Query PFRelation of blocked users - ios

Question

I'm trying to query the 'friend' relation while excluding any friends that have blocked the user (which is stored as a relation<_user>) on the friends user with a relation to the user they are blocking (potentially the user checking their friends). I tried querying like below, but it isn't excluding the record like I would think:
[SVProgressHUD showWithStatus:#"Loading ..."];
[friends removeAllObjects];
PFRelation *friendRelation = [[PFUser currentUser] objectForKey:#"friendsRelation"];
if (friendRelation)
{
PFQuery *friendsQuery = [friendRelation query];
[friendsQuery orderByAscending:#"firstname"];
[friendsQuery whereKey:#"disabled" notEqualTo:[NSNumber numberWithBool:YES]];
[friendsQuery whereKey:#"Blocked" notEqualTo:[PFUser currentUser]];
[friendsQuery findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error)
{
if (!error)
{
friends = [objects mutableCopy];
[self.myTableView reloadData];
[SVProgressHUD dismiss];
}
else
{
[SVProgressHUD showErrorWithStatus:#"Loading failed. Please try again."];
}
}];
}
else
{
[SVProgressHUD dismiss];
}
Is there a way to accomplish what I am trying to do?

Answer 1

I had the same issue in one of my projects and solved it as follows. I created a class "blocked" and once a user blocks another user, I simply create two objects there. I did this in a general helper class, by creating a method (user1 is the current user, user2 is the other user):
void BlockUserOne(PFUser *user1, PFUser *user2)
{
PFQuery *query = [PFQuery queryWithClassName:PF_BLOCKED_CLASS_NAME];
[query whereKey:PF_BLOCKED_USER equalTo:[PFUser currentUser]];
[query whereKey:PF_BLOCKED_USER1 equalTo:user1];
[query whereKey:PF_BLOCKED_USER2 equalTo:user2];
[query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error)
{
if (error == nil)
{
if ([objects count] == 0)
{
PFObject *object = [PFObject objectWithClassName:PF_BLOCKED_CLASS_NAME];
object[PF_BLOCKED_USER] = [PFUser currentUser];
object[PF_BLOCKED_USER1] = user1;
object[PF_BLOCKED_USER2] = user2;
object[PF_BLOCKED_USERID2] = user2.objectId;
[object saveInBackgroundWithBlock:^(BOOL succeeded, NSError *error)
{
if (error != nil) NSLog(#"BlockUserOne save error.");
}];
}
}
else NSLog(#"BlockUserOne query error.");
}];
}
This method creates an object in the blocked class, containing the two users that are part of the blocking process, as well as a third field with the user that initially did the blocking. This method is called two times, and user1 is always the current user:
PFUser *user1 = [PFUser currentUser];
BlockUserOne(user1, user2);
BlockUserOne(user2, user1);
This creates two objects in the blocked class (two because this makes handling both users being part of the blocking process easier)
Now, as the objects exist in the blocked class, it's time to check against them when querying for users. Here is an example of searching for users with a search bar:
- (void)searchUsers:(NSString *)search
{
PFUser *user = [PFUser currentUser];
//Querying for users that have been blocked by the current user
//or have blocked the current user (therefore the two different
//objects that I created
PFQuery *query1 = [PFQuery queryWithClassName:PF_BLOCKED_CLASS_NAME];
[query1 whereKey:PF_BLOCKED_USER1 equalTo:user];
//We don't want to query the current user, don't we?
PFQuery *query2 = [PFQuery queryWithClassName:PF_USER_CLASS_NAME];
[query2 whereKey:PF_USER_OBJECTID notEqualTo:user.objectId];
//
//This is the crucial part!!
[query2 whereKey:PF_USER_OBJECTID doesNotMatchKey:PF_BLOCKED_USERID2 inQuery:query1];
//
//
[query2 whereKey:PF_USER_FULLNAME_LOWER equalTo:[search lowercaseString]];
[query2 orderByAscending:PF_USER_FULLNAME];
[query2 setLimit:1000];
[query2 findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error)
{
if (error == nil)
{
//Do whatever you want to do
}
else //Handle the error
}];
}
First, we query for all the users that have blocked the current user or have been blocked by the current user, and then we search for users that have not been returned by the first query.
This results in query2 returning users that have not been involved in a blocking process with the current user.
Hope this helps clearing up the situation.