FluentCache

A Library for Fluent Caching in C#

FluentCache is a simple, fluent library to help you write clean, legible caching code by reducing boilerplate.

double ezResult = cache.Method(r => r.DoSomeHardParameterizedWork(parameter))
                       .GetValue();

Package	Status
FluentCache
FluentCache.RuntimeCaching
FluentCache.Microsoft.Extensions.Caching.Abstractions
FluentCache.Microsoft.Extensions.Caching.Memory
FluentCache.Microsoft.Extensions.Caching.Redis

Features:

• Fluent API: clean, simple API to encapsulate caching logic
• Automatic Cache Key Generation: refactor at will and never worry about magic strings. FluentCache automatically analyzes the expression tree and generates caching keys based on the type, method, and parameters
• Caching policies: specify caching policies like expiration, validation, and error handling
• Cache Implementations: FluentCache supports common caching implementations and has a simple ICache interface to support other providers

Here's an example of some typical caching code that can be replaced by FluentCache:

//retrieve a value from the cache. If it's not there, load it from the repository 
var repository = new Repository();
int parameter = 5;
string region = "FluentCacheExamples";
string cacheKey = "Samples.DoSomeHardParameterizedWork." + parameter;

CachedValue<double> cachedValue = cache.Get<double>(cacheKey, region);
if (cachedValue == null)
{
    double val = repository.DoSomeHardParameterizedWork(parameter);
    cachedValue = cache.Set<double>(cacheKey, region, val, new CacheExpiration());
}
double result = cachedValue.Value;

There are several issues with this code:

• boilerplate: duplicating this code is tedious
• magic strings: the cache key is based on magic strings that won't automatically refactor as methods and parameters change
• hard to read: the intent is overwhelmed by the mechanics

Examples:

Cache Expiration Policies

double ttlValue = cache.Method(r => r.DoSomeHardWork())
                       .ExpireAfter(TimeSpan.FromMinutes(5))
                       .GetValue();

Async/Await Retrieval

double asyncValue = await cache.Method(r => r.DoSomeHardWorkAsync())
                               .GetValueAsync();

Validation Strategies

double onlyCachePositiveValues = cache.Method(r => r.DoSomeHardWork())
                                      .InvalidateIf(cachedVal => cachedVal.Value <= 0d)
                                      .GetValue();

Clearing Values

cache.Method(r => r.DoSomeHardParameterizedWork(parameter))
     .ClearValue();

Getting Started

Hello World

To get started, we will use the FluentDictionaryCache to illustrate the various Fluent extension methods provided by the API

//use the simplest cache, which wraps a dictionary
//other cache implementations are provided in additional nuget packages
ICache myCache = new FluentCache.Simple.FluentDictionaryCache();

//create a wrapper around our Repository
//wrapper will allow us to cache the results of various Repository methods
Repository repo = new Repository();
Cache<Repository> myRepositoryCache = myCache.WithSource(repo);

//create and execute a CacheStrategy using Fluent Extension methods
string resource = myRepositoryCache.Method(r => r.RetrieveResource())
                                   .ExpireAfter(TimeSpan.FromMinutes(30))
                                   .GetValue();

Implementations

Cache Implementation	FluentCache Type	NuGet Package
ConcurrentDictionary	FluentDictionaryCache	FluentCache
System.Runtime.Caching.MemoryCache	FluentMemoryCache	FluentCache.RuntimeCaching
Microsoft.Extensions.Caching.Memory.MemoryCache	FluentMemoryCache	FluentCache.Microsoft.Extensions.Caching.Memory
Microsoft.Extensions.Caching.Redis.RedisCache	FluentRedisCache	FluentCache.Microsoft.Extensions.Caching.Redis
Microsoft.Extensions.Caching.Memory.IMemoryCache	FluentIMemoryCache	FluentCache.Microsoft.Extensions.Caching.Abstractions
Microsoft.Extensions.Caching.Distributed.IDistributedCache	FluentIDistributedCache	FluentCache.Microsoft.Extensions.Caching.Abstractions

Other caches can implement the FluentCache.ICache interface

New in v4

1. Support for .NET Standard 2.0
2. New implementations for Microsoft.Extensions.Caching
   1. Microsoft.Extensions.Caching.Memory.IMemoryCache added to FluentCache.Microsoft.Extensions.Caching.Abstractions nuget package
   2. Microsoft.Extensions.Caching.Memory.MemoryCache added to FluentCache.Microsoft.Extensions.Caching.Memory nuget package
   3. Microsoft.Extensions.Caching.Distributed.IDistributedCache added to FluentCache.Microsoft.Extensions.Caching.Abstractions nuget package
   4. Microsoft.Extensions.Caching.Redis.RedisCache added to FluentCache.Microsoft.Extensions.Caching.Redis nuget package
3. Support for caching methods on generic repositories

The previous FluentCache.Redis package is deprecated in favor of FluentCache.Microsoft.Extensions.Caching.Redis