How to use access token from response using swift 3 - ios

Question

So am making a login application that sends username and password, and the server replies with access token....am trying to save this token for later use but i really cant. here is my code, and the server response incase you need it
import UIKit
class ViewController: UIViewController {
#IBOutlet weak var PhoneNumber: UITextField!
#IBOutlet weak var Password: UITextField!
//***************************************LogIn**********************************************\\
#IBAction func Login(_ sender: UIButton) {
guard let url = URL(string: "https://goollyapp.azurewebsites.net/Token") else {return}
var request = URLRequest(url: url)
request.httpMethod = "POST"
let postString = "username=" + PhoneNumber.text! + "&password="+Password.text!+"&grant_type=password"
print(postString)
request.httpBody = postString.data(using: .utf8)
let task = URLSession.shared.dataTask(with: request) { data, response, error in
if let response = response {
print(response)
}
}
task.resume()
}
}

Answer 1

Where you declare the json variable replace with:
let json = try? JSONSerialization.jsonObject(with: data, options: []) as! [String: Any]
Then you can access the token with:
let token = json["access_token"] as! String
(after receiving a successful JSON response)
You can then implement a Singleton as follows:
class Token {
// Can't init a singleton
private init() { }
static let sharedInstance = Token()
var tokenString = ""
}

Answer 2

If you want to save the token in a variable for using it later , try this
(key being the corresponding name of the key in your response object)
let token = httpResponse?.allHeaderFields["SECURITY-TOKEN"] as? String
let task = URLSession.shared.dataTask(with: request) { data, response, error in
let httpResponse = response as? HTTPURLResponse
let token = httpResponse?.allHeaderFields["SECURITY-TOKEN"] as? String
print(token)
}
task.resume()