Facebook SSO problems with iOS app

Question

I'm trying to integrate Facebook to my app, I've implemented the SSO feature, however I ran into a bit of a snag, once I quit the app I am unable to restore the user's session. I store the token and expiry date as shown:

-(void)fbDidLogin {
NSString *tokenString = [[self facebook] accessToken];
NSDate * expirationDate = [[self facebook] expirationDate];

[[NSUserDefaults standardUserDefaults] setValue: tokenString forKey:@"FacebookToken"];
[[NSUserDefaults standardUserDefaults] setObject: expirationDate forKey:@"FacebookExpirationDate"];
[[NSUserDefaults standardUserDefaults] synchronize];
NSLog(@"Login");

}

this is the delegate method called upon successful login.

and resume the session:

  NSString *tokenString = [[NSUserDefaults standardUserDefaults] stringForKey:@"FacebookToken"];    
NSDate *expDate = [[NSUserDefaults standardUserDefaults] objectForKey:@"FacebookExpirationDate"];
if (tokenString != nil && expDate != nil)
{
    [[facebookFetcher facebook]setAccessToken:tokenString];
    [[facebookFetcher facebook] setExpirationDate:expDate];
}
if ([[facebookFetcher facebook]  isSessionValid])
{
    NSLog(@"YES");
}
else 
{
    NSLog(@"Bummer");
}

I've tried tackling the problem in a number of ways without luck. One thing I've noticed is that the expiry date seems to be a bit weird: 4001-01-01 00:00:00 +0000 Any suggestions? Thanks.

Answer 1

Your answer is at the following link

Does the Facebook iOS SDK require the user to authenticate every time they use the app?

Answer 2

The date 4001-01-01 00:00:00 +0000 is seen when using the extended permission offline_access .

I ran into trouble with this because I was converting the date into "seconds since 1970" like how it's done on the Android Facebook SDK. If you convert 4001-01-01 to seconds using NSDate 's timeIntervalSince1970 , you'll get a negative number (-2147483648), so watch out.