Handling dependencies in a F# Giraffe application

Isn't handling dependencies a solved problem?

The main programming paradigm i C# is dependency injection. So one of the questions I frequently encounter when discussing F# is "How do you do dependency injection in F#?"

The easy answer to that is "The same way as you would do in C#". You create MVC and Minimal API apps using F# the same way as you would in C#. Register your services during startup, and create a class for your controller with the required dependencies as constructor parameters. Or create a minimal API definition using the [<FromServices>]-attribute like in C#.

But that is just a part of the answer. Giraffe is my go-to framework for building web apps using F#, and it offers no definitive solution out of the box for handling dependencies.

3 ways of doing dependency handling using Giraffe

• Baseline: No dependency injection
• Getting dependencies from HttpContext
• Injecting dependencies to WebApp
• Injecting functions as record to WebApp