16.0.1 FB SDK doesn't keep user logged in on subsequent sessions

[vnavarro]

Hi,

I've already opened it on a previous channel but was wrongly dismissed

https://developers.facebook.com/support/bugs/297755336112477/

So, I will give all info here.

Checklist

• I've updated to the latest released version of the SDK.
• I've searched for existing GitHub issues
• I've looked for existing answers on Stack Overflow, the Facebook Developer Community Forum and the Facebook Developers Group
• I've read the Code of Conduct
• This issue is not security related and can safely be disclosed publicly on GitHub

Environment

Unity Editor Version: 2021.3.25f1
Unity FB SDK 16.0.1
Builds: iOS and Android. Any version.

Goals

Use FB Login with a user-provided FB account so user will be logged in with FB in the game.

Expected Results

After the user logs in with Facebook login is not requested from the user until the token is expired, regardless of the game being closed.

Actual Results

The user logs in and has a valid non-expired access token with further away expiration in the future, when the game is closed and opened again FB SDK does not identify the user being logged in so it will ask the user for login again, no matter how many times it does never save it.

Steps to Reproduce

1 - Create Unity project and add FB SDK (16.0.1) to it (iOS/Android devices)
2 - Initialize Facebook SDK (FB.Init) and ask user to login FB.LogInWithReadPermissions use gaming_profile permission
3 - With the user successfully logged in close and kill the game
4 - Reopen the game, and check that after initializing facebook it still needs login (FB.IsInitialized = true and FB.IsLoggedIn = false)

Code Samples & Details

FB.Init(onInitComplete: () => {
  if (!FB.IsLoggedIn)
  {
    FB.LogInWithReadPermissions(FacebookSDKNeededPermissions, result => { });
  }
});

[mmunson-aftershock]

Only a problem with iOS as far as I can tell. The breaking commit was 7ba25ae

[AvivWhalo]

bump, we're also suffering the same problem

[dreamcodestudio]

Same issue on iOS
after bump Facebook from 15.1.0 to 16.0.1

[MTPirate89]

bump, we're experiencing same issue after update(

[AdeelAhmed60]

You need to wait for the main thread after initializing the "FB.Init" Facebook sdk but if error still occur try refreshing current access token after confirming if user logged in
FB.Mobile.RefreshCurrentAccessToken Hope this will help

[lymancao]

Same issue on iOS for Unity FB SDK 16.0.2

[lymancao]

You need to wait for the main thread after initializing the "FB.Init" Facebook sdk but if error still occur try refreshing current access token after confirming if user logged in FB.Mobile.RefreshCurrentAccessToken Hope this will help

This is the right answer.

1. wait a second for FB.IsLoggedIn to become true.
2. AccessToken.CurrentAccessToken is null now
3. call FB.Mobile.RefreshCurrentAccessToken to get AccessToken

[dvgco]

After the fixed in Unity FB SDK 17.0.1
There are new problem on my side, when logged in subsequent sessions, the AccessToken.CurrentAccessToken is null after FB.Init, then the FB.IsLoggedIn is true but AccessToken.CurrentAccessToken is null on iOS platform.

Finally, I found the reason is that didFinishLaunching in FBUnityInterface.mm called after the FB.Init (Called on awake) on my code, it's caused the AccessToken.CurrentAccessToken keeps null all the runtime if not call FB.Mobile.RefreshCurrentAccessToken to get AccessToken.

This is the order of execution:

1. call UnityAppController 'didFinishLaunching'
2. call GameObject awake in Unity (FB.Init here, and then send 'OnInitComplete' message to Unity with null access token)
3. call FBSDKApplicationDelegate 'didFinishLaunching' (FB initializeSDK here, sync load the accesstoken cache)

I think the right call order should be 1 -> 3 -> 2

why could not FB initializeSDK in IOSFBInit funtion?