Swift 3：URLSession / URLRequest不起作用
我仍然试图将我们的应用程序从Swift 2转换为Swift 3，因为我被迫，因为我们所有的Apple设备现在都在运行iOS 10。
我已经完成了代码转换，并认为我做得很好，但是在尝试调试我的JSON问题时（在另一个问题中发布），我现在处理的请求甚至没有被发送。
let params: [String:AnyObject] = [ "email":"\(self.preferences.string(forKey: "preference_email")!)" as AnyObject ] let requestParams: [String:AnyObject] = [ "action":"601" as AnyObject, "params":params as AnyObject ] do { let requestObject = try JSONSerialization.data(withJSONObject: requestParams, options:[]) var request = URLRequest(url: URL(string: "http://domain.tld/path/")!) request.httpBody = requestObject request.httpMethod = "POST" let config = URLSessionConfiguration.default let session = URLSession(configuration: config) NSLog("Got here?") session.dataTask(with: request) {data, response, error in guard let data = data, error == nil else { print("error=\(error)") return } NSLog("Got here 3?") let object:JSON = JSON(data:data) NSLog("Object: \(object)") }.resume() NSLog("Got here 4?") } catch { NSLog("Got here catch?") } NSLog("End of getUser") 上面的代码产生以下输出：
2016-10-04 13:00:12.011969 OneTouch[1589:623015] [DYMTLInitPlatform] platform initialization successful 2016-10-04 13:00:12.264319 OneTouch[1589:622954] [MC] System group container for systemgroup.com.apple.configurationprofiles path is /private/var/containers/Shared/SystemGroup/systemgroup.com.apple.configurationprofiles 2016-10-04 13:00:12.265321 OneTouch[1589:622954] [MC] Reading from public effective user settings. 2016-10-04 13:00:12.295055 OneTouch[1589:622954] Got here? 2016-10-04 13:00:12.295445 OneTouch[1589:622954] Got here 4? 2016-10-04 13:00:12.295515 OneTouch[1589:622954] End of getUser (lldb)
这意味着甚至没有提出请求。 是否有一些关键我必须再次添加到PLIST？ 这开始变得烦人。
下面是我的旧代码，它甚至不再工作：
let params: [String:AnyObject] = [ "email":"\(self.preferences.string(forKey: "preference_email")!)" as AnyObject ] let requestParams: [String:AnyObject] = [ "action":"601" as AnyObject, "params":params as AnyObject ] do { let requestObject = try JSONSerialization.data(withJSONObject: requestParams, options:[]) let request = NSMutableURLRequest(url: URL(string: "http://domain.tld/path/" as String)!, cachePolicy:NSURLRequest.CachePolicy.reloadIgnoringLocalCacheData, timeoutInterval: 20) request.httpBody = requestObject request.httpMethod = "POST" NSLog("Got here?") let task = URLSession.shared.dataTask(with: request as URLRequest, completionHandler: {data, response, error in if error != nil { NSLog("Got here 2?") } NSLog("Got here 3?") let object:JSON = JSON(data:data!) NSLog("Object: \(object)") }) NSLog("Got here 4?") task.resume() } catch { NSLog("Got here catch?") } NSLog("End of getUser")
上面的代码产生与其他代码相同的输出！
如果在调用getUser之后立即放置断点，则URLSession任务的完成处理程序（异步运行（通常稍后完成，除非请求立即失败或被某些缓存响应满足））可能没有机会被调用。
如果在dataTask完成处理程序中放置断点，则应该在该点看到您的数据。
就个人而言，我确保为getUser一个完成处理程序，以便您知道它何时完成：
func getUser(completionHandler: @escaping (JSON?, Error?) -> Void) { let params = [ "email":"\(preferences.string(forKey: "preference_email")!)" ] let requestParams: [String: Any] = [ "action": "601", "params": params ] do { let requestObject = try JSONSerialization.data(withJSONObject: requestParams) var request = URLRequest(url: URL(string: "http://domain.tld/path/")!, cachePolicy: .reloadIgnoringLocalCacheData, timeoutInterval: 20) request.httpBody = requestObject request.httpMethod = "POST" request.setValue("application/json", forHTTPHeaderField: "Content-Type") request.setValue("application/json", forHTTPHeaderField: "Accept") let task = URLSession.shared.dataTask(with: request) {data, response, error in guard let data = data, error == nil else { completionHandler(nil, error) return } completionHandler(JSON(data: data), nil) } task.resume() } catch { completionHandler(nil, error) } }
然后当你调用它时，你可以做类似的事情：
getUser { json, error in guard let json = json else { print(error) return } // do something with json print(json) }
然后将断点放在getUser的完成处理程序中。 请记住，您无法保证完成处理程序将在主队列上运行，因此您需要确保将更新和UI或模型更新发送回主队列。