嵌套Suave Web部件

我试图实现的是实现一个简单的Rest API:

• 用户可以获得有关金融工具的信息
• 此外,每种仪器都有一份价格清单

现在为了简单起见,我只关注GET方法。

我的 非常 基本代码如下:

[<AutoOpen>]
module RestFul =    

    let JSON v =     
        let jsonSerializerSettings = new JsonSerializerSettings()
        jsonSerializerSettings.ContractResolver <- new CamelCasePropertyNamesContractResolver()

        JsonConvert.SerializeObject(v, jsonSerializerSettings)
        |> OK 
        >=> Writers.setMimeType "application/json; charset=utf-8"

    let fromJson<'a> json =
        JsonConvert.DeserializeObject(json, typeof<'a>) :?> 'a    

    let getResourceFromReq<'a> (req : HttpRequest) = 
        let getString rawForm = System.Text.Encoding.UTF8.GetString(rawForm)
        req.rawForm |> getString |> fromJson<'a>

    type RestResource<'a> = {
        GetById : int -> 'a option
        GetPricesById : int -> 'a option
    }

    let rest resource =

        let handleResource requestError = function
            | Some r -> r |> JSON
            | _ -> requestError

        let getResourceById = 
            resource.GetById >> handleResource (NOT_FOUND "Resource not found")

        let getPricesById = 
            resource.GetPricesById >> handleResource (NOT_FOUND "Resource not found")

        choose [
            GET >=> pathScan "/instrument/%d" getResourceById
            GET >=> pathScan "/instrument/%d/prices" getPricesById
        ]


module Main =
    [<EntryPoint>]
    let main argv = 

        let webPart = rest {
                GetById = fun i -> Some i // placeholder
                GetPricesById = fun i -> Some i // placeholder, it'll be a list eventually
            }

        startWebServer defaultConfig webPart
        0

当我这样定义Web部件时:

choose [
    GET >=> pathScan "/instrument/%d" getResourceById // Returns the instrument static data
    GET >=> pathScan "/instrument/%d/prices" getPricesById // Returns price list for the instrument
]

// My idea about the code - doesn't compile
choose [
    pathScan "/instrument/%d" getResourceById >=> choose [
        GET // Returns the instrument static data
        GET >=> path "/prices" >=> (somehow refer to the previous id and get prices)  // Returns price list for the instrument
    ]
]