Facebook Login not going back to App when migrated to Swift 3

Question

I have created a sample app where User logs in using Facebook Login button.

Once logged in I display User's Name and Email on Login screen. It was working with Swift 2.3. Once I migrated to Swift 3, it stopped working.

• Step1: Login with Facebook Login Button
• Step2: Allow permissions for email and profile
• Step3: Here it should go back to screen 1. But it doesn't. Attaching the Log I get when I click "Ok" button.

Update 1: App runs fine on iOS 9.3. The issue occurs only on iOS 10 devices.

2016-06-19 08:30:09.300070 MyApp[13942:1214112] [] nw_endpoint_handler_start [4 graph.facebook.com:443 initial path (null)]
2016-06-19 08:30:09.300484 MyApp[13942:1214112] [] nw_connection_endpoint_report [4 graph.facebook.com:443 initial path (null)] reported event path:start
2016-06-19 08:30:09.301255 MyApp[13942:1214112] [] nw_connection_endpoint_report [4 graph.facebook.com:443 waiting path (satisfied)] reported event path:satisfied
2016-06-19 08:30:09.302664 MyApp[13942:1214112] [] nw_connection_endpoint_report [4 graph.facebook.com:443 in_progress resolver (satisfied)] reported event resolver:start_dns
2016-06-19 08:30:09.348956 MyApp[13942:1214130] [] nw_endpoint_resolver_update [4 graph.facebook.com:443 in_progress resolver (satisfied)] Adding endpoint handler for 31.13.79.246:443
2016-06-19 08:30:09.349570 MyApp[13942:1214130] [] nw_connection_endpoint_report [4 graph.facebook.com:443 in_progress resolver (satisfied)] reported event resolver:receive_dns
2016-06-19 08:30:09.350027 MyApp[13942:1214130] [] nw_endpoint_resolver_start_next_child [4 graph.facebook.com:443 in_progress resolver (satisfied)] starting child endpoint 31.13.79.246:443
2016-06-19 08:30:09.350564 MyApp[13942:1214130] [] nw_host_stats_add_src recv too small, received 24, expected 28
2016-06-19 08:30:09.351022 MyApp[13942:1214130] [] nw_endpoint_resolver_start_next_child [4 graph.facebook.com:443 in_progress resolver (satisfied)] starting next child endpoint in 250ms
2016-06-19 08:30:09.351479 MyApp[13942:1214130] [] nw_endpoint_handler_start [4.1 31.13.79.246:443 initial path (null)]
2016-06-19 08:30:09.351862 MyApp[13942:1214130] [] nw_connection_endpoint_report [4.1 31.13.79.246:443 initial path (null)] reported event path:start
2016-06-19 08:30:09.352596 MyApp[13942:1214130] [] nw_connection_endpoint_report [4.1 31.13.79.246:443 waiting path (satisfied)] reported event path:satisfied
2016-06-19 08:30:09.352915 MyApp[13942:1214130] [] __nwlog_err_simulate_crash_libsystem libsystem simulate crash unavailable, [libsystem_network.dylib: nw_endpoint_get_hostname :: incorrect endpoint type 1]
2016-06-19 08:30:09.353524 MyApp[13942:1214130] [] nw_endpoint_get_hostname incorrect endpoint type 1, dumping backtrace:
        [x86_64] libnetcore-805.0.0.2.2
    0   libsystem_network.dylib             0x000000011186037f __nw_create_backtrace_string + 123
    1   libsystem_network.dylib             0x000000011186246e nw_endpoint_get_hostname + 75
    2   libnetwork.dylib                    0x0000000112bc4be7 nw_endpoint_proxy_handler_should_use_proxy + 125
    3   libnetwork.dylib                    0x0000000112bd204f nw_endpoint_handler_path_change + 1509
    4   libnetwork.dylib                    0x0000000112bd18a2 nw_endpoint_handler_start + 570
    5   libnetwork.dylib                    0x0000000112be8026 nw_endpoint_resolver_start_next_child + 2050
    6   libdispatch.dylib                   0x00000001115b91e8 _dispatch_call_block_and_release + 12
