Question

我正在使用Suave构建经过身份验证的Web API，我经常偶然发现在不同功能中聚合信息的问题

pathScan Navigation.playersAvailables GetGame >>= getInSession >>= (fun (gameId,playerInSession) -> //access to both gameId and player in session)

签名：

getGame : HttpContext -> Async<HttpContext option>
getInSession : HttpContext -> Async<HttpContext option>

getGame从httpContext.request.querystring getInSession
从httpContext.cookie

为了做到这一点，我发现的唯一一件事就是在userDataDictionnary中存储信息：

Writers.setUserData "player"  { playerId= playersId; socialId=socialId; username = username}

要在另一个函数中检索它，但它对我来说看起来很讨厌：

let player = x.userState.["player"] :?> PlayerSession
//do some other stuff now that we have the current player

还有另一种方法吗？我想拥有像这样的纯粹功能 getGameId并获取Session等等。并且能够组合它们，因为我希望处理我的不同路线：

pathScan Navigation.playersAvailables GetGame >>= getInSession >>= (fun (gameId,playerInSession) -> //access to both gameId and player in session)
pathScan Navigation.otherRoute GetGame >>= (fun (gameId) -> //process gameId)
pathScan Navigation.otherRoute2 getInSession >>= (fun (sessionId) -> //process sessionId to do some other stuff)

我担心我需要的是与一些真正的函数程序员进行一天的交谈..

Answer 1

setUserData是一个纯函数-src。

不确定this是否仍然是最新的，但是它表示pathScan和>>=不能很好地链接。不过，我认为您使用的Writers.setUserData可能可以完成它。

使用提包将东西拉出来不是很可爱。

怎么样：

let (|ParseInt|_|) =
    function
    | "" | null -> None
    | x ->
        match Int32.TryParse x with
        | true, i -> Some i
        | _ -> None


let (|HasParam|_|) name (ctx:HttpContext) =
    ctx.request.queryParam name
    |> function
        |Choice1Of2 value ->
            Some value
        | _ -> None

let playersAvailablePart:WebPart =
    function
    //access to both gameId and player in session
    |HasParam "inSession" playerInSession & HasParam "gameId" gameId as ctx ->
        // do your processing here, sample return:
        OK "we had all the required important parts" ctx
    // or an example of something more strongly typed
    | HasParam "inSession" (ParseInt playerInSession) & HasParam "gameId" (ParseInt gameId) as ctx ->
        // do your processing here, sample return:
        OK "we had all the required important parts" ctx
    | ctx -> never ctx

如果值不在queryParameters中，这将无法正常工作，但是您可以将其调整为适合它们的位置

在Suave

1 个答案: