My understanding is currently you can self host WebAPI using Katana, and MVC will have this capability in a future version. Essentially Katana will be a hosting option available to both MVC and WebAPI.
Kestrel has entered the picture, and I see a few MS employees blogging about it demonstrating hosting ASP.NET vNext on Linux.
My understanding is that both Kestrel and Katana implement the OWIN pipeline.
From there it is all a bit fuzzy. I ask myself, why has Kestrel entered the picture, when it seems Katana could serve the same purpose if you compiled it with mono and made some efforts to make it cross platform compatible(perhaps easier said than done).
Do Kestrel and Katana serve the same purpose? Or is one specialized in some way that the other is not?
Will Kestrel eventually be a viable choice for Windows deployments? Or will it be specialized for non-Windows environments and Katana still the choice for Windows?
I recognize that I'm possibly asking for an apple to oranges comparison due to my lack of knowledge of Katana/Kestrel, but if the answer is "Oranges have more of an acidic taste than apples" then that IMO is a perfectly valid answer.
Katana is Microsoft's OWIN implementation and also includes some middleware components for security/authentication, serving static files, and a few other things.
Kestrel is Microsoft's cross-platform development web server that can be used with ASP.NET 5.
ASP.NET 5 does not implement OWIN, but has a "bridge" to enable OWIN components to be used in ASP.NET 5 applications, including running on Kestrel.
I still don't get a clear picture after reading other answers under this question, so I made some research and here's my conclusion:
OWIN is a specification, which defines an programming interface between a web server(like Kestrel and the ones provided by Katana) and a web application(the code by you).
Kestrel comes from ASP.NET Core. It's a OWIN compatible web server.
Katana comes from ASP.NET 4.X. It's a set of things of Microsoft's OWIN implementation, including OWIN servers.
Last but not least:
ASP.NET 5 is dead and replaced by ASP.NET Core. So don't mention it any more.
(Update at 2019/06/28: "Today, we’re announcing that the next release after .NET Core 3.0 will be .NET 5" - BY MS https://devblogs.microsoft.com/dotnet/introducing-net-5/. That means there will be ASP.Net 5, which is in fact the next generation of ASP.Net Core)
OWIN is the key/essential thing in both ASP.NET 4.X and ASP.NET Core.
For more, you may read https://www.quora.com/Is-ASP-NET-Core-a-replacement-for-OWIN-Katana
May be an old question, but since a quick google search led me here i think no one else asked a similar question.
Quoting ASP.NET 5 Documentation:
Kestrel
Kestrel is a cross-platform web server based on libuv, a cross-platform asynchronous I/O library. Kestrel is open-source, and you can view the Kestrel source on GitHub. You add support for Kestrel by including “Kestrel” in your project’s dependencies listed in project.json.
Choosing a server
If you intend to deploy your application on a Windows server, you should run IIS as a reverse proxy server that manages and proxies requests to Kestrel. If deploying on Linux, you should run a comparable reverse proxy server such as Apache or Nginx to proxy requests to Kestrel.
For self-hosting scenarios, such as running in Service Fabric, we recommend using Kestrel without IIS. However, if you require Windows Authentication in a self-hosting scenario, you should choose WebListener.
So, my understanding is: If Kestrel was only a development server, its not anymore and is somehow replacing Katana and OWIN.
"Project Katana" includes Microsoft adding support to IIS for OWIN, creating OwinHost.exe, and providing libraries to allow application to interface with a self hosting WebAPI. Some of these libraries such as Microsoft.Owin.Security are used by ASP.NET MVC 5 (not ASP.NET Core) to wire up identity/authentication through OWIN, but MVC 5 does not support self hosting(although it is possible using other tools). The SelfHosting library is only intended for WebAPI.
So "Katana" is a broad term referring to both host implementations as well as web application support for OWIN: "These components include both infrastructure components, such as hosts and servers, as well as functional components, such as authentication components and bindings to frameworks such as SignalR and ASP.NET Web API."
You may see phrases like "Migrate from Katana to ASP.NET Core" which refere to the web application side. Meaning abandoning the Microsoft.Owin libraries, and using ASP.NET Core which has full OWIN support built in without the need for additional libraries. Or you may see a similar phrase which means moving off of a Katana host to another host such as Kestrel. Unfortunately the term is used to refere to either side of the implementation with little clarification, and you'll have to pay attention to the context of the discussion.
