Answers for "ASP.NET Core set update clear cache from IMemoryCache (set by Set method of CacheExtensions class)"

ASP.NET Core set update clear cache from IMemoryCache (set by Set method of CacheExtensions class)

serviceCollection.AddSingleton<IMyCache, MyMemoryCache>();

ASP.NET Core set update clear cache from IMemoryCache (set by Set method of CacheExtensions class)

Internally it uses IMemoryCache.
Use case is exactly the same with 2 additional features:

Clear all items from memory cache
Iterate through all key/value pairs
You have to register singleton:

serviceCollection.AddSingleton<IMyCache, MyMemoryCache>();
Use case:

public MyController(IMyCache cache)
{
    this._cache = cache;
}

[HttpPut]
public IActionResult ClearCache()
{
    this._cache.Clear();
    return new JsonResult(true);
}

[HttpGet]
public IActionResult ListCache()
{
    var result = this._cache.Select(t => new
    {
        Key = t.Key,
        Value = t.Value
    }).ToArray();
    return new JsonResult(result);
}

ASP.NET Core set update clear cache from IMemoryCache (set by Set method of CacheExtensions class)

serviceCollection.AddSingleton<IMyCache, MyMemoryCache>();

public interface IMyCache : IEnumerable<KeyValuePair<object, object>>, IMemoryCache
{
    /// <summary>
    /// Clears all cache entries.
    /// </summary>
    void Clear();
}

public class MyMemoryCache : IMyCache
{
    private readonly IMemoryCache _memoryCache;
    private readonly ConcurrentDictionary<object, ICacheEntry> _cacheEntries = new ConcurrentDictionary<object, ICacheEntry>();

    public MyMemoryCache(IMemoryCache memoryCache)
    {
        this._memoryCache = memoryCache;
    }

    public void Dispose()
    {
        this._memoryCache.Dispose();
    }

    private void PostEvictionCallback(object key, object value, EvictionReason reason, object state)
    {
        if (reason != EvictionReason.Replaced)
            this._cacheEntries.TryRemove(key, out var _);
    }

    /// <inheritdoc cref="IMemoryCache.TryGetValue"/>
    public bool TryGetValue(object key, out object value)
    {
        return this._memoryCache.TryGetValue(key, out value);
    }

    /// <summary>
    /// Create or overwrite an entry in the cache and add key to Dictionary.
    /// </summary>
    /// <param name="key">An object identifying the entry.</param>
    /// <returns>The newly created <see cref="T:Microsoft.Extensions.Caching.Memory.ICacheEntry" /> instance.</returns>
    public ICacheEntry CreateEntry(object key)
    {
        var entry = this._memoryCache.CreateEntry(key);
        entry.RegisterPostEvictionCallback(this.PostEvictionCallback);
        this._cacheEntries.AddOrUpdate(key, entry, (o, cacheEntry) =>
        {
            cacheEntry.Value = entry;
            return cacheEntry;
        });
        return entry;
    }

    /// <inheritdoc cref="IMemoryCache.Remove"/>
    public void Remove(object key)
    {
        this._memoryCache.Remove(key);
    }

    /// <inheritdoc cref="IMyCache.Clear"/>
    public void Clear()
    {
        foreach (var cacheEntry in this._cacheEntries.Keys.ToList())
            this._memoryCache.Remove(cacheEntry);
    }

    public IEnumerator<KeyValuePair<object, object>> GetEnumerator()
    {
        return this._cacheEntries.Select(pair => new KeyValuePair<object, object>(pair.Key, pair.Value.Value)).GetEnumerator();
    }

    IEnumerator IEnumerable.GetEnumerator()
    {
        return this.GetEnumerator();
    }

    /// <summary>
    /// Gets keys of all items in MemoryCache.
    /// </summary>
    public IEnumerator<object> Keys => this._cacheEntries.Keys.GetEnumerator();
}

public static class MyMemoryCacheExtensions
{
    public static T Set<T>(this IMyCache cache, object key, T value)
    {
        var entry = cache.CreateEntry(key);
        entry.Value = value;
        entry.Dispose();

        return value;
    }

    public static T Set<T>(this IMyCache cache, object key, T value, CacheItemPriority priority)
    {
        var entry = cache.CreateEntry(key);
        entry.Priority = priority;
        entry.Value = value;
        entry.Dispose();

        return value;
    }

    public static T Set<T>(this IMyCache cache, object key, T value, DateTimeOffset absoluteExpiration)
    {
        var entry = cache.CreateEntry(key);
        entry.AbsoluteExpiration = absoluteExpiration;
        entry.Value = value;
        entry.Dispose();

        return value;
    }

    public static T Set<T>(this IMyCache cache, object key, T value, TimeSpan absoluteExpirationRelativeToNow)
    {
        var entry = cache.CreateEntry(key);
        entry.AbsoluteExpirationRelativeToNow = absoluteExpirationRelativeToNow;
        entry.Value = value;
        entry.Dispose();

        return value;
    }

    public static T Set<T>(this IMyCache cache, object key, T value, MemoryCacheEntryOptions options)
    {
        using (var entry = cache.CreateEntry(key))
        {
            if (options != null)
                entry.SetOptions(options);

            entry.Value = value;
        }

        return value;
    }

    public static TItem GetOrCreate<TItem>(this IMyCache cache, object key, Func<ICacheEntry, TItem> factory)
    {
        if (!cache.TryGetValue(key, out var result))
        {
            var entry = cache.CreateEntry(key);
            result = factory(entry);
            entry.SetValue(result);
            entry.Dispose();
        }

        return (TItem)result;
    }

    public static async Task<TItem> GetOrCreateAsync<TItem>(this IMyCache cache, object key, Func<ICacheEntry, Task<TItem>> factory)
    {
        if (!cache.TryGetValue(key, out object result))
        {
            var entry = cache.CreateEntry(key);
            result = await factory(entry);
            entry.SetValue(result);
            entry.Dispose();
        }

        return (TItem)result;
    }
}