AOP vs MVC FilterAttributes vs Interceptors

asp.net-mvc, autofac, ninject, postsharp, unity-container

Solution

It all starts with good application design. When the design of your application is correct, there will be a lot less reason for you to interact with those AOP like features that your UI framework exposes (this holds for WCF as well).

When you hide all business logic behind a generic interface for instance, and pass command messages to it (as shown in this article), your Controllers will become thin wrappers that often do not much more than execute such business command. In that case you will be able to implement authorization and exception filtering by wrapping those business operations, leaving the UI code clean and free from attributes. Wrapping those cross-cutting concerns around business operations can be done with both interception or plain old decorators. This gives you much more flexibility and keeps your design SOLID (which has a lot of less obvious long term benefits).

Although code weaving tools as PostSharp have its use, you should be careful with them. They inject code into your assembly using a post-compile process. This makes it very painful to unit test those classes without hitting those aspects. You can't easily test those classes in isolation (which is a precondition for unit testing). Making your aspects dependent on some static variable, complicates both aspects and unit tests. Static variables make it hard to run unit tests in parallel and the use of global constants will require tests to tear down the changed global setting correctly to prevent other tests from being influenced.

Although code weaving tools result in performance that is often greater than interception, there is no performance gain compared to the use of decorators.

Problem

Original source