Task requests and tracking progress

[Janiczek]

Is there a reason Task requests don't accept the tracker field to track progress?

https://package.elm-lang.org/packages/elm/http/latest/Http#task
compare to
https://package.elm-lang.org/packages/elm/http/latest/Http#request

[jaredramirez]

Maybe relevant: https://discourse.elm-lang.org/t/upload-files-to-s3/4314/14?u=jaredramirez

[lydell]

Here’s a use case.

I made a function that first asks my API for an AWS S3 signed URL, and then uploads a file to that signed URL (using Task.andThen). Now I wanted to show the upload progress, but learned that Http.task does not take a tracker. It felt nice having a function that let me upload a file without having to think about the presigned URL, but now I have to break it up into two steps and use Http.request instead.

[toastal]

Use case 2:

I wanted a waitAtLeast function for my form submissions because sometimes that request would react before the user knew, additionally sometimes I raise a toast on the screen and don't want it to popup and disappear too quickly if the request is fast. If Cmd/Tasks were like Futures, I'd run a timer and the request in parallel and await both the results (ditching the timer) Parallelism isn't really supported in that sort of way. To get around that, I've used Task.andThen like:

waitAtLeast : Int -> Task x a -> Task x a
waitAtLeast delay task =
    -- Sure would be nice to have do notation here
    -- do
    --   start <- Time.now
    --   value <- task
    --   end <- Time.now
    --   let toWait = end - start - delay
    -- . . .
    -- desugared into:
    Time.now
        |> Task.andThen
            (\start ->
                task
                    |> Task.andThen
                        (\value ->
                            Time.now
                                |> Task.andThen
                                    (\end ->
                                        let
                                            toWait : Int
                                            toWait =
                                                delay
                                                    - Time.posixToMillis end
                                                    + Time.posixToMillis start
                                        in
                                        if toWait <= 0 then
                                            Task.succeed value

                                        else
                                            Process.sleep (toFloat toWait)
                                                |> Task.andThen (\_ -> Task.succeed value)
                                    )
                        )
            )

Turning a Http.Request into a Task, I get the waitAtLeast part I wanted, but now that it's a Task I have no access to the tracker.

[jjant]

@evancz ?