Increment counter for currentUser - objective-c

Question

I would like to increment a counter for a given currentUser's key.
I'm using the incrementKey method, however, the following code is not working*:
[currentUser incrementKey:#"likes" byAmount:[NSNumber numberWithInt:1]];
[currentUser saveInBackground];
It doesn't raise an error, but it doesn't update the database either.

Answer 1

Supposing that current User is a PFUser instance, if it is not the current logged user [PFUser currentUser], probably you should have the right ACL on that user row.
Try to set the current ACL field for that user for read and write, eg:
// set user acl
PFACL* userACL = [PFACL ACLWithUser:currentUser];
[userACL setPublicReadAccess:YES];
[userACL setPublicWriteAccess:YES];
[currentUser setACL:userACL];
[currentUser saveInBackgroundWithBlock:^(BOOL succeeded, NSError *error) {
// check if any save error occurs
}];
Honestly, i suggest to don't use the above approach for security reason, especially on the User table. Instead you could try to make a custom function Cloud code side, using the Parse.Cloud.useMasterKey() and so increment the user with something like
.
..
...
Parse.Cloud.useMasterKey();
...
// retrieve the user with passed user object id from client
var userId =request.params.myUserId;
var user = new Parse.User();
user.set("objectId", userId);
user.fetch().then(function(concreteUser){
concreteUser.increment("likes", 1);
concreteUser.save().then(function(incrementedUser){
response.success();
},function(saveError){
response.error(saveError);
});
},function(error){
response.error(error);
});
Hope it helps