title: How to stream a video with AVURLAsset and save to disk the cached data
body: <p>Some days ago I was asked to check how difficult is to play a video while downloading it from Internet. I know it's an easy task because someone told me a while ago. So, I checked and it was super easy.</p>
  
  <p>The problem was that I wanted to save to disk the video to do not force the user to download it again and again.</p>
  
  <p>The problem was to access the buffer and store it to disk. </p>
  
  <p>Many answers in Stackoverflow says it is nor possible. Specially with videos.</p>
  
  <p>My original code to play the video:</p>
  
  <pre><code>import AVFoundation
  
  ....
  
  //MARK: - Accessors
  
  lazy var player: AVPlayer = {
  
      var player: AVPlayer = AVPlayer(playerItem: self.playerItem)
  
      player.actionAtItemEnd = AVPlayerActionAtItemEnd.None
  
      return player
  }()
  
  lazy var playerItem: AVPlayerItem = {
  
      var playerItem: AVPlayerItem = AVPlayerItem(asset: self.asset)
  
      return playerItem
  }()
  
  lazy var asset: AVURLAsset = {
  
      var asset: AVURLAsset = AVURLAsset(URL: self.url)
  
      return asset
  }()
  
  lazy var playerLayer: AVPlayerLayer = {
  
      var playerLayer: AVPlayerLayer = AVPlayerLayer(player: self.player)
  
      playerLayer.frame = UIScreen.mainScreen().bounds
      playerLayer.backgroundColor = UIColor.clearColor().CGColor
  
      return playerLayer
  }()
  
  var url: NSURL = {
  
      var url = NSURL(string: "https://clips.vorwaerts-gmbh.de/big_buck_bunny.mp4")
  
      return url!
  }()
  
  //MARK: - ViewLifeCycle
  
  override func viewDidLoad() {
  
      super.viewDidLoad()
  
      view.layer.addSublayer(playerLayer)
  
      player.play()
  }
  </code></pre>