This is part 2 of a series of posts about some fundamental changes in ASP.Net 5 that we’ll need to re-learn (or un-learn!)
This probably isn’t new news to most people since it’s really one of the fundamental shifts for ASP.Net 5 – There won’t be a System.Web DLL. Everything that you’ll install in your website will come as different, smaller, separate libraries. For example, if you want to serve static files, you’d reference the Microsoft.AspNet.StaticFiles package, if you want to use MVC, you’d include the Microsoft.AspNet.Mvc package.
Gone! YAY! :-)
Web Forms will still be a part of .Net as part of the main framework in System.Web, just not part of ASP.Net 5.
An HttpModule simply doesn’t exist in Asp.Net 5, but of course there is a new/better way to achieve this functionality, it’s called Middleware. In an HttpModule, you had to execute code based on the various stages of a request, things such as AuthenticateRequest, AuthorizeRequest, PostResolveRequestCache, and other slightly confusingly named events. This is no longer the case with Middleware, things just make sense now … everything is simply a linear execution of your code. You can have multiple middleware’s defined to execute in your application and each one is registered explicitly in your Startup.cs file. As a developer, you are in full control of what get’s executed and in what order instead of not knowing which HttpModules are executing and not really in control of their order of execution. Middleware can simply modify a request and continue calling the next one in the chain, or it can just terminate the pipeline and return a result.
And here’s a good article that explains middeware registration and the flow of control.
HttpHandlers are also a thing of the past. All they really were was a request handler that was based on a specific request path. MVC (which now also includes WebApi) has got this covered. If you really wanted, you could create middleware for this type of functionality as well but unless you require something extraordinarily complex that MVC cannot do (and it can do a lot!), I’d recommend just sticking with MVC.