Unity InterfacesInterceptor in .NET Core

Question

I'll start out with the questions first and follow up with context:

Is there a version of Unity.Interception available that is compatible with .NET Core?
Is there a .NET Core compatible alternative to Unity.Interception?

I am looking at using the Microsoft.Practices.Unity.InterceptionExtension.InterfaceInterceptor to short-circuit calls to certain interfaces (example code below), but it seems that the suggested NuGet package, Unity.Interception 4.0.1, is not compatible with .NET Core.

I have made an attempt to shoe-horn in the usage of Unity.Interception 4.0.1, as the code snippets used works fine in classic .NET; but as mentioned I am running into problems with .NET Core:

Install-Package : Package Unity.Interception 4.0.1 is not compatible with netcoreapp1.1 (.NETCoreApp,Version=v1.1). Package Unity.Interception 4.0.1 supports: net45 (.NETFramework,Version=v4.5 )

I tried to circumvent this by adding net451 to the PackageTargetFallback list:

<PackageTargetFallback>$(PackageTargetFallback);net451;dnxcore50;portable-net451+win8</PackageTargetFallback>

This allowed me to install the package, but it then complains something fierce about needing a reference to mscorlib:

Error CS0012
The type 'Type' is defined in an assembly that is not referenced. You must add a reference to assembly 'mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'.

I'm not going to attempt to reference in the Classic .NET framework into a .NET Core application, so I'm pretty much at a dead end here.

Example code:

public class Interceptions
{
    public static object CreateCustomInterceptedProxy(Type type)
    {
        var interceptor = new InterfaceInterceptor();

        var proxy = interceptor.CreateProxy(type, null);

        var interceptionBehavior = new CustomInterceptionBehavior();

        proxy.AddInterceptionBehavior(interceptionBehavior);

        return proxy;
    }
}

public class CustomInterceptionBehavior : IInterceptionBehavior
{
    public IMethodReturn Invoke(IMethodInvocation input, GetNextInterceptionBehaviorDelegate getNext)
    {
        object response = null; // replace with stuff that builds an actual object

        return input.CreateMethodReturn(response, new object[] { });
    }

    public IEnumerable<Type> GetRequiredInterfaces()
    {
        return Type.EmptyTypes;
    }

    public bool WillExecute => true;
}

score 2 · Answer 1 · answered Jul 27 '17 at 15:56

I know the question is for around a month ago, but I thought it might be useful for other developers as well (because It's been a nightmare for me). I have forked out Unity project and ported that to .Net Core 2.0. You can find it under this repository:

https://github.com/Chavoshi/Unity.NetCore

And also these are the nuget packages:

https://www.nuget.org/packages/Unity.NetCore/

https://www.nuget.org/packages/Unity.Interception.NetCore/

P.S: The only part which I was not able to port is TransparentProxyInterception that uses .Net Remoting which is totally discontinued in .Net Core.

Thanks for the feedback, and for making the effort to port Unity to .NET Core! Though we landed on an acceptable workaround this time, it's good to know there are now more options available when we step up our game to 2.0 — Sigurd Garshol, Jul 29 '17 at 08:20

score 1 · Answer 2 · answered Sep 03 '20 at 07:44

1

Unfortunately you have to use 3rd party libraries like:

Unity fork: https://www.nuget.org/packages/Unity.Interception.NetCore/
Dora Interception: https://www.nuget.org/packages/Dora.Interception/ it has a detailed usage documentation here.

answered Sep 03 '20 at 07:44

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score 0 · Accepted Answer · answered Jun 16 '17 at 15:22

It seems Castle.Core's DynamicProxy is what I needed:

using Castle.DynamicProxy;

public class CustomInterceptor : IInterceptor
{
    public static object CreateCustomInterceptedProxy(Type type)
    {
        var proxyGenerator = new ProxyGenerator();

        var interceptor = new Interceptor();

        var proxy = proxyGenerator.CreateInterfaceProxyWithoutTarget(type, interceptor);

        return proxy;
    }
}

public class CustomInterceptor : IInterceptor
{
    public void Intercept(IInvocation invocation)
    {
        object returnValue; // Do stuff to populate return value

        invocation.ReturnValue = returnValue;
    }
}

Unity InterfacesInterceptor in .NET Core

Example code:

3 Answers3