How do I implement the cloud code? - ios

Question

I am very new to cloud code, and I am having trouble. I have already referred to this How to prevent duplicate entry on parse? and I am trying to do the same exact thing. I am trying to prevent a duplicate entry in my class. I keep getting the error in the cloud code "Song already exists" even though the class is empty.
This is the cloud code. I am confused on what the querySongs.equalTo("title", newEntrySong.get("title")); is doing. Is it looking for the actual word title? becuase I need it to find a specific title.
Parse.Cloud.beforeSave("Pointer", function(request, response) {
var newEntrySong = request.object;
var querySongs = new Parse.Query("Pointer");
querySongs.equalTo("title", newEntrySong.get("title"));
//querySongs.equalTo("description", newEntrySong.get("description"));
// this could be a sort of signature for your song, to make more unique (skipping spaces and new lines for example)
// querySongs.equalTo("md5Title", newEntrySong.get("md5Title"));
querySongs.first({
success: function(temp) {
response.error({errorCode:123,errorMsg:"Song already exist!"});
},
error: function(error) {
response.success();
}
});
});
Below is my code for finding duplicates in the class, but it doesn't work well. Do I need to replace the whole thing? or get rid of it? since I have the cloud code
func getNowPlayingItem() {
print("entered function")
NSNotificationCenter.defaultCenter().removeObserver(self)
if let nowPlaying = musicPlayer.nowPlayingItem {
let title = nowPlaying[MPMediaItemPropertyTitle] as? String
let artisttest = nowPlaying[MPMediaItemPropertyTitle]
if let artist = nowPlaying[MPMediaItemPropertyArtist] as? String{
let objectPointer = PFObject(className: "Pointer")
let object = PFObject(className: "MasterSongs")
let query = PFQuery(className: "Pointer")
query.findObjectsInBackgroundWithBlock({
(objects: [AnyObject]?, error: NSError?) -> Void in
var objectIDs = objects as! [PFObject]
for i in 0...objectIDs.count-1{
self.Parsearray.append((objectIDs[i].valueForKey("title") as? String)!)
}
if self.Parsearray.contains(title!){
print("already in db")
NSNotificationCenter.defaultCenter().addObserver(self, selector: "getNowPlayingItem", name: MPMusicPlayerControllerNowPlayingItemDidChangeNotification, object: nil)
}else{
objectPointer["title"] = title
objectPointer["user"] = PFUser.currentUser()
objectPointer["artist"] = artist
print("about to save with artist")
objectPointer.saveInBackgroundWithBlock({ (success: Bool, error: NSError?) -> Void in
if(error != nil){
print(error)
}else{
NSNotificationCenter.defaultCenter().addObserver(self, selector: "getNowPlayingItem", name: MPMusicPlayerControllerNowPlayingItemDidChangeNotification, object: nil)
print("saved")
}
})
}
})
}else{
let objectPointer = PFObject(className: "Pointer")
let query = PFQuery(className: "Pointer")
query.findObjectsInBackgroundWithBlock({
(objects: [AnyObject]?, error: NSError?) -> Void in
var objectIDs = objects as! [PFObject]
for i in 0...objectIDs.count-1{
self.Parsearray.append((objectIDs[i].valueForKey("title") as? String)!)
// print(self.Parsearray)
}
if self.Parsearray.contains(title!){
print("already in db with no artist")
NSNotificationCenter.defaultCenter().addObserver(self, selector: "getNowPlayingItem", name: MPMusicPlayerControllerNowPlayingItemDidChangeNotification, object: nil)
}else{
objectPointer["title"] = title
objectPointer["user"] = PFUser.currentUser()
objectPointer["artist"] = "No artist found :("
print("about to save")
objectPointer.saveInBackgroundWithBlock({ (success: Bool, error: NSError?) -> Void in
if(error != nil){
print(error)
}else{
NSNotificationCenter.defaultCenter().addObserver(self, selector: "getNowPlayingItem", name: MPMusicPlayerControllerNowPlayingItemDidChangeNotification, object: nil)
print("saved")
}
})
}
})
}
}
}

Answer 1

The OP's beforeSave function fails to check whether or not the query identified a duplicate. As written, it always reports a duplicate, but can be fixed simply...
var newEntrySong = request.object;
var querySongs = new Parse.Query("Pointer");
querySongs.equalTo("title", newEntrySong.get("title"));
// whatever else you want to do that defines a duplicate
querySongs.first().then(function(result) {
// this is the check the code was missing
if (result) {
response.error({errorCode:123,errorMsg:"Song already exist!"});
} else {
response.success();
}
}, function(error) {
response.error(error);
})
If you have this working to prevent duplicates, there's no need for the client code to do the same.