F＃异步HTTP请求 - 解析JSON响应

Question

我试图使用F#下面的代码片断发送异步POST请求火力地堡：特别是下列的操作，这允许匿名登录：

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 
    } 

我打电话，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#，有点搞不清关于这是如何工作的。我如何从这个请求中获得JSON响应？我如何知道何时完成？这会阻止主线程上的UI吗？我做的是翻译的斯威夫特以下代码块：

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

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

    }) 

这里的一切对我来说很有意义，因为我们有一个完成块的方法执行完毕后调用的，而且我们知道，user变量包含从服务器获得的响应，这在F＃中对我来说意义不大。

UPDATE：

继在意见的建议，我已引用F＃数据：HTTP实用程序，并创建了下面的代码片段：

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，这会产生错误The value, namespace, type or module Http is not defined

UPDATE 2： 我已经解决了以下代码：

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 

以下这里的例子：

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

但是当我打电话openLandlord功能在这里：

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

我收到以下错误：

这种表达预计有型但是这里有字符串。

错误：

1. 在或结合在此点之前的不完全的结构化构建体。
2. 未定义构造函数请求的值。
3. 成员定义中的意外关键字匹配。
4. 未定义值，名称空间，类型或模块响应。
5. 成员定义中意外标识。

Answer 1

检查下面的代码：

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 

如果类型提供不与您的设置工作，这可能会帮助：https://github.com/Microsoft/visualfsharp/issues/3303

更换样品JSON什么是从服务的预期。