How to prevent duplicate entry on parse? - ios

Question

I' trying to save song info to parse, but if the song already exist in parse I want my code just do nothing.
I've tried this code below:
var Music = PFObject(className:"Musics")
var query = PFQuery(className:"Musics")
query.findObjectsInBackgroundWithBlock {
(objects: [AnyObject]?, error: NSError?) -> Void in
if error == nil {
// The find succeeded.
println("Successfully retrieved \(objects!.count) scores.")
// Do something with the found objects
if let objects = objects as? [PFObject] {
for object in objects {
var songTitle = object.objectForKey("songTitle") as? String
if songTitle != title {
Music["createdBy"] = PFUser.currentUser()
Music["songTitle"] = title
Music["albumCover"] = imageFile
Music["songArtist"] = artist
Music.saveInBackgroundWithBlock {
(success: Bool, error: NSError?) -> Void in
if (success) {
println("succeed")
} else {
// There was a problem, check error.description
println("error jeh")
}
}
}else{
println("song already exist")
}
}
}
} else {
// Log details of the failure
println("Error: \(error!) \(error!.userInfo!)")
}
}
the code above give below result on log:
Successfully retrieved 4 scores.
song already exist
Successfully retrieved 4 scores.
song already exist
Successfully retrieved 4 scores.
song already exist
Successfully retrieved 4 scores.
song already exist
succeed
succeed
succeed
succeed
succeed
succeed
succeed
succeed
succeed
succeed
succeed
succeed
Why my for loop , looping more than the Objects.count? and how can I prevent dupiclate entry on parse?
give me any advice, doesn't matter in obj c or swift

Answer 1

I suggest to implement a simple beforeSave trigger, on Parse Cloud code, in order to check if the new entry song already exist (basically you're going to make one or more field uniques. For example:
Parse.Cloud.beforeSave("Musics", function(request, response) {
var newEntrySong = request.object;
var querySongs = new Parse.Query("Musics");
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();
}
});
});
Hope it helps.