Soenneker.Reflection.Cache 2.1.7

Soenneker.Reflection.Cache

The fastest .NET Reflection cache

Reflection is slow.

• If you're calling some Reflection code once, consider if creating a cache is necessary.
• If you need to call Reflection repeatedly, this library can help speed things up.

This library is attempting to be a drop-in replacement for System.Reflection and caches the results of Reflection calls (so it's going to allocate more memory). It's thread-safe and supports concurrency.

Installation

dotnet add package Soenneker.Reflection.Cache

This cache can either be added to DI like so:

public void ConfigureServices(IServiceCollection services)
{
    services.AddReflectionCacheAsSingleton(); // or AddReflectionCacheAsScoped()
}

and you could access it like:

public class MyService
{
    private readonly IReflectionCache _cache;

    public MyService(IReflectionCache cache)
    {
        _cache = cache;
    }
}

or you can instantiate it manually:

var cache = new ReflectionCache();

Usage

var type1 = Type.GetType("System.String"); // <-- regular Reflection
var type2 = cache.GetType("System.String"); // <-- cached Reflection
bool areEqual = type1 == type2; // true

Keep in mind:

cache.GetType("System.String"); // <-- as slow as regular Reflection
cache.GetType("System.String"); // <-- very fast because the first call was cached

⚠️ Important ⚠️

Be mindful of the "cache chain". Use the Cached methods and types until you need to get the final Reflection type you need from the cache.

There are two methods for most operations like this:

Type typeofString = cache.GetType("System.String"); // <-- caches, stops the cache chain
CachedType type = cache.GetCachedType("System.String"); // <-- caches, continues the cache chain

Scenario: Retrieving parameters from a method

✅ Good:

CachedType cachedType = cache.GetCachedType("System.String");
CachedMethod cachedMethodInfo = cachedType.GetCachedMethod("Intern");
ParameterInfo?[] parameters = cachedMethodInfo.GetParameters(); // < -- parameters are now cached

❌ Bad:

CachedType cachedType = cache.GetCachedType("System.String");
MethodInfo methodInfo = cachedType.GetMethod("Intern"); // <-- uh oh, a non-cached Reflection type
ParameterInfo?[] parameters = methodInfo.GetParameters(); // <-- not cached, repeat calls are slow

Notes

• Be thoughtful of your memory footprint and where/when you dispose of the cache.
• A cache removal mechanism is needing to be built yet.
• Many Reflection functionalities are not yet implemented, and could benefit from caching.
• If you see something that could be improved (performance or allocation), please open an issue or PR.
• This library is not yet battle-tested. Please use with caution.

Benchmarks (.NET 8.0)

GetType() 5,772% faster

GetProperties() 8,960% faster

GetMethods() 599% faster

GetCustomAttributes() 1,319% faster

GetMethod() 37% faster

GetMembers() 71,130% faster

GetProperty() 52% faster

GetGenericTypeDefinition() 420% faster

IsAssignableFrom() 36% faster

Notes:

• These are averages over many iterations. The first operation is going to be as slow as the Reflection it sits in front of.
• Outliers have been removed in cases BenchmarkDotnet deems necessary.