iOS 解析短链接

let urlString = "" // 短链接地址let configuration = NSURLSessionConfiguration.defaultSessionConfiguration()/* Tip：为了安全，最好设置下 User-Agentlet xHTTPAdditionalHeaders: [NSObject: AnyObject] = ["User-Agent": UserAgent.userAgentString]                     configuration.HTTPAdditionalHeaders = xHTTPAdditionalHeaders*/ let session = NSURLSession(configuration: configuration)let task = session.dataTaskWithRequest(NSURLRequest(URL: scanString.urlValue!), completionHandler: { (data, response, error) in    print("短链接解析 error ：\(error)")                    dispatch_async(dispatch_get_main_queue(), {        if error == nil {            if let str = response?.URL?.absoluteString { // 解析后的长链接                // 成功操作            } else {                // 失败操作            }        } else {            // 失败操作        }