    7   libdispatch.dylib                   0x00000001115e5dee _dispatch_client_callout + 8
    8   libdispatch.dylib                   0x00000001115c0a1d _dispatch_queue_serial_drain + 239
    9   libdi
2016-06-19 08:30:09.357989 MyApp[13942:1214130] [] nw_connection_endpoint_report [4.1 31.13.79.246:443 in_progress socket-flow (satisfied)] reported event flow:start_connect
2016-06-19 08:30:09.468327 MyApp[13942:1214130] [] nw_endpoint_flow_protocol_connected [4.1 31.13.79.246:443 in_progress socket-flow (satisfied)] Output protocol connected
2016-06-19 08:30:09.469541 MyApp[13942:1214130] [] nw_endpoint_flow_connected_path_change [4.1 31.13.79.246:443 ready socket-flow (satisfied)] Connected path is satisfied
2016-06-19 08:30:09.470103 MyApp[13942:1214130] [] nw_connection_endpoint_report [4.1 31.13.79.246:443 ready socket-flow (satisfied)] reported event flow:finish_connect
2016-06-19 08:30:09.470858 MyApp[13942:1214130] [] nw_connection_endpoint_report [4 graph.facebook.com:443 ready resolver (satisfied)] reported event flow:finish_connect
2016-06-19 08:30:09.471427 MyApp[13942:1214130] [] nw_connection_endpoint_report [4.1 31.13.79.246:443 ready socket-flow (satisfied)] reported event flow:changed_viability
2016-06-19 08:30:09.471870 MyApp[13942:1214130] [] nw_connection_endpoint_report [4 graph.facebook.com:443 ready resolver (satisfied)] reported event flow:changed_viability
2016-06-19 08:30:09.472479 MyApp[13942:1214112] [] nw_endpoint_start_tls_while_connected [4.1 31.13.79.246:443 ready socket-flow (satisfied)]
2016-06-19 08:30:09.473243 MyApp[13942:1214112] [] nw_connection_endpoint_report [4.1 31.13.79.246:443 in_progress socket-flow (satisfied)] reported event flow:start_secondary_connect
2016-06-19 08:30:09.473685 MyApp[13942:1214112] [] nw_connection_endpoint_report [4 graph.facebook.com:443 in_progress resolver (satisfied)] reported event flow:start_secondary_connect
2016-06-19 08:30:09.474206 MyApp[13942:1214112] [] nw_connection_endpoint_report [4.1 31.13.79.246:443 in_progress socket-flow (satisfied)] reported event flow:start_connect
2016-06-19 08:30:09.474740 MyApp[13942:1214112] [] nw_connection_endpoint_report [4 graph.facebook.com:443 in_progress resolver (satisfied)] reported event flow:start_connect
2016-06-19 08:30:09.475123 MyApp[13942:1214112] [] nw_endpoint_flow_protocol_connected [4.1 31.13.79.246:443 in_progress socket-flow (satisfied)] Transport protocol connected
2016-06-19 08:30:09.475502 MyApp[13942:1214112] [] nw_connection_endpoint_report [4.1 31.13.79.246:443 in_progress socket-flow (satisfied)] reported event flow:finish_transport
2016-06-19 08:30:09.475834 MyApp[13942:1214112] [] nw_connection_endpoint_report [4 graph.facebook.com:443 in_progress resolver (satisfied)] reported event flow:finish_transport
2016-06-19 08:30:09.586843 MyApp[13942:1214130] [] nw_endpoint_flow_protocol_connected [4.1 31.13.79.246:443 in_progress socket-flow (satisfied)] Output protocol connected
2016-06-19 08:30:09.588117 MyApp[13942:1214130] [] nw_endpoint_flow_connected_path_change [4.1 31.13.79.246:443 ready socket-flow (satisfied)] Connected path is satisfied
2016-06-19 08:30:09.588724 MyApp[13942:1214130] [] nw_connection_endpoint_report [4.1 31.13.79.246:443 ready socket-flow (satisfied)] reported event flow:finish_connect
2016-06-19 08:30:09.589299 MyApp[13942:1214130] [] nw_connection_endpoint_report [4 graph.facebook.com:443 ready resolver (satisfied)] reported event flow:finish_connect

Here is my Code.

