Why is it in an infinite loop? - ios

Question

I am trying to capture the data from a json page, and store it in a database. I can currently get the artist and title from the json page. I am filling a array in my program with the values captured from data to avoid repeats. When run the for loop and get the values and put them in the Parsearray, an infinite loop starts. It does not end, a it's always being called. I know this because i see "called" being printed in the console multiple times and it does not stop. How do I fix this?
override func viewWillAppear(animated: Bool) {
super.viewWillAppear(animated);
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)
print("called")
}
})
self.getSpotify()
}
func getSpotify(){
let searchTerm = "tgirish10"
var endpoint = NSURL(string: "<api URL>")
var data = NSData(contentsOfURL: endpoint!)
let task = NSURLSession.sharedSession().dataTaskWithURL(endpoint!) {(data, response, error) -> Void in
do {
if let jsonData = data,
let dict = try NSJSONSerialization.JSONObjectWithData(jsonData, options: []) as? NSDictionary,
let recent = dict["recenttracks"] as? NSDictionary,
let items = recent["track"] as? NSArray {
for item in items {
if let spotifytitle = item["name"] as? String {
print("title: \(spotifytitle)")
if let spotifyartist = item["artist"]!!["#text"] as? String{
print("artist: \(spotifyartist)")
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)
print("called")
}
if self.Parsearray.contains(spotifytitle){
print("already in db")
}else{
let objectPointer = PFObject(className: "Pointer")
objectPointer["title"] = spotifytitle
objectPointer["user"] = PFUser.currentUser()
objectPointer["artist"] = spotifyartist
objectPointer.saveInBackgroundWithBlock({ (success: Bool, error: NSError?) -> Void in
if(error != nil){
print(error)
}else{
print("saved")
}
})
}
})
}
}
}
}
} catch let jsonError as NSError {
print(jsonError)
}
}
task.resume()
}

Answer 1

Beyond the issues in the comments above, the main problem is that your code does the following:
get some data from Spotify
for each track, get all Pointer objects from Parse
for each of those objects, add title to parseArray (so after a while, the list will contain multiple copies of all titles)
then check if title of the track is in this list
So the loop does not seem to be infinite, but you are unnecessarily adding a lot of data.
Two options:
move the loading of the titles outside of the loop on tracks
or use a PFQuery which only returns Pointer objects which match, and just check if the returned list is empty or not