Swift - 向下转换NSURLResponse到NSHTTPURLResponse以获取响应代码 [英] Swift - downcast NSURLResponse to NSHTTPURLResponse in order to get response code

问题描述

我正在使用NSURLRequest在SWIFT中构建休息查询

  var request：NSURLRequest = NSURLRequest（URL：url）
 
 var connection：NSURLConnection = NSURLConnection（请求：request，delegate：self，startImmediately：false）！ 
 connection.start（）
  

我的问题是如何获取响应代码返回的响应：

  func connection（didReceiveResponse：NSURLConnection！，didReceiveResponse response：NSURLResponse！）{
 / / ... 
} 
  

根据Apple的说法： NSHTTPURLResponse 这是 NSURLResponse的子类有一个状态代码，但我不知道如何转发我的响应对象，以便我可以看到响应代码。 / p>

这似乎没有削减它：

  println（（ NSHTTPURLResponse）response.statusCode）
  

谢谢

解决方案

使用可选的强制转换（ as？）和可选绑定（如果让）：

  func connection（didReceiveResponse：NSURLConnection！，didReceiveResponse response：NSURLResponse！）{
 if let httpResponse = respon作为？ NSHTTPURLResponse {
 println（httpResponse.statusCode）
} else {
 assertionFailure（意外回复）
} 
} 
  

或作为单行

 让statusCode =（响应为？NSHTTPURLResponse）?. statusCode ?? -1 
  

其中状态代码将设置为 -1 如果响应不是HTTP响应
（对于HTTP请求不应该发生）。

I'm building rest queries in SWIFT using NSURLRequest

var request : NSURLRequest = NSURLRequest(URL: url)

var connection : NSURLConnection = NSURLConnection(request: request, delegate: self, startImmediately: false)!
connection.start()

My question is how to do i get response code out of the response that is returned:

    func connection(didReceiveResponse: NSURLConnection!, didReceiveResponse response: NSURLResponse!) {
//...
}

According to Apple: NSHTTPURLResponse which is a subclass of NSURLResponse has a status code but I'm not sure how to downcast my response object so i can see the response code.

This doesn't seem to cut it:

println((NSHTTPURLResponse)response.statusCode)

Thanks

解决方案

Use an optional cast (as?) with optional binding (if let):

func connection(didReceiveResponse: NSURLConnection!, didReceiveResponse response: NSURLResponse!) {
    if let httpResponse = response as? NSHTTPURLResponse {
        println(httpResponse.statusCode)
    } else {
        assertionFailure("unexpected response")
    }
}

or as a one-liner

let statusCode = (response as? NSHTTPURLResponse)?.statusCode ?? -1

where the status code would be set to -1 if the response is not an HTTP response (which should not happen for an HTTP request).

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