JSONNetworkingPlayground.swift

//: A UIKit based Playground for presenting user interface
  
import UIKit
import PlaygroundSupport

class MyViewController : UIViewController {
    override func loadView() {
        let view = UIView()
        view.backgroundColor = .white

        let label = UILabel()
        label.frame = CGRect(x: 150, y: 200, width: 200, height: 20)
        label.text = "Hello World!"
        label.textColor = .black
        
        view.addSubview(label)
        self.view = view
        
        let damageDeck = "https://raw.githubusercontent.com/guidokessels/xwing-data2/master/data/damage-decks/core.json"
        
        loadJSON(from: damageDeck)
    }
    
    func loadJSON(from: String) {
        // validate the incoming url
        guard let url = URL(string: from) else {
            print("Invalid url: \(from)")
            return
        }
        
        let request = URLRequest(url: url)
        let config = URLSessionConfiguration.default
        let session = URLSession(configuration: config)
        
        let task = session.dataTask(with: request) {
            (data, response, error) in
            
            // do we have an error?
            guard error == nil else {
                print("Error encountered requesting \(from), \(String(describing: error))")
                return
            }
            
            // do we have data?
            guard let response = data else {
                print("Error: did not receive data")
                return
            }
            
            // parse data, this code is dependent on the structure of the JSON
            /*
             Since we have a dictionary that has a key of type String and a value
             of type [Any], we'll need to first parse the JSON into a dictionary
             
             {
                "cards": [
                {
                "title": "Panicked Pilot",
                "amount": 2,
                "type": "Pilot",
                "text": "Gain 2 stress tokens. Then repair this card."
                },
                {
                "title": "Blinded Pilot",
                "amount": 2,
                "type": "Pilot",
                "text": "While you perform an attack, you can modify your 
                         dice only by spending [Force] for their default effect. 
                         Action: Repair this card."
                }
            }
            */
            print(response.description)
            
            do {
                // json root
                guard let rootDictionary = try JSONSerialization.jsonObject(
                    with: response,
                    options: []) as? [String: Any] else {
                    print("error trying to convert data to JSON")
                    return
                }
                
                // cards dictionary
                if let cards = rootDictionary["cards"] as? [[String: Any]] {
                    for card in cards {
                        if let title = card["title"] as? String {
                            print(title)
                        }
                    }
                }
            } catch  {
                print("failed to serialize data to JSON")
                return
            }
        }
        
        task.resume()
    }
}
// Present the view controller in the Live View window
PlaygroundPage.current.liveView = MyViewController()