为了方便使用，我写了下面的代码，它运作正常。

For easy use I wrote below code and It's working perfectly.

var video_Url = ""
    if let url  = NSURL(string: Response),
    data = NSData(contentsOfURL: url)
    {
        video_Url = Response
    }
    else
    {
        video_Url = ""
    }