Immediate.Cache

Creating a cache

Create a subclass of ApplicationCacheBase, which will serve as the cache for a particular handler. An example:

        [Handler]
public static partial class GetValue
{
	public sealed record Query(int Value);
	public sealed record Response(int Value);

	private static ValueTask<Response> HandleAsync(
		Query query,
		CancellationToken _
	) => ValueTask.FromResult(new Response(query.Value));
}

public sealed class GetValueCache(
	IMemoryCache memoryCache,
	Owned<IHandler<GetValue.Query, GetValue.Response>> ownedHandler
) : ApplicationCacheBase<GetValue.Query, GetValue.Response>(
	memoryCache,
	ownedHandler
)
{
	protected override string TransformKey(GetValue.Query request) =>
		$"GetValue(query: {request.Value})";
}

      

In this case, the GetValueCache class will serve as a cache for the GetValue IH handler.

# Register the Cache with DI

In your Program.cs file:

• Ensure that Memory Cache is registered, by calling:

        services.AddMemoryCache();

      

• Register Owned<> as a singleton

        services.AddSingleton(typeof(Owned<>));

      

• Register your cache service(s) as a singleton(s)

        services.AddSingleton<GetValueCache>();

      

# Retrieve Data From the Cache

Using an instance of the GetValueCache class that you have created above, you can simply call:

        var response = await cache.GetValue(request, token);

      

If there is a cached value, it will be returned; otherwise a temporary scope will be used to create the handler and execute it; and the returned value will be stored.

# Removing Data From the Cache

Using an instance of the GetValueCache class that you have created above, you can remove cached data by calling:

        await cache.RemoveValue(request);

      

# Updating Data In the Cache

Using an instance of the GetValueCache class that you have created above, you can assign cached data by calling:

        await cache.SetValue(request, response);