AutoCache 1.0.1-alpha

Why AutoCache?

Cache misses often causes a large number of requests being referred to the database at the same time, until the data is cached again. This can reduce system performance and functionality.

How it works?

With AutoCache, outdated cache keys will remain alive until they are expired. Suppose hundreds of requests arived at same time, looking for an outdated cache item. Instead of referring them to the database, all requests will get outdated data from cache and cache update task will be triggered (The database is called only once to update the cache).

With the cache key data, the expire (ttl) and outdate time of cache key, updated too.

Installation

First, install NuGet. Then, install AutoCache from the package manager console:

PM> Install-Package AutoCache

How do I get started?

public abstract class CacheAdapter
{
    public abstract Task RemoveAsync(string key);
    public abstract Task SetAsync<T>(string key, T value, DateTime expireAt);
    public abstract Task<(T, bool)> GetAsync<T>(string key);
}

First create an adapter for your caching service (or database), by inheriting from the "BaseCache" abstract class and implement abstract methods.

public class MyCacheAdapter : CacheAdapter{
    ...
}

Then instantiate your cache adapter:

ICacheAdapter cache = new MyCacheAdapter(
        serviceScopeFactory, //IServiceScopeFactory
        60000, //defaulOutdatedAtMiliSecond
        3600000); //defaultExpireAtMiliSecond

You can inject it in ConfigureServices:

services.AddSingleton<ICacheAdapter, cache>(); // your cache adapter

Now you can use it:

public interface IToDoService
{
    Task<int> GetAsync();
}

public class ToDoService: IToDoService
{
    public virtual async Task<int> GetAsync() {
        // read from DB
        throw new NotImplementedException();
    };
}

public class CachedTodoService:ToDoService
{
    private readonly ICacheAdapter _cache;
    public CachedTodoService(ICacheAdapter cache) => _cache = cache;

    public override async Task<int> GetAsync() =>
        await _cache.GetOrCreateAsync<int, IToDoService>("todo_service_cache_key",
            async (toDoService, updateIsInProgress) =>
            {
                try
                {
                    var value = await toDoService.GetAsync();
                    return (value, true);
                }
                catch (Exception ex)
                {
                    return (0, false);
                }
            });
}