How to make http request and decode response to concrete type in Elm 0.17?

Question

I want to create a function that will make a request to the server and returns decoded value. I have custom headers within my request so I have to use Http.send function.

So far I was able to create task

getCurrentUser userId authToken err ok =
  let
    request =
      Http.send defaultSettings
        { verb = "GET"
        , headers = [("X-Auth", authToken)]
        , url = "http://os.apiary.com"
        , body = empty
        }

  in
    Task.perform err ok request

type alias User = { name : String, age : Maybe Int }
userDecoder = object2 User ("name" := string) (maybe ("age" := int))

but I don't know where to put decode logic.

Answer 1

I think you're looking for fromJson:

getCurrentUser userId authToken err ok =
  let
    request =
      Http.send defaultSettings
        { verb = "GET"
        , headers = [("X-Auth", authToken)]
        , url = "http://os.apiary.com"
        , body = empty
        }

  in
    Http.fromJson userDecoder request
      |> Task.perform err ok