine();

Console.WriteLine("Should pass ");
if (cache.AddToCache(key1, seconds))
{
    Console.WriteLine($"pass {key1}");
}
else
{
    Console.WriteLine($"fail {key1}");
}



Console.WriteLine("********************************************");
Console.WriteLine("********************************************");
Console.WriteLine("Press enter to start <T> test");
Console.ReadLine();


seconds = 3;
var key3 = "Test3";


Console.WriteLine("Should pass ");
if (cache.AddToCache<string>(key3, "test3value", seconds))
{
    Console.WriteLine($"pass {key3}");
}
else
{
    Console.WriteLine($"fail {key3}");
}

var val = cache.GetFromCache<string>(key3);
if (val == null)
{
    Console.WriteLine($"{key3} is null - something is wrong");
}
else
{
    Console.WriteLine($"{key3} = {val}. This is correct!");
}


var key4 = "Test4";

Console.WriteLine("Should pass ");
if (cache.AddToCache<string>(key4, "test4value", seconds))
{
    Console.WriteLine($"pass {key4}");
}
else
{
    Console.WriteLine($"fail {key4}");
}


await Task.Delay(1000);
Console.WriteLine();

Console.WriteLine("Should fail ");
if (cache.AddToCache<string>(key3, "test3value", seconds))
{
    Console.WriteLine($"pass {key3}");
}
else
{
    Console.WriteLine($"fail {key3}");
}



Console.WriteLine();
Console.WriteLine("wait");
await Task.Delay(20000);


var va2 = cache.GetFromCache<string>(key3);
if(va2 == null)
{
    Console.WriteLine($"{key3} is null");
}
else
{
    Console.WriteLine($"{key3} is has a value - this shouldn't happen!");
}



Console.WriteLine("Should pass ");
if (cache.AddToCache<string>(key3, "test3value", seconds))
{
    Console.WriteLine($"pass {key3}");
}
else
{
    Console.WriteLine($"fail {key3}");
}