ViewController

import UIKit
import FBSDKCoreKit
import FBSDKLoginKit
import Firebase

class ViewController: UIViewController, FBSDKLoginButtonDelegate{

    // Properties
    @IBOutlet weak var usernameTextField: UITextField!
    @IBOutlet weak var usernameLabel: UILabel!
    @IBOutlet weak var submitButton: UIButton!
    @IBOutlet weak var fbLoginBtn: FBSDKLoginButton!
    var ref:FIRDatabaseReference!

    private let dataurl = "https://project-URL/"

    override func viewDidLoad() {
        super.viewDidLoad()
        self.ref = FIRDatabase.database().reference()
        fbLoginBtn.delegate = self
        fbLoginBtn.readPermissions = ["email"]
        // Do any additional setup after loading the view, typically from a nib.
    }

    //Actions
    @IBAction func onSubmitBtnPressed(_ sender: UIButton) {
        usernameLabel.text = usernameTextField.text;
    }

    func loginButton(_ loginButton: FBSDKLoginButton!, didCompleteWith result: FBSDKLoginManagerLoginResult!, error: NSError!) {
        print("User Logged In")

        if ((error) != nil)
        {
            // Process error
            print("error")
        }
        else if result.isCancelled {
            // Handle cancellations
            print("cancelled")
        }
        else {
            // If you ask for multiple permissions at once, you
            // should check if specific permissions missing
            if result.grantedPermissions.contains("email")
            {
                let credential = FIRFacebookAuthProvider.credential(withAccessToken: FBSDKAccessToken.current().tokenString)
                // Do work
                print("logged in ")
                FIRAuth.auth()?.signIn(with: credential, completion: { (user, error) in
                    if (user != nil) {

                        let uid = user?.uid as String!

                        self.fetchProfile(uid!);
                    }
                })
            }
        }
    }

    func loginButtonDidLogOut(_ loginButton: FBSDKLoginButton!) {
        print("User Logged Out")
    }

    func fetchProfile(_ uid: String) {
        let parameters = ["fields": "email, first_name, last_name, picture.type(large)"]
         var userinfo: [String:String] = [:]
        FBSDKGraphRequest(graphPath: "me", parameters: parameters).start(completionHandler: { (connection, user, requestError) -> Void in

            if requestError != nil {
                print(requestError)

            }

            userinfo["email"] = user?["email"] as? String
            userinfo["firstname"] = user?["first_name"] as? String
            userinfo["lastname"] = user?["last_name"] as? String
            self.ref.child("users").child(uid).setValue(userinfo)
        })
    }
}

AppDelegate

import UIKit
import Firebase
import FirebaseDatabase
import FBSDKCoreKit
import FBSDKLoginKit

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?


    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
        // Override point for customization after application launch.

        // Use Firebase library to configure APIs
        FIRApp.configure()
        FIRDatabase.database().persistenceEnabled = true
        return FBSDKApplicationDelegate.sharedInstance()
            .application(application, didFinishLaunchingWithOptions: launchOptions)
    }

    func application(_ application: UIApplication, open url:URL,sourceApplication: String?, annotation: AnyObject) -> Bool {
        return FBSDKApplicationDelegate.sharedInstance()
            .application(application, open: url,
                         sourceApplication: sourceApplication, annotation: annotation)
    }

    func applicationDidBecomeActive(_ application: UIApplication) {
        // Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
        FBSDKAppEvents.activateApp()
    }
}

Login Screen

Answer 1

Facebook docs need to be updated.

For iOS 9+, rather than using:

func application(_ application: UIApplication, open url:URL, sourceApplication: String?, annotation: AnyObject) -> Bool

You should be using:

func application(_ app: UIApplication, open url: URL, options: [String : AnyObject] = [:]) -> Bool {
    return FBSDKApplicationDelegate.sharedInstance().application(application,
                                                                 openURL: url,
                                                                 sourceApplication: options[UIApplicationOpenURLOptionsSourceApplicationKey] as! String,
                                                                 annotation: options [UIApplicationOpenURLOptionsAnnotationKey])
}

Answer 2

Seems like options[UIApplicationOpenURLOptionsAnnotationKey] doesn't work anymore. now you have to do it like this: options[UIApplicationOpenURLOptionsKey.sourceApplication]

This is what works for me

func application(_ app: UIApplication, open url: URL, options: [UIApplicationOpenURLOptionsKey : Any] = [:]) -> Bool {

    return FBSDKApplicationDelegate.sharedInstance()
                                   .application(app, 
                                               open: url,
                                  sourceApplication: options[UIApplicationOpenURLOptionsKey.sourceApplication] as! String,
                                         annotation: options[UIApplicationOpenURLOptionsKey.annotation])
}