Actually Using the Database
Chris Wilson‘s and my mission for Bendyworks was ostensibly simple: build a secure database-backed API server in Haskell. We didn’t expect to be treading new-ish ground. When we began architecting, we could’ve started from numerous burgeoning and maturing Haskell web frameworks such as Snap or Yesod, but these would’ve been prefabricated overkill for our purposes. Instead, we decided to tread away and see where we arrived.
Free from the shackles of any particular web framework, we could leverage each framework’s best architecture decisions (such as MVC or REST) while eschewing those we found overly-constraining. We started with a single notion: model the domain logic at the type level. This meant our domain should be immediately perceptible from our database constraints and Haskell type signatures alone. What surprised us is how much Haskell we wouldn’t end up writing.
Before we get into that, though, let’s look at how some well-known server frameworks such as Rails handle their database layer.
