Swift 3 - 发送同步 http 请求 [英] Swift 3 - Send make synchronous http request

问题描述

我有以下代码:

func completeLoadAction(urlString:String) -> Int {
    let url = URL(string:urlString.trimmingCharacters(in: .whitespaces))
    let request = URLRequest(url: url!)
    let task = URLSession.shared.dataTask(with: request) { data, response, error in
        guard let data = data, error == nil else {                                                 // check for fundamental networking error
            print("error=(error)")
            let ac = UIAlertController(title: "Unable to complete", message: "The load has been added to the completion queue. This will be processed once there is a connection.", preferredStyle: .alert)
            ac.addAction(UIAlertAction(title: "OK", style: .default))
            self.present(ac, animated:  true)
            return
        }

    let httpStatus = response as? HTTPURLResponse
        var httpStatusCode:Int = (httpStatus?.statusCode)!

        let responseString = String(data: data, encoding: .utf8)
        print("responseString = (responseString)")
        let ac = UIAlertController(title: "Completed Successfully", message: "The "+coldel+" has been completed successfully", preferredStyle: .alert)
        ac.addAction(UIAlertAction(title:"Continue", style: .default, handler:  { action in self.performSegue(withIdentifier: "segueConfirmedLoad", sender: self) }))

        self.present(ac, animated: true)

    }
    task.resume()
    return httpStatusCode
}

我需要能够调用它，同时检查返回值，因为它是http状态码，它会让我知道调用是否成功.

I need to be able to call this and at the same time check the return value as it is the http status code, it will let me know if the call was successful or not.

问题是因为它在 dataTask 中，我无法在此处访问响应状态代码

Problem is because it's in a dataTask I can't access the responses status code here

var httpStatusCode:Int = (httpStatus?.statusCode)!

因为在调用 Task.Resume() 之前任务不会启动，并且任务是异步的，所以它永远不会工作.

Because the task doesn't start until Task.Resume() is called and the task is asynchronous so it will never work.

有什么办法可以解决这个问题吗?

Are there any ways around this?

推荐答案

总有一种方法可以使用异步模式.

There is always a way to use the asynchronous pattern.

为了使函数异步添加一个完成块

To make the function asynchronous add a completion block

func completeLoadAction(urlString:String, completion: (Int) -> ()) {
   let url = URL(string:urlString.trimmingCharacters(in: .whitespaces))
   let request = URLRequest(url: url!)
   let task = URLSession.shared.dataTask(with: request) { data, response, error in
      guard let data = data, error == nil else {                                                 // check for fundamental networking error
         print("error=(error)")
         DispatchQueue.main.async {
            let ac = UIAlertController(title: "Unable to complete", message: "The load has been added to the completion queue. This will be processed once there is a connection.", preferredStyle: .alert)
            ac.addAction(UIAlertAction(title: "OK", style: .default))
            self.present(ac, animated:  true)
         }
         completion(0) // or return an error code 
         return     
      }

      let httpStatus = response as? HTTPURLResponse
      var httpStatusCode:Int = (httpStatus?.statusCode)!

      let responseString = String(data: data, encoding: .utf8)
      print("responseString = (responseString)")
      DispatchQueue.main.async {
         let ac = UIAlertController(title: "Completed Successfully", message: "The "+coldel+" has been completed successfully", preferredStyle: .alert)
         ac.addAction(UIAlertAction(title:"Continue", style: .default, handler:  { action in self.performSegue(withIdentifier: "segueConfirmedLoad", sender: self) }))
         self.present(ac, animated: true)
      }
      completion(httpStatusCode)
   }
   task.resume()

}

并这样称呼它

completeLoadAction(urlString: "www.something.com") { code in
   print(code)
}

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