Pass over the handler instance to the middleware

Sometimes you want the actual instance of the handler in the middleware (Pipeline behaviour), for example to read class attributes or check if it implements a particular interface

Can the Mediatr be extended to pass the handler instance?

var handlerInstance = GetHandler<IRequestHandler<TRequest, TResponse>>(serviceFactory);
Task<TResponse> Handler() => handlerInstance.Handle((TRequest) request, cancellationToken);
            return serviceFactory
                .GetInstances<IPipelineBehavior<TRequest, TResponse>>()
                .Reverse()
                .Aggregate((RequestHandlerDelegate<TResponse>) Handler, (next, pipeline) => () => pipeline.Handle((TRequest)request, cancellationToken, next, handlerInstance))();

[jbogard]

Mainly because it’s easier to take a dependency on IUserContext or similar than it is to have essentially traits/mixins with interfaces and relying on generic constraints to get things wired up correctly. You’ll have fewer headaches just supplying your handlers with dependencies than trying to have them wired up directly.

[jbogard]

If you’re trying to go the property injection route, setting state on your handlers themselves, I’d strongly caution you against that. At most, I’d set state on shared services, not on a handler itself.