Upgrading Nancy to Version 2

Upgrading NancyAlthough there isn’t an “official” of Nancy v2 release yet, there’ is 2.0.0-clinteastwood that’s been in NuGet since Dec 12th, 2106 and as of this post has almost 200k downloads.  The primary reason for upgrading Nancy to v2 is because of its support for NETStandard 1.6 which means you can move to .NET Core.

In this demo, I’m going to be using ASP.NET Core with Owin and Nancy 2.0.0-clinteastwood to add back in the existing routing functionality that is a breaking change in v2.

Breaking Changes

There’s an upgrade notes page on the Nancy Wiki, which lists some of the breaking changes.  Although there aren’t many, and I suspect most of the work for the 2.0 release was for targeting NETStandard.

The most glaring breaking change is with routing.


Routing syntax has changed to Get("/", args => "Hello World");, these can be made async by adding the async/await keywords. For more info see the PR where it all changed https://github.com/NancyFx/Nancy/pull/2441

This is really significant.   In Nancy V1, you specified routes using the following:

If you have a large web app with many routes and modules, although a trivial change, this could take some significant time.


I decided to try to create a new module that would add back the existing routing behavior by calling the new underlying methods in the NancyModule.  This would allow me to simply change all my existing modules to extend this new class rather than the new Module in Nancy v2.


This then adds back in all the existing routing.  Just simply extend NancyV1Module instead of NancyModule.

Upgrading Nancy

I’ve created a console application with the source available on GitHub.

Have you ran into any significant issues when upgrading Nancy to v2?  Please let me know on Twitter or in the comments.

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Roundup #16: NET Standard 2.1, Endpoint Routing, Bullseye, API Spec Workflow

Here are the things that caught my eye this week.  I’d love to hear what you found most interesting this week.  Let me know in the comments or on Twitter.

.NET Standard 2.1

This document describes the plan for .NET Standard 2.1, which includes the definition of its API surface.

We did a diff between .NET Core 2.1 and .NET Standard 2.0 to see which APIs that were added in .NET Core would be great candidates for inclusion in the standard.

Interesting to read some of the pros/cons for versioning and the decision to go with 2.1

Link: https://github.com/dotnet/standard/blob/master/docs/planning/netstandard-2.1/README.md


Endpoint Routing

We’re making a big investment in routing starting in 2.2 to make it interoperate more seamlessly with middleware. For 2.2 this will start with us making a few changes to the routing model, and adding some minor features. In 3.0 the plan is to introduce a model where routing and middleware operate together naturally. This post will focus on the 2.2 improvements, we’ll discuss 3.0 a bit further in the future.

Pretty nice to see this as I’ve been wanting this for some time now, hence blog post on generating links to routes outside of MVC.

Link: https://blogs.msdn.microsoft.com/webdev/2018/08/27/asp-net-core-2-2-0-preview1-endpoint-routing/



Bullseye is a .NET package for describing and running targets and their dependencies.

Bullseye can be used to write targets that do anything. It is not coupled to building .NET projects.

Really cool project that I just discovered by Adam Ralph.  Bullseye feels like a great and simple way to define some targets for doing tasks.  Feels very much like Cake without all the extra plugins.  Anyone using it already? Going to explore it more.

Link: https://github.com/adamralph/bullseye


Our API Specification Workflow

A year ago we started trying to figure out the best way to not just document HTTP APIs, but to leverage API specifications to avoid duplicating efforts on loads of similar-but-different tasks; maintaining Postman Collections, creating mocks, contract testing, payload validation, etc. To us, it felt like API developers were wasting a lot of time writing up the same logic over and over again. Listing endpoints, defining what fields should have what data, figuring out validation logic, writing up examples, doing this all over and over again in loads of different formats, then — the few folks that have enough time and interest —would write loads of tests to make sure all these different formats were saying the same thing.

Link: https://engineering.wework.com/our-api-specification-workflow-9337448d6ee6


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Generating links with UrlHelper outside of ASP.NET Core

UrlHelper outside of ASP.NET CoreI’ve been trying to solve the issue of generating links with UrlHelper outside of ASP.NET Core.  The problem I was facing was wanting to use UrlHelper while not directly in the context of ASP.NET Core.

There are two specific scenarios were:

  • Generate a link for an ASP.NET Core MVC route that I was going to be using in an email.  This is a separate process that is not running ASP.NET Core but does have references to the assemblies that contain the controllers.
  • Generate a link for an ASP.NET Core MVC route from a Nancy Module running in a Katana self host.  This also has a reference to the assemblies containing the asp.net controllers.


I tried various different solutions but couldn’t come up with a solution.  After a ton of searching, I finally found a StackOverflow post that provided a solution.  Although not pretty, it does work.

Here’s a sample console application.  First, there are a few extension methods for setting up the web host builder, application builder and generating the UrlHelper with a default HttpContext.

Next is to create a Startup class we will use in our web host builder.

Lastly, putting it all into place is to build a web host and then use the extension method to get a UrlHelper.  You’ll notice you need to provide the base path to the extension method.  This is because the extension method uses this base address as the request within the HttpContext it’s creating.


I’ve created a console application with the source available on GitHub.

If you know of a method of generating a link to an ASP.NET Core MVC route without being in the context of ASP.NET Core, please let me know on Twitter or in the comments.

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