Challenging Online Database Persistence w/ Core Data? - ios

Question

This is my first time doing any work with database persistence/maintenance online, so I apologize in advance for my sloppy code. My app consists of the user creating a bunch of athletes and having their data save online so they can be accessed from any device. This works fantastically, except the athletes each get saved twice online, and it's making me want to rip my hair out. I've checked my code several hundred times, but I just can't seem to find why athletes are being saved twice on the server, resulting in 2 locally as well. I'm utilizing the Parse.com framework. Am I missing something?
The following method gets called from a pull down to refresh on a table view controller.
- (void)getParseData {
NSLog(#"GET PARSE DATA WAS CALLED");
if(self.syncing != TRUE){
NSLog(#"GET PARSE DATA RAN");
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
dateFormatter.dateStyle = NSDateFormatterLongStyle;
PFQuery *query = [PFQuery queryWithClassName:#"Athlete"];
[self populateAthleteArray];
if (self.athleteArray.count == 0) {
NSLog(#"ATHLETE ARRAY IS EMPTY");
// If the athlete array has no objects, download all objects from the database.
[query findObjectsInBackgroundWithBlock: ^(NSArray *objects, NSError *error) {
self.syncing = TRUE;
if (!error) {
self.syncing = FALSE;
for (PFObject * object in objects) {
Athlete *newAthlete = [NSEntityDescription insertNewObjectForEntityForName:#"Athlete" inManagedObjectContext:_managedObjectContext];
newAthlete.first = object[#"first"];
newAthlete.last = object[#"last"];
newAthlete.updatedAt = [dateFormatter stringFromDate:[object updatedAt]];
newAthlete.objectId = [object objectId];
[_managedObjectContext save:nil];
}
self.syncing = FALSE;
}
else {
self.syncing = FALSE;
NSLog(#"Error: %# %#", error, [error userInfo]);
}
if(self.needToUploadArray.count > 0){
[PFObject saveAllInBackground:self.needToUploadArray target:nil selector:#selector(emptyUploadArray)];
}
}];
[self populateAthleteArray];
[self.tableView reloadData];
}
else {
NSLog(#"ATHLETE ARRAY HAS ATHLETES ALREADY");
// Athlete array has athletes already
NSMutableArray *athletesToUpload = [NSMutableArray array];
// Placeholder array for athletes that aren't in the database.
for (Athlete *athlete in athleteArray) {
if (athlete.objectId.length == 0 || athlete.objectId == nil) {
// If the objectId is nil, it wasn't uploaded to the database. Add to placeholder array.
[athletesToUpload addObject:athlete];
}
}
[query findObjectsInBackgroundWithBlock: ^(NSArray *objects, NSError *error) {
self.syncing = TRUE;
if (!error) {
// Downloaded all athletes successfully
self.syncing = FALSE;
BOOL found = FALSE;
[self populateAthleteArray];
NSMutableArray *athletesToDelete = [NSMutableArray array];
for (Athlete * athlete in athleteArray) {
for (PFObject * object in objects) {
// Check to see each local athlete exists in the online database
if ([object.objectId isEqualToString:athlete.objectId]) {
// Athlete was find in the online database
found = TRUE;
break;
}
}
if (found != TRUE) {
NSLog(#"%# was not found online.",athlete.first);
if(athlete.objectId.length > 0){
NSLog(#"%# was deleted online. delete them locally",athlete.first);
[athletesToDelete addObject:athlete];
}
else{
// No athlete in the local database matched any of the athletes online
PFObject *onlineAthlete = [PFObject objectWithClassName:#"Athlete"];
onlineAthlete[#"first"] = athlete.first;
onlineAthlete[#"last"] = athlete.last;
PFFile *imageFile = [PFFile fileWithName:[NSString stringWithFormat:#"%#%#MedicalRelease.jpg", athlete.first, athlete.last] data:athlete.medical_release_image];
