Open Web Interface for .NET (OWIN)

Inspired by a recent talk from DDDEA

OWIN

• Defines a standard way of communicating between hosts, servers and web frameworks
• Found in the Owin.* namespace

Katana

• Microsoft's implementation of components to help build and host OWIN-based applications
• Found in the Microsoft.Owin.* namespace

OWIN Format

1000 words (part 2)

1000 words (part 3)

Middleware Demo

Show me the code!

Why is it important?

• ASP.NET MVC vNext adds support for OWIN
• Web API already supports OWIN, will get merged with MVC in vNext
• Create lightweight, modular, portable apps using only parts of the .NET Framework you need (e.g. no more System.Web)
• An xcopy-able web app (Roslyn, Katana, Core CLR, "K" runtime)
• IIS major versions are tied to OS (IIS 8)
• Web sockets are only supported in IIS 8 / Win 8
• Can pick-and-mix components and frameworks and have them play nicely together (self-host)
• The hosting environment gets out of the way (Linux / Mono)
• Testability

Real-world Use Case: Installers

• Installing IIS is difficult
• Deployment Image Management Service (DISM.exe) vs Package Manager (pkgmgr.exe)
• Requires elevated permissions
• requires a reboot mid-way through installation process
• Difficult to maintain