Kestrel is just a host implementation. Its goal is to provide OWIN hosting support across many platforms. It is more lightweight, and not as full featured or mature as IIS. It is recommended to use it behind a reverse proxy of a more secure and rebust web server such as IIS, Apache, nginx, or other. Kestrel is what Microsoft's current documentation recommends as a host to deploy ASP.NET Core web application's on other platforms such as Linux.
If you create an ASP.Net Core project, then Kestrel is currently included by default. It is supported on the same platforms that ASP.NET Core supports.
Related
We have a big ASP.NET Framework application hosted in IIS and we are considering a progressive migration to ASP.NET Core using YARP, as explained here: https://devblogs.microsoft.com/dotnet/incremental-asp-net-to-asp-net-core-migration/
The basic idea is to deploy a ASP.NET Core app that will proxy all the requests to the old application, and then move the code progressively from the legacy app to the proxy, until the legacy app is empty and can be removed.
We are wondering about the hosting of the ASP.NET Core proxy app. In priciple there is no limitation, it could be deployed in IIS alongside with the legacy app or be deployed with Docker/Kubernetes. However, we don't know if that second option will cause a performance penalty or any other kind of problem. So before doing a POC, we'd like to ask if somebody has experience with this problem and some advice about it.
So I am playing around with Service Fabric for rolling out a system to the cloud, and so far I have most of the stateless services ported over and running well using ASP.NET Core.
I have another set of services that need to be stateful, and I would like to leverage .NET Core for those services as well. For those I will need to run a custom TCP protocol, not HTTP/WebAPI/WCF.
So the question is; is this possible? The templates only have a ASP.NET Core stateless service template. Can I build something like a .NET Core console application to run as a "Reliable Service"? If so, is there any documentation on how to do this?
Yes, it's possible.
You can create the .NET 4.5.1 stateful service via the template, and then port that project to .NET Core - we've done this and it works just fine.
There doesn't appear to be any official documentation on this process.
If I understand correctly part of the motivation of ASP.NET vNext is to reduce overhead. An MVC6 application can be self hosting. My question is what is the best practice way of hosting a ASP.NET vNext application. Is there something similar to the WCF activation services that monitor the health of the service or is there some way of doing this from within the application?
The "best" way to host ASP.NET MVC 6 is to choose the way that best matches your app's needs, of course! But that perhaps isn't so helpful as far as advice goes.
First, you need to consider the requirements of the application, such as:
Does it need to run cross-platform?
Does it need health management?
Does it need to use existing IIS modules?
Does it need to run in the context of another application?
Does it need to use Windows Authentication?
And no doubt many more requirements...
Here's a brief summary of the various hosting options and their pros/cons:
IIS is perhaps the most well-known host. It has been hardened for well over a decade. Many popular modules are available for it, including providing various security features. IIS has built-in support for Windows Authentication, logging, app warmup, health management, remote administration, and lots of other features.
IIS Express shares the same codebase as IIS, but can be run without admin privileges.
Kestrel is a cross-platform web server that is being written as part of ASP.NET 5 and is currently most suited for development work. It's very lightweight, which can be both good (nothing in the way!) and bad (not very many features).
Self-host is where you are master of your own domain. Nearly everything is up to you, including figuring out what should happen if there is an unrecoverable error. Self-hosting is a great option if you need to host a server within your app (e.g. a client app that uses a web server to host UI or services that the app directly uses).
There is certainly no one "best" way to host an ASP.NET MVC 6 app, but there are certainly many solutions catered to a variety of needs.
In my answer to ASP.NET vNext is host agnostic, what does it deeply mean? I covered a few other aspects of host agnosticism.
ASP.NET Core 1.1 Answer
The 1.1 release added GZIP compression and response caching.
Kestrel is still not security tested and should not be used without IIS or NGINX as a reverse proxy. This will change at some point.
Kestrel still does not support HTTP 2.0.
Using IIS or NGINX with MVC 6 is slower than MVC 5. Yes MVC 6 is supposed to be faster but only if you use Kestrel on it's own.
ASP.NET Core 1.0 Answer
IIS or NGINX is by far the best host for an ASP.NET MVC 6 application. Below are a list of features you will not get without IIS or NGINX without lots of extra work. Note that all of these features require a small amount of config in the web.config file.
The Kestrel web server has not been battle hardened and tested for security. It's not supposed to be exposed to the internet...yet.
Kestrel does not support HTTP 2.0.
GZIP compression of HTTP requests for saving bandwidth and better performance. This alone is a big enough reason.
Error handling outside of ASP.NET. What happens when you have a .dll file missing? Well IIS will still show an error page and you can customize the error page too.
