带有空体的 Http DELETE

Question

在 Elm (0.18) 中，我正在调用一个 http DELETE 端点，如果成功则以 200 和一个空主体进行响应。

在这种情况下（成功），我需要用初始 id ( OnDelete playerId ) 传回一条消息。 但是由于身体是空的，我无法从那里解析它。

目前我正在这样做，但是有没有更优雅的方式来编写Http.Request的expect部分：

Http.expectStringResponse (\response -> Ok playerId)

?

这反映了我当前的代码：

deletePlayer : PlayerId -> Cmd Msg
deletePlayer playerId =
    deleteRequest playerId
        |> Http.send OnDelete


deleteRequest : PlayerId -> Http.Request PlayerId
deleteRequest playerId =
    Http.request
        { body = Http.emptyBody

        , expect = Http.expectStringResponse (\response -> Ok playerId)

        , headers = []
        , method = "DELETE"
        , timeout = Nothing
        , url = "http://someHost/players/" ++ playerId
        , withCredentials = False
        }


type alias PlayerId =
    String

Answer 1

Elm v0.19 添加了expectWhatever 。 它的行为与检查错误的Result略有不同，但效果相似。

---

我为“空”200 个响应创建了一个助手expectUnit 。

expectUnit : Expect ()
expectUnit =
    Http.expectStringResponse << always <| Ok ()



deleteThing : String -> Request ()
deleteThing path =
    Http.request
        { method = "DELETE"
        , headers = []
        , url = "http://localhost/api"
        , body = Http.jsonBody <| Encode.object [ ( "path", Encode.string path ) ]
        , expect = expectUnit
        , timeout = Nothing
        , withCredentials = False
        }

但对你来说，你能得到的最好的就是。

{ ...
, expect = Http.expectStringResponse << always <| Ok playerId
...
}

或者您可以创建一个助手（实际上是Expect的singleton或pure ）

alwaysExpect : a -> Expect a
alwaysExpect =
     Http.expectStringResponse << always << Ok

可以像这样使用

{ ...
, expect = alwaysExpect playerId
...
}