iOS检测网络是否挂了代理(swift版)

        let dic = CFNetworkCopySystemProxySettings()!.takeUnretainedValue()
        let arr = CFNetworkCopyProxiesForURL(URL(string: "https://www.baidu.com")! as CFURL, dic).takeUnretainedValue()
        
        let obj = (arr as [AnyObject])[0]
        
        let host = obj.object(forKey: kCFProxyHostNameKey) ?? "null"
        let port = obj.object(forKey: kCFProxyPortNumberKey) ?? "null"
        let type = obj.object(forKey: kCFProxyTypeKey) ?? "null"
        
        print(host)
        print(port)
        print(type)
        
        if obj.object(forKey: kCFProxyTypeKey) == kCFProxyTypeNone {
            print("没有设置代理")
            let alert = UIAlertController(title: "代理检测", message: "没有设置代理", preferredStyle: .alert)
            present(alert, animated: true, completion: nil)
        }else {
            print("设置代理了")
            let alert = UIAlertController(title: "代理检测", message: "设置代理了\n\(host)\n\(port)\n\(type)", preferredStyle: .alert)
            present(alert, animated: true, completion: nil)
        }