F＃異步HTTP請求 - 解析JSON響應

Question

我試圖使用F#下面的代碼片斷髮送異步POST請求火力地堡：特別是下列的操作，這允許匿名登錄：

https://firebase.google.com/docs/reference/rest/auth/#section-sign-in-anonymously

let makePostRequest (url : string) (requestBody : string) = 
    let req = WebRequest.CreateHttp url 
    req.CookieContainer <- new CookieContainer() 
    req.Method <- "POST" 
    req.ProtocolVersion <- HttpVersion.Version10 
    let postBytes = requestBody |> System.Text.Encoding.ASCII.GetBytes 
    req.ContentLength <- postBytes.LongLength 
    req.ContentType <- "application/xml; charset=utf-8" 
    async{ 
     use! reqStream = req.GetRequestStreamAsync() |> Async.AwaitTask 
     do! reqStream.WriteAsync(postBytes, 0, postBytes.Length) |> Async.AwaitIAsyncResult |> Async.Ignore 
     reqStream.Close() 
     use! res = req.AsyncGetResponse() 
     use stream = res.GetResponseStream() 
     use reader = new StreamReader(stream) 
     let! rdata = reader.ReadToEndAsync() |> Async.AwaitTask   
     return rdata 
    } 

我打電話，如下所示：

let url = "https://www.googleapis.com/identitytoolkit/v3/relyingparty/signupNewUser?key=XXXXXXXXXXXXXXXXX" 
    let data = "returnSecureToken=true" 
    makePostRequest url data 

我很新的F#，有點搞不清關於這是如何工作的。我如何從這個請求中獲得JSON響應？我如何知道何時完成？這會阻止主線程上的UI嗎？我做的是翻譯的斯威夫特以下代碼塊：

Auth.auth().signInAnonymously(completion: { (user, error) in 

     if let err = error { 
      print(err.localizedDescription) 
      return 
     } 

    }) 

這裏的一切對我來說很有意義，因爲我們有一個完成塊的方法執行完畢後調用的，而且我們知道，user變量包含從服務器獲得的響應，這在F＃中對我來說意義不大。

UPDATE：

繼在意見的建議，我已引用F＃數據：HTTP實用程序，並創建了下面的代碼片段：

let url = "https://www.googleapis.com/identitytoolkit/v3/relyingparty/signupNewUser?key=XXXXXXXXXXXX" 
Http.RequestString 
    (url, 
     headers = [ ContentType HttpContentTypes.Json ], 
     body = TextRequest """ {"returnSecureToken": true} """) 

然而，這會產生錯誤The value, namespace, type or module Http is not defined

UPDATE 2： 我已經解決了以下代碼：

let fetchUrl callback url (requestBody : string) =   
    let req = WebRequest.Create(Uri(url)) 
    req.Method <- "POST" 
    let postBytes = requestBody |> System.Text.Encoding.ASCII.GetBytes 
    req.ContentLength <- postBytes.LongLength 
    req.ContentType <- "application/json; charset=utf-8" 
    let reqStream = req.GetRequestStream() 
    reqStream.Write(postBytes, 0, postBytes.Length); 
    reqStream.Close() 

    use resp = req.GetResponse() 
    use stream = resp.GetResponseStream() 
    use reader = new IO.StreamReader(stream) 
    callback reader url 

let myCallback (reader:IO.StreamReader) url = 
    let html = reader.ReadToEnd() 
    let html1000 = html.Substring(0,1000) 
    printfn "Downloaded %s. First 1000 is %s" url html1000 
    html  // return all the html 


let openLandlord() = 
    let url = "https://www.googleapis.com/identitytoolkit/v3/relyingparty/signupNewUser?key=XXXXXXXXXXXXXXXXXXX" 
    let requestBody = """ {"returnSecureToken": true} """ 
    fetchUrl myCallback url requestBody 

以下這裏的例子：

https://fsharpforfunandprofit.com/posts/fvsc-download/

但是當我打電話openLandlord功能在這裏：

override x.ViewDidLoad() = 
    base.ViewDidLoad() 
    openLandlord() 

我收到以下錯誤：

這種表達預計有型但是這裏有字符串。

錯誤：

1. 在或結合在此點之前的不完全的結構化構建體。
2. 未定義構造函數請求的值。
3. 成員定義中的意外關鍵字匹配。
4. 未定義值，名稱空間，類型或模塊響應。
5. 成員定義中意外標識。

Answer 1

檢查下面的代碼：

open System 
open System.Net 
open FSharp.Data 

type Response = JsonProvider<""" { "name":"John", "age":94 } """> 

[<EntryPoint>] 
let main argv = 
    let request() = 
    async { 
     let url = "https://www.googleapis.com/identitytoolkit/v3/relyingparty/signupNewUser?key=XXXXXXXXXXXX" 
     return! Http.AsyncRequestString 
     (url, 
      headers = [ "Content-Type", HttpContentTypes.Json ], 
      body = TextRequest """ {"returnSecureToken": true} """) 
    } |> Async.Catch 
    let result = request() 
       |> Async.RunSynchronously 
    match result with 
    | Choice1Of2 text -> let json = Response.Parse text 
         printfn "name: %A" json.Name 
    | Choice2Of2 e -> printfn "request failed: %A" e 
    0 // return an integer exit code 

如果類型提供不與您的設置工作，這可能會幫助：https://github.com/Microsoft/visualfsharp/issues/3303

更換樣品JSON什麼是從服務的預期。