Caching in ASP.NET Core with LazyCache

Luke Lowrey -

Caching is a great way to get improve the performance of your application - either enabling high load scenarios or papering over some bad code to make life bearable. I have always favoured a simple "GetOrCreate" style caching API so when I found the open source LazyCache by Alistair Crabtree I was keen to check it out.

Installing LazyCache

LazyCache describes itself as "An easy to use thread safe generics based in memory caching service with a simple developer friendly API for C#" which I would pretty much have to agree with.

The ASP.NET Core version is currently in beta (though seems to be pretty solid) and can be installed via nuget:

Install-Package LazyCache.AspNetCore -Version 2.0.0-beta03

Configure dependency injection

Once installed it can be easily made available when configuring services in startup:

services.AddLazyCache();

This will inject IAppCache throughout your application.

Here is a simplified example of using LazyCache from the homepage my Australian tech job board - Austechjobs:

Using IAppCache

IAppCache is the Lazy Cache service being injected into my class. It provides a GetOrAddAsync method that accepts:

  • A cache key which in my example is the string "HomeModel".
  • A factory to retrieve the data to be cached in the form of a function Func<ICacheEntry, Task> addItemFactory. The code in my example returns a model after making a database call (the bit I wanted to cache).
  • Options for cache length. I am using a simple sliding timespan of 12 hours.

I find the simplicity of this caching setup very pleasing. It's implementation uses Lazy<T> to ensure the factory method is only executed once. Under the hood by default LazyCache will use IMemoryCache in Microsoft.Extensions.Caching.Memory. This is implementation will only cache data on the machine it is running on. If I was running a more intensive service I would want to extend LazyCache and implement something like redis for distributed caching. The good news is because I am using IAppCache throughout my application I can change the underlying caching provider with relative ease.

💡 Want more? Check out my list of 14 .NET libraries I always recommend.