GitHub – stollcri/elm-init: Simple tool to quickly set up an elm application

I am trying to pass flags value to Top.elm from Main.elm
and run a function named “getToken” with flags value.
But, it seems like this function “getToken” is not working properly…

My Main.elm is …

type alias Model =
    { key : Nav.Key
    , page : Page
    }


type Page
    = NotFound
    | TopPage ( Page.Top.Model, Cmd Page.Top.Msg )
    | ArticlePage Page.Article.Model


init : String -> Url.Url -> Nav.Key -> ( Model, Cmd Msg )
init flags url key =
    Model key (TopPage (Page.Top.init flags))
        |> goTo (Route.parse url)

My Top.elm is …

type alias Model =
    { status : LoadingStatus
    }


type LoadingStatus
    = Init
    | Waiting
    | Loaded Token
    | Failed Http.Error


init : String -> ( Model, Cmd Msg )
init token =
    ( Model Init
    , getToken token )

...

-- UPDATE


type Msg
    = GotToken (Result Http.Error Token)


update : Msg -> Model -> ( Model, Cmd Msg )
update msg model =
    case msg of
        GotToken (Ok token) ->
            ( { model | status = Loaded token }, Cmd.none )

        GotToken (Err err) ->
            ( { model | status = Failed err }, Cmd.none )




-- VIEW


view : Model -> Html Msg
view model =
    case model.status of
            Init ->
                text "sssssssssssssssssssssssssssss"

            Waiting ->
                text "waiting..."

            Loaded token ->
                div []
                    [ p [] [ text "yahoooooooo" ]
                    , p [] [ text token.accessToken ]
                    ]

            Failed e ->
                case e of
                    Http.BadBody message ->
                        pre [] [ text message ]

                    _ ->
                        -- text (Debug.toString e)
                        pre [] [ text "error" ]

...

type alias Token =
    { accessToken : String
    }


-- AccessToken


getToken : String -> Cmd Msg
getToken token =
    Http.request
        { method = "POST"
        , headers =
            [ Http.header "Authorization" ("Bearer "    token)
            , Http.header "Accept" "application/json"
            , Http.header "Content-Type" "application/json"
            ]
        , url = "http://localhost:8080/web_users/create"
        , expect = Http.expectJson GotToken tokenDecoder
        , body = Http.emptyBody
        , timeout = Nothing
        , tracker = Nothing
        }


tokenDecoder : Decoder Token
tokenDecoder =
    D.map Token
        (D.field "access_token" D.string)

text “sssssssssssssssssssssssssssss” can be seen in a view after the server is launched.
So, it seems like Init in Top.elm is working.
But, it won’t go any further.

I assume that getToken function is not working here because I can only see LoadingStatus Init (not Waiting, Loaded, Failed)

Does anybody know why getToken function is not working correctly…??

No error occurs.

I see from the syntax you’re using that this is not Elm 0.16, which is the version where the record update syntax changed. In your current version of Elm you can do:

type alias Model a =
  {a | pinned : Bool, done : Bool, trunc : Bool}

init : a -> Model a -- the parentheses were superfluous so I removed them
init cont0 =
  let cont1 = { cont0 | pinned = False }
      cont2 = { cont1 | done = False }
      cont3 = { cont2 | trunc = False }
  in cont3

Since according to the type annotation, you’re adding fields, not updating fields. You can only add one field at a time, sadly, so please excuse the awkward syntax.

Note that in Elm 0.16field addition syntax has been removed. It wasn’t used very much and newcomers found the = versus <- very confusing. So the field addition was removed and the update syntax was changed to use =. This means that in a new version of Elm you won’t be able to write your init function this way anymore. See the blog post and mailing list for strategies to rewrite programs with extensible records to use other types to model things.

To give one example of how you may change your program to still work with Elm 0.16 :

type alias Model a =
  { submodel: a, pinned: Bool, done: Bool, trunc: Bool }

init : a -> Model a
init submodel = Module submodel False False False
-- This makes use of the generated record constructor
--  that came with the type alias definition.
-- You could also write: 
--  { submodel: submodel, pinned: False, done: False, trunc: False }