Facebook openSession

gistfile1.m

+(void)handleSessionWithCompletion:(void (^)(void))completion {
    if (FBSession.activeSession.isOpen) {
        completion();
    } else {
        NSArray *permissions = @[@"user_birthday"];
        [FBSession openActiveSessionWithReadPermissions:permissions
                                           allowLoginUI:YES completionHandler:^(FBSession *session,
                                                                                FBSessionState status,
                                                                                NSError *error) {
                                               if (error) {
                                                   [SVProgressHUD dismiss];
                                                   UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Error"
                                                                                                   message:error.localizedDescription
                                                                                                  delegate:nil cancelButtonTitle:@"OK"
                                                                                         otherButtonTitles:nil];
                                                   [alert show];
                                               } else if (FB_ISSESSIONOPENWITHSTATE(status)) {
                                                   ALog(@"Facebook expiration date: %@",FBSession.activeSession.accessTokenData.expirationDate);
                                                   completion();
                                               }
                                           }];
    }
}