Linking Parse and Facebook causes Facebook session to close - ios

Question

I am using Parse for my backend on my iOS application, and I am trying to use a FBLoginView to allow users to login with Facebook.
I am also trying to link the user's Facebook account to their Parse account. When I attempt to link the user to their FB by using
if (![PFFacebookUtils isLinkedWithUser:user]) {
[PFFacebookUtils linkUser:user permissions:nil block:^(BOOL succeeded, NSError *error) {
if (succeeded) {
NSLog(#"Woohoo, user logged in with Facebook!");
}
}];
}
I receive an error telling me that the Facebook session is invalid. I have determined that the above code seems to be closing the Facebook session (when I comment out the code, the session does not close) and giving me the error. Does anyone have any experience with this error?

Answer 1

Do your other apps use Parse for the backend?
The user state stored in PFFacebookUtils is different from the user returned from the FBLoginView.
If your code looks like this:
#pragma mark FBLoginViewDelegate {
- (void)loginViewFetchedUserInfo:(FBLoginView *)loginView
user:(id<FBGraphUser>)user {
// link current user
NSLog(#"User: %#", user);
if (![PFFacebookUtils isLinkedWithUser:user]) {
[PFFacebookUtils linkUser:user permissions:nil block:^(BOOL succeeded, NSError *error) {
if (succeeded) {
NSLog(#"Woohoo, user logged in with Facebook!");
}
}];
}
}
Then you are currently linking a Facebook user object with a PFUser, which are incompatible. I would suggest using the data that the FBLoginView returns, and creating a parse user in the conventional way:
#pragma mark FBLoginViewDelegate {
- (void)loginViewFetchedUserInfo:(FBLoginView *)loginView
user:(id<FBGraphUser>)user {
// link current user
NSLog(#"User: %#", user);
NSString *username = user[#"email"];
NSString *password = user[#"id"];
[PFUser logInWithUsernameInBackground:username password:password block:^(PFUser *user, NSError *error) {
NSLog(#"User: %#", user);
if (error.code == 101) {
// sign up
PFUser *user = [PFUser user];
user.username = username;
user.password = password;
[user signUpInBackgroundWithBlock:^(BOOL succeeded, NSError *error) {
NSLog(#"Error: %#", error);
}];
}
}];
}
Now [PFUser currentUser] will return a parse user object, that was created based on your Facebook login. If the app is deleted/reinstalled, the next time the user enters the app, the FBLoginView will return a userid that will be used to log in to parse as an existing user.
Edit: A similar issue I've had is with using FBLogin, PFFacebookUtils, and any other recent facebook app logins if my phone has Facebook integrated into iOS settings. It seems to have something to do with the Apple integration of Facebook, and the new Facebook SDKs. It's annoying but I have to currently tell my users to delete their facebook information from the Settings, then they can login, using either PFFacebookUtils, or the process above. I hope this gets resolved soon.

Answer 2

for the first part of your question i'd found a way to login user into my app by just using Facebook with Parse. Actually once the users use this, you can check the data browser of your app and check the auth data filed and the profile filed with all the fb data that i did request within the app.
here is the code i use to login with fb, haven't linked a previous user with a fb account
- (IBAction)loginButtonTouchHandler:(id)sender {
// The permissions requested from the user
NSArray *permissionsArray = #[ #"user_about_me", #"user_relationships", #"user_birthday", #"user_location"];
// Login PFUser using Facebook
[PFFacebookUtils logInWithPermissions:permissionsArray block:^(PFUser *user, NSError *error) {
//[_activityIndicator stopAnimating]; // Hide loading indicator
if (!user) {
if (!error) {
NSLog(#"Uh oh. The user cancelled the Facebook login.");
} else {
NSLog(#"Uh oh. An error occurred: %#", error);
}
} else if (user.isNew) {
NSLog(#"User with facebook signed up and logged in!");
//Go to your next view
} else {
NSLog(#"User with facebook logged in!");
//Go to your next view
}
}];
}
Hope this helps!