llorch19/aspect-injector

AOP framework for .NET (c#, vb, etc)

Aspect Injector

Aspect Injector is an attribute-based framework for creating and injecting aspects into your .net assemblies.

Project Status

Download

> dotnet add package AspectInjector

Features

• Compile-time injection - works with Blazor and AOT
• Injecting Before, After and Around (wrap) Methods, Constructors, Properties and Events
• Injecting Interface implementations
• Supports any project that can reference netstandard2.0 libraries, see here
• Debugging support
• Roslyn analyzers for your convenience (only c# currently)

Check out samples and docs

Requirements

• .NetCore runtime 2.1.6+ installed on your machine (your projects can be anything that can reference netstandard2.0)
• (optional) For analyzers to work in VSCode, don't forget to enable "omnisharp.enableRoslynAnalyzers": true

Known Issues / Limitations

• 'Edit and Continue' feature in VS is not working at the moment with .netcore3+ #138
• Unsafe methods are not supported and are silently ignored.
• Until Nuget v5 (with transient build feature) you need to refrecence AspectInjector into every project in your solution. Thus,

    if VisualStudio >= 2019 && CoreSDK >= 2.1.602
        no worries about references
    else 
        reference AspectInjector directly to projects where aspects are defined or used

Simple advice

Create an aspect with simple advice:

[Aspect(Scope.Global)]
[Injection(typeof(LogCall))]
public class LogCall : Attribute
{
    [Advice(Kind.Before)] // you can have also After (async-aware), and Around(Wrap/Instead) kinds
    public void LogEnter([Argument(Source.Name)] string name)
    {
        Console.WriteLine($"Calling '{name}' method...");   //you can debug it	
    }
}

Use it:

[LogCall]
public void Calculate() 
{ 
    Console.WriteLine("Calculated");
}

Calculate();

Result:

$ dotnet run
Calling 'Calculate' method...
Calculated

Simple mixin

Create an aspect with mixin:

public interface IInitializable
{
    void Init();
}

[Aspect(Scope.PerInstance)]
[Injection(typeof(Initializable))]
[Mixin(typeof(IInitializable))]
public class Initializable : IInitializable, Attribute
{
    public void Init()
    {
        Console.WriteLine("Initialized!");
    }
}

Use it:

[Initializable]
public class Target
{ 
}

var target = new Target() as IInitializable;
target.Init();

Result:

$ dotnet run
Initialized!