Dynamic IP security - During a Denial of Service (DoS) attack, a very simple and small 403.501 or 403.502 Forbidden static error page is displayed.
Objective:
We have a Windows Service/generic EXE that also hosts a WCF service (.Net 3.5). I'd like to be able to take a third party ASP.NET component in a DLL, and host it through that WCF Service.
Is this possible to do, in any way?
It seems like if you want to host a ASP.NET app, it must be through IIS, but we don't use IIS.
Is there any way that we could load the ASP.NET app into memory, make the app available through an endpoint, and receive requests back from the app?
Specifically, we'd like to take the "Microsoft.ReportViewer.WebForms.dll", expose the web form in a web page, and accept any requests back from the web form.
http://msdn.microsoft.com/en-us/library/ms251723.aspx
Looking for anything to get me started. Thx.
From owin.org
"OWIN defines a standard interface between .NET web servers and web applications. The goal of the OWIN interface is to decouple server and application, encourage the development of simple modules for .NET web development, and, by being an open standard, stimulate the open source ecosystem of .NET web development tools."
Essentially Owin implementations, like Katana (OWIN implementations for Microsoft servers and frameworks.), help you self host web apps, even in a Windows NT Service.
According to this post, hosting a WebForms app outside IIS/ASP.NET is not possible.
WebForms are tightly coupled to ASP.NET/IIS and cannot run directly on
OWIN/Katana (e.g. outside of ASP.NET/IIS). However, you should be able
to use Katana's middleware (Security, CORS, etc.) in a WebForms
application.
http://katanaproject.codeplex.com/discussions/571291
I have read many articles about the OWIN and Katana projects, but I could not get the whole picture of it.
For a normal web developer who uses ASP.NET:
What exactly is OWIN and what problems does it solve (in simple words). What is its relation to IIS?
Does OWIN replace IIS? if not, in what situations does OWIN best fit?
How could OWIN help me in my daily work projects?
How could OWIN help me in a self-improvement projects?
Regarding the comment above, OWIN is not a framework. OWIN is a specification on how web servers and web applications should be built in order to decouple them and allow movement of ASP.NET applications to environments which were not supported before.
Prior to OWIN, when building ASP.NET application, you were inherently bound to IIS due to the heavy dependency on System.Web assembly.
System.Web is something that has existed ever since ASP (non .NET version) and internally contains many things that you might not even need (such as Web Forms or URL Authorization), which by default all run on every request, thus consuming resources and making ASP.NET applications in general lot slower than its counterparts such as Node.js for example.
OWIN itself does not have any tools, libraries or anything else. It is just a specification.
Katana on the other hand, is a fully developed framework made to make a bridge between current ASP.NET frameworks and OWIN specification. At the moment, Katana has successfully adapted the following ASP.NET frameworks to OWIN:
Web API
Signal R
ASP.NET MVC and Web Forms are still running exclusively via System.Web, and in the long run there is a plan to decouple those as well.
On the other hand, IIS is a good, resourceful host for web servers. Entire ASP.NET performance issues using IIS has deep roots in System.Web only. Up until the recent time, when deciding how will you host your web server, you had two options:
IIS
Self-Host
So if you wanted a performance, you'd go for a self-host option. If you wanted a lot of out-of-the-box features that IIS provides, you'd go for IIS but you'd lose on performance.
Now, there is a 3rd option, a Microsoft library named Helios (current codename) which intends to remove System.Web out of the way, and allow you to use IIS on more "cleaner" way, without any unnecessary libraries or modules. Helios is now in pre-release version, and is waiting for more community feedback in order to make it fully supported Microsoft product.
Hope this explanation clarifies things better for you.
EDIT (Sep 2014):
With ASP.NET vNext being in development, Katana is slowly getting retired. Version 3.0 will most likely be last major release of Katana as a standalone framework.
However, all the concepts introduced with Katana are being integrated into ASP.NET vNext, meaning that programming model will be pretty much the same. Quote from forum post made by David Fowler (Architect of ASP.NET vNext):
vNext is the successor to Katana (which is why they look so similar).
Katana was the beginning of the break away from System.Web and to more
modular components for the web stack. You can see vNext as a
continuation of that work but going much further (new CLR, new Project
System, new http abstractions).
Everything that exists today in Katana will make it's way into vNext.
EDIT (Feb 2015):
ASP.NET vNext is now known as ASP.NET 5 and will be built on top of .NET Core 5. .NET Core 5 is lightweight factored version of .NET Framework, designed to support goals of ASP.NET 5 and .NET Native. However, ASP.NET 5 will be supported by .NET Framework 4.6 as well, that should become available together with .NET Core 5. Both ASP.NET 5 and .NET Core 5 will be licensed under MIT and will accept community contributions.