onlineAthlete[#"medical_release_image"] = imageFile;
[onlineAthlete saveInBackgroundWithBlock: ^(BOOL succeeded, NSError *error) {
self.syncing = TRUE;
if (succeeded) {
NSLog(#"SAVED SUCCESSFULLY");
self.syncing = FALSE;
PFQuery *query = [PFQuery queryWithClassName:#"Athlete"];
[query orderByDescending:#"createdAt"];
[query getFirstObjectInBackgroundWithBlock: ^(PFObject *object, NSError *error) {
Athlete *athleteToChange = [self findAthlete:athlete.objectId];
[athleteToChange setObjectId:[object objectId]];
[_managedObjectContext save:nil];
}];
}
}];
}
}
found = FALSE;
}
if(athletesToDelete.count > 0){
for(id athlete in athletesToDelete){
NSManagedObject *eventToDelete = athlete;
[_managedObjectContext deleteObject:eventToDelete];
[athleteArray removeObjectAtIndex:[athleteArray indexOfObject:athlete]];
[self.tableView reloadData];
NSError *error = nil;
if (![_managedObjectContext save:&error]) {
NSLog(#"there is an error: %#", error);
}
}
}
for (PFObject *object in objects) {
// Loop through every athlete downloaded
for (Athlete * athlete in athleteArray) {
// For every object downloaded, compare it to every athlete in the local database.
if ([object.objectId isEqualToString:athlete.objectId]) {
// If the object's id matches the local athletes id, we found the object
if ([object updatedAt] >= [dateFormatter dateFromString:athlete.updatedAt]) {
// If the object has been updated more recently than the athlete, update the local athlete
Athlete *sameAthlete = [self findAthlete:athlete.objectId];
sameAthlete.first = object[#"first"];
sameAthlete.last = object[#"last"];
sameAthlete.updatedAt = [dateFormatter stringFromDate:[object updatedAt]];
sameAthlete.address = object[#"address"];
sameAthlete.objectId = [object objectId];
[_managedObjectContext save:nil];
}
found = TRUE;
// The athlete was found in the database
break;
}
}
if (found != TRUE) {
// We looped through all the local athletes, the object downloaded isn't in the local database; add them.
Athlete *athlete = [NSEntityDescription insertNewObjectForEntityForName:#"Athlete" inManagedObjectContext:_managedObjectContext];
athlete.first = object[#"first"];
athlete.last = object[#"last"];
athlete.objectId = [object objectId];
athlete.address = object[#"address"];
athlete.updatedAt = [dateFormatter stringFromDate:[object updatedAt]];
[_managedObjectContext save:nil];
}
// Reset flag var
found = FALSE;
}
}
else {
self.syncing = FALSE;
NSLog(#"Error: %# %#", error, [error userInfo]);
}
self.syncing = FALSE;
}];
if (athletesToUpload.count > 0) {
for (Athlete *athlete in athletesToUpload) {
PFObject *upload = [PFObject objectWithClassName:#"Athlete"];
upload[#"first"] = athlete.first;
upload[#"last"] = athlete.last;
PFFile *imageFile = [PFFile fileWithName:[NSString stringWithFormat:#"%#%#MedicalRelease.jpg", athlete.first, athlete.last] data:athlete.medical_release_image];
upload[#"medical_release_image"] = imageFile;
[upload saveInBackgroundWithBlock: ^(BOOL succeeded, NSError *error) {
if (succeeded) {
PFQuery *uploadQuery = [PFQuery queryWithClassName:#"Athlete"];
[uploadQuery orderByDescending:#"createdAt"];
[uploadQuery getFirstObjectInBackgroundWithBlock: ^(PFObject *object, NSError *error) {
[athlete setObjectId:[object objectId]];
}];
}
}];
}
}
[self populateAthleteArray];
[self.tableView reloadData];
}
}
}

Answer 1

In the branch marked by the comment // No athlete in the local database matched any of the athletes online you are creating a new PFObject and saving it to Parse. In my understanding, this should not be correct, since the athlete is not in the local db but online.