从Suave请求中聚合信息

Question

我正在使用Suave构建一个经过身份验证的web API，而且我经常遇到通过不同功能聚合信息的问题。

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获取id
• 从sessionId到httpContext.cookie

为了做到这一点，我发现的唯一方法就是在userDataDictionnary中存储信息：

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

并在另一个函数中检索它，但在我看来，它非常讨厌：

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

还有别的办法吗？我想拥有像getGameId和get会话之类的纯函数。当我想要处理我的不同路线时，我能写出它们：

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)

恐怕我需要的是和一个真正的功能程序员谈一天。

Answer 1

setUserData是一个纯函数-- src。

不确定这是否仍然是当前的，但它说pathScan和>>=不能很好地链接在一起。然而，我认为您正在使用的Writers.setUserData可能能够完成它。

拿着一个物品袋把东西拿出来不是很好。

不如：

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

如果这些值不在queryParameters中，则这并不完全有效，但您可以将其调整到它们所在的位置