如何从NSUrlSession仅返回NSHttpUrlResponse状态代码

Question

如何从NSUrlSession只返回一个NSHttpUrlResponse状态代码。我对这个language.So非常陌生，如果还有其他更好的做法，请让我know.My代码就在这里下面。

//Method to return a status code
        func responseCode() -> Int{
        var responseCode : Int=0
        if Reachability.isConnectedToNetwork() == true {
        // get news feed url
        let url = NSURL(string: baseUrl)
        let session = NSURLSession.sharedSession()
//create request
        let request = NSMutableURLRequest(URL: url!)
        request.HTTPMethod = httpMethod
//check null value
        if (bodyData != "") {
            request.HTTPBody =  bodyData.dataUsingEncoding(NSUTF8StringEncoding);
        }
        if (auth != "") {
            print("Token Auth : \(auth)")
            request.addValue("bearer \(self.auth)", forHTTPHeaderField:      "Authorization")
        }
        print("request : \(request)")

//How to return a Integer from this below function
        let task = session.dataTaskWithRequest(request,     completionHandler: {(data, response, error) -> Void in
            print("Error\(error)")
            if let httpResponse = response as? NSHTTPURLResponse {
                print("HttpReponse\(httpResponse.statusCode)")
                // Get a status code and assign it in a variable
                responseCode = httpResponse.statusCode
            }
        })
        task.resume()
//Return a response code in ViewController but it just return a initial set value that is 0
        return responseCode
        }
//Return a responseCode in ViewController but it just return a    initial set value that is 0
    return responseCode
    }

Answer 1

在这里，session.dataTaskWithRequest是一个异步任务，也就是说，它将在另一个线程(不是主线程)中被调用，当你从服务器得到响应时，它的闭包将被调用。

所以你在这里做的是试图返回responseCode，这是在主线程中调用的，也就是说，它会在你得到任何响应之前返回。

您应该使用完成处理程序：

func responseCode(completion: (statusCode:Int) -> ()){
        if Reachability.isConnectedToNetwork() == true {

            let url = NSURL(string: baseUrl)
            let session = NSURLSession.sharedSession()

            let task = session.dataTaskWithRequest(request,completionHandler: {(data, response, error) -> Void in
                print("Error\(error)")

                if let httpResponse = response as? NSHTTPURLResponse {

                    print("HttpReponse\(httpResponse.statusCode)")
                    // Get a status code and assign it in a variable
                    completion(statusCode: httpResponse.statusCode)

                }
            })
            task.resume()
        }
    }

如下所示使用此函数：

responseCode { (statusCode) -> () in
            print("Status Code:\(statusCode)")
    }