OWIN - Katana Web Application

OWIN defines the standard interface between .NET web servers and web applications. KATANA is OWIN implementation for Microsoft servers and frameworks.

If you are not familiar with Katana, read this article An Overview of Project Katana which talks about the history and goals behind OWIN/Katana.

In this post I want highlight Katana's architecture around decoupling host and server from the application.

Katana Architecture

Lets look at some hosting options for OWIN application

• Custom Host: You can host owin application in a console application or OwinHost (prebuilt Katana host) using Microsoft.Owin.Host.HttpListner.
• IIS: Owin applications can be hosted in IIS using Microsoft.Owin.Host.SystemWeb server package. Unfortunately with this package, you do not get a lean host as it adds the standard ASP.NET piple. Thats where Helios comes to rescue where we can get all the benefits of IIS without the traditional ASP.NET pipeline.
• Node.js: Using connect-owin middleware, we can host Owin application in Node.js too.

I have created a demo web api application which highlights how easy it is to switch between different hosts without changing your application. The source code is available here.