Passing OAuth token between views programmatically in Swift - swift

Question

I am stuck on trying to pass a variable from one view to another. I am deliberately doing this all programmatically without Story Boards.
ViewController creates has a UIButton which when pressed calls the AuthoriseController.
AuthoriseController then loads a UIWebView, opening it at a particular URL e.g. https://foursquare.com/oauth2/authenticate?client_id=xxxxx&response_type=token&redirect_uri=yyyyy
This loads up an OAuth screen. After the user logs in, control comes back to AuthoriseController where I extract the access_token which is returned in the redirect URI.
The exctraction works great and I can get hold of the token, my problem is that I want to get the the token back to my ViewController so that when the user pushes the button again it will be available to an HTTP request (at the moment I’m just printing the token).
My ViewController and AuthoriseController implement a Protocol called DataProtocol which I was hoping could be used share the token between controllers.
ViewController:
import UIKit
class ViewController: UIViewController {
var delegate: DataProtocol? = nil
func setUpView(){
let firstView = UIView()
let button = UIButton.buttonWithType(UIButtonType.System) as UIButton
firstView.setTranslatesAutoresizingMaskIntoConstraints(false)
firstView.backgroundColor = UIColor(red: 0.75, green: 0.75, blue: 0.1, alpha: 1.0)
view.addSubview(firstView)
setUpButton(button)
firstView.addSubview(button)
setUpConstraints(firstView, button)
}
func setUpConstraints(firstView: UIView, _ button: UIButton) {
let viewsDictionary = ["firstView":firstView,"button":button]
let metricsDictionary = ["firstViewHeight":1334.0,"viewWidth":750.0 ]
let firstViewHeightConstraintH:NSArray = NSLayoutConstraint.constraintsWithVisualFormat("H:[firstView(viewWidth)]", options: NSLayoutFormatOptions(0), metrics: metricsDictionary, views: viewsDictionary)
let firstViewHeightConstraintV:NSArray = NSLayoutConstraint.constraintsWithVisualFormat("V:[firstView(firstViewHeight)]", options: NSLayoutFormatOptions(0), metrics: metricsDictionary, views: viewsDictionary)
firstView.addConstraints(firstViewHeightConstraintH)
firstView.addConstraints(firstViewHeightConstraintV)
let buttonConstraintH:NSArray = NSLayoutConstraint.constraintsWithVisualFormat("H:|-150-[button(>=80)]", options: NSLayoutFormatOptions.AlignAllCenterY, metrics: nil, views: viewsDictionary)
let buttonConstraintV:NSArray = NSLayoutConstraint.constraintsWithVisualFormat("V:|-300-[button]", options: NSLayoutFormatOptions(0), metrics: nil, views: viewsDictionary)
firstView.addConstraints(buttonConstraintH)
firstView.addConstraints(buttonConstraintV)
}
func setUpButton(button: UIButton) {
button.setTranslatesAutoresizingMaskIntoConstraints(false)
button.setTitle("Authorise", forState: UIControlState.Normal)
button.addTarget(self, action: "buttonPressed", forControlEvents: UIControlEvents.TouchUpInside)
button.backgroundColor = UIColor.blueColor()
button.setTitleColor(UIColor.whiteColor(), forState: UIControlState.Normal)
}
override func shouldAutorotate() -> Bool {
return false
}
func buttonPressed(){
let ac = AuthoriseController()
self.presentViewController(ac, animated: true, completion: nil)
println("token in ViewController.buttonPressed: [\(self.delegate?.token)]")
}
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = UIColor(red: 0.9, green: 0.9, blue: 1, alpha: 1.0)
setUpView()
}
override func supportedInterfaceOrientations() -> Int {
return Int(UIInterfaceOrientationMask.All.toRaw())
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
}
AuthoriseController:
import UIKit
import WebKit
class AuthoriseController: UIViewController, UIWebViewDelegate, DataProtocol {
var token: String = ""
let AUTH_URL = "https://foursquare.com/oauth2/authenticate?client_id=";
let RESP_TYPE_AND_KEY_AND_TOKEN = "&response_type=token&redirect_uri=";
let REDIRECT_URI : String = "ZZZZZZZZ";
let CLIENT_ID : String = "XXXXXXX";
var webview: UIWebView = UIWebView()
override func viewDidLoad() {
super.viewDidLoad()
var myViewController = ViewController()
self.webview.frame = self.view.bounds
self.webview.delegate = self
self.view.addSubview(self.webview)
var url: NSURL = NSURL.URLWithString(AUTH_URL + CLIENT_ID + RESP_TYPE_AND_KEY_AND_TOKEN + REDIRECT_URI)
var urlRequest: NSURLRequest = NSURLRequest(URL: url)
self.webview.loadRequest(urlRequest)
}
func webView(webView: UIWebView!, shouldStartLoadWithRequest request: NSURLRequest!, navigationType: UIWebViewNavigationType) -> Bool {
token = getToken(request.URL.absoluteString!)
println("token in AuthoriseController.webView: [\(token)]")
if(!token.isEmpty) {
self.dismissViewControllerAnimated(true, completion: nil)
}
return true
}
func getToken(url: String) -> String {
var token = ""
if url.rangeOfString("#access_token") != nil{
token = url.componentsSeparatedByString("=").last!
}
return token
}
}
Here is the DataProtocol:
import Foundation
protocol DataProtocol {
var token : String { get set }
}
When I doing this:
Starting the App
Pressing the Authorise button
Successfully logging in (control returns to ViewController
Pressing the button again
Output:I get this output:
token in ViewController.buttonPressed: [nil]
token in AuthoriseController.webView: []
token in AuthoriseController.webView: []
token in AuthoriseController.webView: []
token in AuthoriseController.webView: [VSKRNHJRS3NWPN3EEIYMCSZYJ2YMNSH4GBXNQFL1EMYLJ5TO]
token in ViewController.buttonPressed: [nil]
token in AuthoriseController.webView: []
token in AuthoriseController.webView: [VSKRNHJRS3NWPN3EEIYMCSZYJ2YMNSH4GBXNQFL1EMYLJ5TO]
I’d hoped to see the token in the second occurrence of ViewController.buttonPressed, instead of NIL.
Can anyone see where I am going wrong? Any help is greatly appreciated! Steve

Answer 1

It looks like the delegate is hooked up correctly but you aren't sending the token to it. In AuthoriseController, you need to set the token for the delegate:
func webView(webView: UIWebView!, shouldStartLoadWithRequest request: NSURLRequest!, navigationType: UIWebViewNavigationType) -> Bool {
token = getToken(request.URL.absoluteString!) // sets the token in the AuthoriseController
println("token in AuthoriseController.webView: [\(token)]")
if(!token.isEmpty) {
// pass the token to the delegate
self.delegate?.token = token
self.dismissViewControllerAnimated(true, completion: nil)
}
return true
}