EDIT (May 2015):
Additionally, ASP.NET Web API brand will be discontinued, however it's technology will be base for new ASP.NET MVC 6. Previous ASP.NET MVC versions were built by implementing IHttpHandler, an interface defined in System.Web. ASP.NET MVC 6 removes that dependency, making it portable to various platforms and web servers.
EDIT (May 2016):
ASP.NET 5 will officially be renamed to ASP.NET Core starting with Release Candidate 2 that is scheduled to be released soon. Same will apply for Entity Framework 7 which will be renamed to Entity Framework Core. More information about official announcement and reasons behind it can be found on Scott Hanselman's blog post:
ASP.NET 5 is dead - Introducing ASP.NET Core 1.0 and .NET Core 1.0
EDIT (May 2016):
With the release of Release Candidate 2, ASP.NET Core has been modified so that future web apps are actually just .NET Core console apps setup to process incoming HTTP requests. This concept makes ASP.NET Core even more aligned with approach Microsoft has taken with microservices architecture support and its implementation through Azure Service Fabric. More information on can be found on official blog post:
Announcing ASP.NET Core RC2
If I have to define OWIN for myself, that would be: "The best ideas from the Ruby and Node.js web dev communities, coming to .NET"
But this would not help any ASP.NET developer. My own definition would be something along the lines of:
OWIN defines a standard interface between .NET web servers and web applications. The goal of the OWIN interface is to decouple server and application
If I have to answer the questions you've posed, then here it is:
OWIN is an interface specification. It decouples a web applications from IIS.
If you are using ready-made components (which is what Katana is), then some parts of the application functionality are much easier to implement compared compared to old ASP.NET. Authentication with third-party identity providers (Facebook, Twitter) is one example of this.
OWIN is essentially a collection of best practices, which have been proven in web development communities. It shows a way to implement web apps which is very open to extensibility. As each web developer should constantly be on the cutting edge of new technologies, this is one way to stay up to date with the whole web development community and not just .NET. If you learn OWIN, it would be much easier to learn other web development frameworks like Express for node.js or Rack for Ruby, because the practices they use are similar.
I will try to cover it from the practical perspective.
Katana is project name to implement OWIN in Microsoft.
What exactly is OWIN and what problems does it solve (in simple words). What is its relation to IIS?
OWIN (Open Web Interface for .NET) is a standard (OWIN Specification) and Katana is .NET library, you can get nuget from here. OWIN and Katana became somewhat synonymous on the web.
Before OWIN your only option was IIS with OWIN you can use any other application (that has entry point) as web server.
Does OWIN replace IIS? if not, in what situations does OWIN best fit?
No it does not replace IIS, you can use OWIN and IIS there's Microsoft.Owin.Host.SystemWeb nuget for that. It is best fit if you want to optimise/change the way it is handled in IIS, or you want to create your custom web server out of let's say Windows Forms Application.
How could OWIN help me in my daily work projects?
It could reduce your server running costs since your web servers do not need to run on IIS (Windows) anymore (Windows servers are more expensive than Unix based ones, and you could run it on Console Application under Mono in Linux).
How could OWIN help me in a self-improvement projects?
Learning Microsoft.Owin (and other related OWIN libraries) will improve your knowledge on how HTTP communication between client and web server works.
Good read if you want to understand more on what Katana and OWIN is.
What is OWIN?
OWIN stands for Open Web Interface for .NET. OWIN is a specification that describes how web development frameworks such as ASP.NET MVC should interact with the web servers. The goal of OWIN is to decouple web applications from the web server by introducing an abstraction layer. Such an abstraction enables you to run the same application on all the web servers that support OWIN. Additionally, it simplifies the overall system because the abstraction layer can provide a lightweight infrastructure to host the applications. IIS provides a rich set of features to the web applications. However, web applications may not need all these features. It might be sufficient for them to have minimal HTTP processing capabilities. OWIN compatible host can provide such a hosting environment to these applications. Moreover, you can define a pipeline of modules that are used during the request processing. An OWIN pipeline is a chain of OWIN compatible components through which a request passes.
What is Katana?
Katana is a set of components by Microsoft built using OWIN specifications. Some of these components include Web API, ASP.NET Identity and SignalR.
Above is extract from CodeGuru Article : http://www.codeguru.com/csharp/.net/net_asp/overview-of-owin-and-katana.htm