Saturday, January 11, 2014

Simple.Web F# Project Template Updates

F# Runtime Update

Thanks, again, to Dan Mohl for sharing some changes made to the ASP.NET MVC/WebAPI templates that I was able to apply to the Simple.Web F# project template. I had been digging into the template to figure out how to get allow changing the target F# runtime when you use the template to create a project but was unsuccessful. Fortunately, part of what Dan shared was a way to fix this-which I don't think I would have been able to figure out on my own. So, that's the first change made to the template.

Changes for Simple.Web Handlers

When I first started working with Simple.Web and tried using it with F# I ran into issues that made me have to build my handlers like so:

type Index() as this =
    member __.Get() = Status 200

    interface IGet with
        member __.Get() = this.Get()

I wasn't too happy about having to have so much duplication and double dispatch back to a handler's own methods, but most everything else worked out nicely that I just kind of accepted it, got used to it, and moved on. Once I had my first pull request into the main repository, Ryan Riley had commented on the pull request and asked why I was doing this. I'm glad he asked because I didn't even think about it. Luckily, I ran a little test and was able to pull out the extra method call!

type Index() = // No more aliasing required
    interface IGet with
        member __.Get() = Status 200

That cuts the lines of code, and complexity, in half, which is a huge win for F#. Again, it is nice to have another set of eyes out there actively looking at my work to help make it better.

Changes for Simple.Web NuGet Packages

One of the things I wanted to fix in this template was the fact that a C# file was automatically inserted into the project. This was due to the fact that I took a dependency on the Simple.Web.AspNet package. Fortunately, all this package does is reference Fix and Fix.AspNet. Since I have those packages available, I was able to safely remove the Simple.Web.AspNet package and just reference the other two directly. No more C# file to delete!

Update: Just to be a bit more clear about the Simple.Web.AspNet C# file, it was the OwinSetup file that usually goes with the C# project. The F# version has been with the F# Simple.Web template from the start.

Thanks so much to everybody who has downloaded, used, and provided feedback on this template.