Facebook SDK inside iOS app extension cannot find logged in user? - ios-app-extension

Question

I've created a sample app Share extension. Followed the Apple guides, which means my project consists of a main app and a "share extension" target.
I've setup my Facebook SDK inside the main app, since the app's settings has some FB login/status functionality. It works well according to expectation: users can login and do some shares.
But I also want the logged-in user to be available to the extension target itself. When my extension comes up (in any app), I check Facebook's login status in viewDidLoad:, and it outputs "not logged in":
if ([FBSDKAccessToken currentAccessToken]) {
NSLog(#"logged in");
} else {
NSLog(#"not logged in");
}
The same code outputs "logged in" if called from within the main app. I suspect it has something to do with the fact that the extension target has a different bundle ID that looks like this: .suffix and I guess FB SDK is trying to read the user ID off the keychain cache, but maybe it's reading it off the wrong keychain due to the different bundle IDs... But it could be other reasons as well I guess.
Any idea how to keep Facebook SDK "logged in" inside the extension after the login itself occurred in the containing main app?

Answer 1

I have the exact same problem, as I develop a Message Extension App with a Facebook Login.
To solve the problem, I put the Login Button in the App and use the shared UserDefaults (with a group name) to store a property :
/*
* Get / sets if is FB connected (because we can't use FB SDK in Extension)
*/
public var isFacebookConnected : Bool {
get {
// Getting Bool from Shared UserDefaults
let defaults : NSUserDefaults = NSUserDefaults.init(suiteName: "MY_GROUP_NAME")!
let isFBConnected : Bool? = defaults.boolForKey("IsFacebookConnected")
if isFBConnected == nil {
return false
} else {
return isFBConnected!
}
}
set {
// Setting in UserDefaults
let defaults : NSUserDefaults = NSUserDefaults.init(suiteName: "MY_GROUP_NAME")!
defaults.setBool(newValue, forKey: "IsFacebookConnected")
defaults.synchronize()
}
}
This property is accessed from the App or from the Extension.
Then, in my Login / Logout methods I add :
//FBLogin
func loginButton(loginButton: FBSDKLoginButton!, didCompleteWithResult result: FBSDKLoginManagerLoginResult!, error: NSError!) {
if let error = error {
print(error.localizedDescription)
return
}
if result.isCancelled
{
return
}
// Set in Shared UserDefaults if connected / not connected
ConfigManager.sharedInstance.isFacebookConnected = true
...
}
func loginButtonDidLogOut(loginButton: FBSDKLoginButton!) {
// OK, keeping track
ConfigManager.sharedInstance.isFacebookConnected = false
}
Then, I keep track of my flag when login / logout.
Warning : this method is not bullet proof as I can't know if Facebook has been uninstalled, but it is robust enough for me.

Answer 2

I believe you'll need to take advantage of Keychain sharing capability in the app and extension to solve this.
https://developer.apple.com/documentation/security/keychain_services/keychain_items/sharing_access_to_keychain_items_among_a_collection_of_apps