HTTP Lens for interfacing with an API?

Question

I'm just starting to pick up momentum with Haskell, and loving the abstractions I run into daily, such as lens.

I'm to a point where a REST API lens would be useful to work with, but before I spend hours finding it's not possible... is it?

The major problem I see is that I'm not directly accessing a data structure, but outputting a string which is requested (my lens syntax is probably wrong):

λ> over (user "robertplant") . set favoritesong

POST http://...com/api/user/robertplant/favoritesong
{
  ...
}

----

λ> over (user "robertplant") . view _1

GET http://...com/api/user/robertplant/favoritesong/123

I'm assuming that's at least an Applicative problem, or possibly needs an Monad?

I mean, I could imagine this lens satisfying the lens laws (in some sense... it's still a bit fuzzy to me), but I haven't seen yet that a lens has the hardware for putting out strings/other data structures like this.

Is this a journey worth pursuing?

glguy glguy · Accepted Answer · 2017-02-25T06:51:22

No, this doesn't have anything to do with lenses, unfortunately. Lenses are things that satisfy the lens laws

view l (set l v s) ≡ v
set l (view l s) s ≡ s
set l v' (set l v s) ≡ set l v' s

It's possible there's some clever thing you would write in Haskell to produce the outputs you're looking for, it just won't be related to this topic.

HTTP Lens for interfacing with an API?

1 Answers