logging w/ CBO

cbo.cs

// license:cc0, free to use.

void Main()
{
    var x = new Test();
    x.Foo();
    x.Bar();
}

[Logging]
public class Test
    : ContextBoundObject
{
    public void Foo()
    {
        Console.WriteLine("foo!");
    }
    
    public void Bar()
    {
        Console.WriteLine("bar!");
    }
}

public class LoggingProxy : RealProxy
{
    private readonly MarshalByRefObject _obj;
    
    private readonly Action<IMethodCallMessage> _beforeCall;
    
    private readonly Action<IMethodCallMessage> _afterCall;

    public LoggingProxy(Type type, MarshalByRefObject obj, Action<IMethodCallMessage> beforeCall, Action<IMethodCallMessage> afterCall)
        : base(type)
    {
        this._obj = obj;
        this._beforeCall = beforeCall;
        this._afterCall = afterCall;
    }

    public override IMessage Invoke(IMessage msg)
    {
        var ccm = msg as IConstructionCallMessage;
        if (ccm != null)
        {
            RemotingServices.GetRealProxy(this._obj).InitializeServerObject(ccm);
            return EnterpriseServicesHelper.CreateConstructionReturnMessage(
                ccm, (MarshalByRefObject) this.GetTransparentProxy()
            );
        }
        var mcm = msg as IMethodCallMessage;
        if (mcm != null)
        {
            this._beforeCall(mcm);
            var ret = RemotingServices.ExecuteMessage(this._obj, mcm);
            this._afterCall(mcm);
            return ret;
        }
        throw new NotSupportedException();
    }
}

[AttributeUsage(AttributeTargets.Class)]
public class LoggingAttribute : ProxyAttribute
{
    public override MarshalByRefObject CreateInstance(Type serverType)
    {
        var obj = base.CreateInstance(serverType);
        var proxy = new LoggingProxy(
            serverType,
            obj,
            m => Debug.WriteLine("ENTER " + m.MethodName),
            m => Debug.WriteLine("LEAVE " + m.MethodName)
        );
        return (MarshalByRefObject) proxy.GetTransparentProxy();
    }
}

stdout.txt

ENTER Foo
foo!
LEAVE Foo
ENTER Bar
bar!
LEAVE Bar