insert an ObjectId in another user - Parse and Swift - arrays

Question

I am currently trying to save an objectId in another user's array. unfortunately, I am getting an error. here is what I tried :
let name = (PFUser.currentUser()!["FirstName"] as! String) + " " + (PFUser.currentUser()!["LastName"] as! String)
let News = News(title: "\(name) accepted your ...", user: PFUser.currentUser()!)
News.saveInBackgroundWithBlock({ (success: Bool, error: NSError?) -> Void in
if (success){
let user = self.interest.user as! User
user.joinNews(News.objectId!)
} else {
print("--------")
}
})
And here is the func joinNews I created for this :
public func joinNews(newsId: String) {
newsIds.insert(newsId, atIndex: 0)
saveInBackgroundWithBlock { (success, error) -> Void in
if error != nil {
print("\(error!.localizedDescription)")
}
}
}
Thanks in advance for you help !

Answer 1

The User object has a special security : it can only be updated by the user itself, that's why you get the error "User cannot be saved unless they have been authenticated via logIn or signUp"
If you want an action of the current user to modify another user object, you need to use a cloud code function, and use the Parse master key, to override this security.
This would look like :
Parse.Cloud.define("addNewsToUser", function(request, response) {
Parse.Cloud.useMasterKey();
var user = new Parse.User();
user.id = request.params.userId;
user.fetch().then(function(object) {
// modify the user here
return user.save();
}).then(function() {
response.success(user);
}, function(error) {
response.error(error.message);
});
});