Question

我试图在榆树中执行GET请求。该函数返回我正在尝试执行的任务。不幸的是，我的参考资料是Elm 0.17，我收集的是Task.perform的签名已经改变。

fetchTasks: MyModel -> String -> Platform.Task Http.Error (Dict String MyTask)
fetchTasks model apiUrl=
    { method          = "GET"
    , headers         = [ Http.header "Content-Type"  "application/json"
                        , Http.header "Authorization" model.token ]
    , url             = apiUrl
    , body            = Http.emptyBody
    , expect          = Http.expectJson (dict taskDecoder)
    , timeout         = Nothing
    , withCredentials = False    }
    |> Http.request
    |> Http.toTask



fetchTaskCmd : MyModel -> String -> Cmd Msg
fetchTaskCmd model apiUrl =
    Task.perform AuthError GetTasksSuccess <| fetchTasks model apiUrl

这是我的GET请求函数和执行任务的命令。 AuthError和GetTasksSuccess都是我定义的Messaging。我在Elm Docs中读到的任务执行的新签名是

perform : (a -> msg) -> Task Never a -> Cmd msg

我需要做些什么来实现我的命令？

Answer 1

更改比您建议的更大，Http库现在主要使用命令，而不是任务。所以现在写它的方法是：

makeRequest model apiUrl=
  Http.request
    { method          = "GET"
    , headers         = [ Http.header "Content-Type"  "application/json"
                        , Http.header "Authorization" model.token ]
    , url             = apiUrl
    , body            = Http.emptyBody
    , expect          = Http.expectJson (dict taskDecoder)
    , timeout         = Nothing
    , withCredentials = False    }




fetchTaskCmd : (Result Error a -> Msg) -> MyModel -> String -> Cmd Msg
fetchTaskCmd msgConstructor model apiUrl =
    Http.send msgConstructor (makeRequest model apiUrl)

如果您想使用令牌，您可能还需要考虑使用我的elm-jwt库来提供帮助。

榆树0.18 Http请求

1 个答案: