Cache rewards

Sometimes, it has to be fresh, be it bread, fish, or data.

But, sometimes, what you have got is what you need. And you don't need up-to-the-minute refreshes of data that you have already obtained. Cocoa offers much flexibility when it comes to caching request responses, and here's the easiest way to do it:

func cacheDataRequest() 
{ 
  let urlString = "http://www.grimshaw.de/Mac OS-book/test.json" 
  let url = URL(string: urlString)! 
  let request = URLRequest(url: url, 
                           cachePolicy: .returnCacheDataElseLoad, 
                           timeoutInterval: 20) 
  let session = URLSession.shared 
  let task = session.dataTask(with: request, 
                              completionHandler: 
    { 
      data, response, error in 
      do { 
           let jsonData = try JSONSerialization.
                                       jsonObject(with: data!, 
                                       options: [.allowFragments]) 
           print(jsonData) 
     ...