Skip to main content

OWIN and Katana

OWIN and Katana. This two words are now the buzz words in Web development over Microsoft technologies. I heard pretty often this two buzz words used, but without knowing very clear what is OWIN and what is Katana. The main scope of this post is to define this two new terms and determine when we should talk about OWN and when we should talk about Katana.
OWIN comes from Open Web Interface for .NET and is an abstraction level between our web application and .NET web server infrastructure. This mean that from now on we will be able to host our web applications on different web servers, not only on IIS.
Until now the only possibility to host a web application written in .NET was using IIS. OWIN is here to help us. Because OWN define the abstraction level between the web server and web application we can now start to develop owner own web servers or integrate it in existing one.
It is important to know that OWIN only defines the specification of this layer and not the real implementation. Based on this specification we can create and integrate a middleware layer between our web application and the request/response. For example in this way we can change the request before arriving to our web application without having to change our web application or create a custom component for IIS (creating a custom component for IIS is not wrong, but cannot be reused on other web servers).
Katana comes with the implementation of web server made by Microsoft. It represents only an implementation of OWIN that can be used to host our web application. I expect in the future to see different implementation of OWIN for Mono that will run on Linux system and why not on Android.
I think that most of us already saw the demo where using OWIN we were able to self-host a web application in a console application. Using Katana we can do a lot of crazy things and we will be able to create and deploy different tools and web application faster and easily and we don’t need IIS anymore to host web application.
This is great especially in the development and testing step, where managing 3-5 versions of the application could be pretty complicated.
Porting between different platforms is pretty cool for small and simple application. Think about the following scenario. We create a web application that can be used in our home to search pictures shared in our network. We will be able to develop in in .NET and hosting it on a Raspberry PI using Mono.
Another good example is related to Authentication, that can be done now very easily over OWIN. We can support now Facebook, Google and other providers extremely simple.
Why we should use Katana? Well, we don’t need. It is optionally, but using Katana we will have more flexibilities because of OWIN specification. Also, expect that in the future, to see and hear about Katana more and more often.
Now with OWIN we can:

In conclusion. OWIN is the abstraction level between our web application and web server. Katana is the implementation of OWIN made by Microsoft.


Popular posts from this blog

How to check in AngularJS if a service was register or not

There are cases when you need to check in a service or a controller was register in AngularJS.
For example a valid use case is when you have the same implementation running on multiple application. In this case, you may want to intercept the HTTP provider and add a custom step there. This step don’t needs to run on all the application, only in the one where the service exist and register.
A solution for this case would be to have a flag in the configuration that specify this. In the core you would have an IF that would check the value of this flag.
Another solution is to check if a specific service was register in AngularJS or not. If the service was register that you would execute your own logic.
To check if a service was register or not in AngularJS container you need to call the ‘has’ method of ‘inhector’. It will return TRUE if the service was register.
if ($injector.has('httpInterceptorService')) { $httpProvider.interceptors.push('httpInterceptorService&#…

ADO.NET provider with invariant name 'System.Data.SqlClient' could not be loaded

Today blog post will be started with the following error when running DB tests on the CI machine:
threw exception: System.InvalidOperationException: The Entity Framework provider type 'System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer' registered in the application config file for the ADO.NET provider with invariant name 'System.Data.SqlClient' could not be loaded. Make sure that the assembly-qualified name is used and that the assembly is available to the running application. See for more information. at System.Data.Entity.Infrastructure.DependencyResolution.ProviderServicesFactory.GetInstance(String providerTypeName, String providerInvariantName) This error happened only on the Continuous Integration machine. On the devs machines, everything has fine. The classic problem – on my machine it’s working. The CI has the following configuration:

TeamCity.NET 4.51EF 6.0.2VS2013
It seems that there …

[Post-Event] Codecamp Conference Cluj-Napoca - Nov 19, 2016

Last day I was invited to another Codecamp Conference, that took place in Cluj-Napoca. Like other Codecamp Conferences, the event was very big, with more than 1.000 participants and 70 sessions. There were 10 tracks in parallel, so it was pretty hard to decide at  what session you want to join.
It was great to join this conference and I hope that you discovered something new during the conference.
At this event I talked about Azure IoT Hub and how we can use it to connect devices from the field. I had a lot of demos using Raspberry PI 3 and Simplelink SensorTag. Most of the samples were written in C++ and Node.JS and people were impressed that even if we are using Microsoft technologies, we are not limited to C# and .NET. World and Microsoft are changing so fast. Just looking and Azure IoT Hub and new features that were launched and I'm pressed (Jobs, Methods, Device Twin).
On backend my demos covered Stream Analytics, Event Hub, Azure Object Storage and DocumentDB.

What abo…