CachePolicyWithParse

- (void)refreshData
{
    PFUser *currentUser = [PFUser currentUser];
    
    NSPredicate *predicate = [NSPredicate predicateWithFormat:[NSString stringWithFormat:@"%@ = '%@' OR %@ = '%@'",
                                                               kMessageUserSendIdKey, currentUser.objectId,
                                                               kMessageUserReceiveIdKey, currentUser.objectId]];
    
    PFQuery *query = [PFQuery queryWithClassName:kMessageClassKey predicate:predicate];
    [query addDescendingOrder:kMessageTimeCreatedKey];
    [query includeKey:kMessageUserSendKey];
    [query includeKey:kMessageUserReceiveKey];
    [query setCachePolicy:kPFCachePolicyCacheThenNetwork];
    
    [query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
        if (!error) {
            self.messagesDataArray = [NSMutableArray new];
            if (objects.count > 0) {
                [self.messagesDataArray addObject:objects[0]];
                for (int i = 1; i < objects.count; i++) {
                    PFObject *messageChat = [objects objectAtIndex:i];
                    if (![self isExistWithMessageChat:messageChat]){
                        [self.messagesDataArray addObject:messageChat];
                    }
                }
                [self.tableView reloadData];
            }
        }
        else {
            NSLog(@"Error: %@ %@", error, [error userInfo]);
        }
    }];
}