In this video, we go over how to pull JSON data from the internet to build out our dynamic home feed. First, I'll show you how to execute an NSURLSession task to complete a fetch request. Next, we iterate through all the objects in this JSON dictionary and construct all of our video objects. Finally, we update our cell images based on the image urls returned.

!codebreak <div class='filename'>HomeController.swift</div> !codebreak !syntax-highlight func fetchVideos() { let url = NSURL(string: "https://s3-us-west-2.amazonaws.com/youtubeassets/home.json") NSURLSession.sharedSession().dataTaskWithURL(url!) { (data, response, error) in if error != nil { print(error) return } do { let json = try NSJSONSerialization.JSONObjectWithData(data!, options: .MutableContainers) self.videos = [Video]() for dictionary in json as! [[String: AnyObject]] { let video = Video() video.title = dictionary["title"] as? String video.thumbnailImageName = dictionary["thumbnail_image_name"] as? String let channelDictionary = dictionary["channel"] as! [String: AnyObject] let channel = Channel() channel.name = channelDictionary["name"] as? String channel.profileImageName = channelDictionary["profile_image_name"] as? String video.channel = channel self.videos?.append(video) } self.collectionView?.reloadData() } catch let jsonError { print(jsonError) } }.resume() } !codebreak <div class='filename'>VideoCell.swift</div> !codebreak !syntax-highlight class VideoCell: BaseCell { var video: Video? { didSet { titleLabel.text = video?.title setupThumbnailImage() setupProfileImage() if let channelName = video?.channel?.name, numberOfViews = video?.numberOfViews { let numberFormatter = NSNumberFormatter() numberFormatter.numberStyle = .DecimalStyle let subtitleText = "\(channelName) • \(numberFormatter.stringFromNumber(numberOfViews)!) • 2 years ago " subtitleTextView.text = subtitleText } //measure title text if let title = video?.title { let size = CGSizeMake(frame.width - 16 - 44 - 8 - 16, 1000) let options = NSStringDrawingOptions.UsesFontLeading.union(.UsesLineFragmentOrigin) let estimatedRect = NSString(string: title).boundingRectWithSize(size, options: options, attributes: [NSFontAttributeName: UIFont.systemFontOfSize(14)], context: nil) if estimatedRect.size.height > 20 { titleLabelHeightConstraint?.constant = 44 } else { titleLabelHeightConstraint?.constant = 20 } } } } func setupProfileImage() { if let profileImageUrl = video?.channel?.profileImageName { userProfileImageView.loadImageUsingUrlString(profileImageUrl) } } func setupThumbnailImage() { if let thumbnailImageUrl = video?.thumbnailImageName { thumbnailImageView.loadImageUsingUrlString(thumbnailImageUrl) } } //... } !codebreak <div class='filename'>UIImageView</div> !codebreak !syntax-highlight extension UIImageView { func loadImageUsingUrlString(urlString: String) { let url = NSURL(string: urlString) NSURLSession.sharedSession().dataTaskWithURL(url!, completionHandler: { (data, respones, error) in if error != nil { print(error) return } dispatch_async(dispatch_get_main_queue(), { self.image = UIImage(data: data!) }) }).resume() } }