The biggest challenge many software architects face today is how to design and implement an application that can meet all version 1 requirements plus all others that can show up afterward. Maintainability has been one of the fundamental attributes of software design since the first draft of the ISO/IEC 9126 paper, back in 1991. (The paper provides a formal description of software quality and breaks it down into a set of characteristics and sub-characteristics, one of which is maintainability. A PDF version of the paper can be obtained at iso.org.) The ability to serve a customer’s present and future needs certainly isn’t a new requirement for any piece of software. However, what many Web applications require today is a subtle and short-term form of maintainability. Many times customers don’t want new functions or a different implementation of an existing feature. They just want you to add, replace, configure or remove small pieces of functionality. A typical example is when Web sites with large audiences launch specific advertising campaigns. The overall behavior of the site doesn’t change, but extra actions must be performed along with existing actions. Moreover, these changes usually aren’t persistent. They must be removed after a few weeks to then be reincorporated a few months later, be configured differently and so forth. You need the ability to program any required functionality by composing small pieces together; you need to track dependencies without greatly impacting the source code; and you need to move toward an aspect-oriented design of software. These are some of the primary reasons behind the rapid adoption of Inversion of Control (IoC) frameworks in many enterprise projects. So what’s this article all about? It isn’t meant to be a boring lecture on how software is changing today. Instead, it’s an in-depth exploration of a powerful feature of ASP.NET MVC controllers that can notably help you in the building of aspect-oriented Web solutions: ASP.NET MVC action filters. What’s an Action Filter, Anyway?
An action filter is an attribute that, when attached to a controller class or a controller method, provides a declarative means to attach some behavior to a requested action. By writing an action filter, you can hook up the execution pipeline of an action method and adapt it to your needs. In this way, you can also take out of the controller class any logic that doesn’t strictly belong to the controller. In doing so, you make this particular behavior reusable and, more importantly, optional. Action filters are ideal for implementing crosscutting concerns that affect the life of your controllers. Read more: MSDN Magazine
An action filter is an attribute that, when attached to a controller class or a controller method, provides a declarative means to attach some behavior to a requested action. By writing an action filter, you can hook up the execution pipeline of an action method and adapt it to your needs. In this way, you can also take out of the controller class any logic that doesn’t strictly belong to the controller. In doing so, you make this particular behavior reusable and, more importantly, optional. Action filters are ideal for implementing crosscutting concerns that affect the life of your controllers. Read more: MSDN Magazine
Posts
0 comments:
Post a Comment