Swift iOS : 访问 https 服务器

使用URLSession可以访问https服务器。为了测试方便，省下自己编写https服务器的麻烦，可以使用一个网络服务叫做httpbin.org/ip,当访问子URL时，它会返回一个json，格式为：

{
    origin = "221.237.156.243";
}

访问https代码如下：

import UIKit
@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate,URLSessionDelegate {
    var window: UIWindow?
    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
        foo()
        return true
    }
    func foo(){
        let task = URLSession.shared.dataTask(with: URL(string: "https://httpbin.org/ip")!) { (data, response, error) in
            if error != nil {
                print(error)
            } else {
                if let usableData = data {
                    do {
                        let json = try JSONSerialization.jsonObject(with: usableData, options:[])
                        print("json: \(json)")
                    }
                    catch {
                        print("Error: \(error)")
                    }
                }
            }
        }
        task.resume()
    }
}