GetOrCreateAync for IDistributedCache

DistributedCacheExtensions.cs

using System;
using System.IO;
using System.Text.Json;
using System.Threading.Tasks;

namespace Microsoft.Extensions.Caching.Distributed
{
    public static class DistributedCacheExtensions
    {
        public static async Task<T> GetOrCreateAsync<T>(this IDistributedCache cache,
            string key,
            Func<Task<T>> factory,
            DistributedCacheEntryOptions options = null)
        {
            if (cache == null)
                throw new ArgumentNullException(nameof(cache));
            if (key == null)
                throw new ArgumentNullException(nameof(key));
            if (factory == null)
                throw new ArgumentNullException(nameof(factory));
            T value;
            var bytes = await cache.GetAsync(key).ConfigureAwait(false);
            if (bytes == null)
            {
                value = await factory().ConfigureAwait(false);
                await cache.SetAsync(key,
                    JsonSerializer.SerializeToUtf8Bytes(value),
                    options ?? new DistributedCacheEntryOptions()).ConfigureAwait(false);
            }
            else
            {
                using var utf8Json = new MemoryStream(bytes);
                value = await JsonSerializer.DeserializeAsync<T>(utf8Json).ConfigureAwait(false);
            }
            return value;
        }
    }
}