Swift - Get all records from Cloudkit Public Database - ios

Question

Hi i'm trying to fetch all records from my publicDB in cloudkit, and currently there are more of 2000 records. How can I fetch them all and put them in an array?
I've tryed these two methods without success. Can you please help me?
1 Approach
let predicate = NSPredicate(value: true)
let query = CKQuery(recordType: "Position", predicate: predicate)
query.sortDescriptors = [NSSortDescriptor(key: "creationDate", ascending: false)]
publicDB.perform(query, inZoneWith: nil) { (results, error) -> Void in
if error != nil {
DispatchQueue.main.async(execute: { () -> Void in
self.delegate?.errorUpdating(error: error! as NSError)
return
})
} else {
self.positionArray.removeAll(keepingCapacity: true)
for record in results! {
let position = Position(record: record as CKRecord, database: self.publicDB)
self.positionArray.append(position)
}
}
DispatchQueue.main.async(execute: { () -> Void in
/* my elaboration with the complete result */
})
}
2 Approach
let predicate = NSPredicate(value: true)
let query = CKQuery(recordType: "Position", predicate: predicate)
query.sortDescriptors = [NSSortDescriptor(key: "creationDate", ascending: false)]
let qop = CKQueryOperation(query: query)
qop.resultsLimit = 3000
qop.recordFetchedBlock = { (record: CKRecord) in
let position = Position(record: record, database: self.publicDB)
self.positionArray.append(position)
print(self.positionArray.count)
}
qop.queryCompletionBlock = { (cursor: CKQueryOperation.Cursor?, error: Error?) in
DispatchQueue.main.async(execute: { () -> Void in
if let cursor = cursor {
print("entro")
let newOperation = CKQueryOperation(cursor: cursor)
newOperation.recordFetchedBlock = qop.recordFetchedBlock
newOperation.queryCompletionBlock = qop.queryCompletionBlock
self.publicDB.add(newOperation)
}
else if let error = error {
print("Error:", error)
}
// No error and no cursor means the operation was successful
else {
print("Finished with records:", self.positionArray)
if(!all){
// my elaboration
}
else{
// my elaboration
}
}
})
}
self.publicDB.add(qop)
With the first approach I can fetch at most 100 records.
With the second approach I can fetch at most 400 records.
But i need to fill my array with the all over 2000 records, how can achieve the result?

Answer 1

Plese, Try this one!
var Whistle = [CKRecord] ()
func loadWhistles(completionHandler: (() -> Void)?) {
let pred = NSPredicate(value: true)
let sort = NSSortDescriptor(key: nomeDaTabela, ascending: ordemDaTabela)
let query = CKQuery(recordType: "Cliente", predicate: pred)
query.sortDescriptors = [sort]
let operation = CKQueryOperation(query: query)
operation.desiredKeys = ["Name"]
operation.resultsLimit = 2000
var newWhistles = Whistle
operation.recordFetchedBlock = { record in
newWhistles.append(record)
}
operation.queryCompletionBlock = { [unowned self] (cursor, error) in
DispatchQueue.main.async {
if error == nil {
//ViewController.isDirty = false
self.clienteRecords = newWhistles
self.clientesTableView.reloadData()
} else {
let ac = UIAlertController(title: "Fetch failed", message: "There was a problem fetching the list of whistles; please try again: \(error!.localizedDescription)", preferredStyle: .alert)
ac.addAction(UIAlertAction(title: "OK", style: .default))
self.present(ac, animated: true)
}
}
}
PublicDatabase.add(operation)
completionHandler?()
}

Answer 2

There is indeed a limit of 400 records per fetch operation, so you need to check CKQueryCursor value returned by query completion block, and if it is not nil start another operation with it CKQueryOperation(cursor: cursor).
So in principle your 2nd approach is correct. My guess is that your problem occurs due to threading issue, try removing DispatchQueue.main.async(execute: { () -> Void in.
P.S. Check out how it is done in RxCloudKit (which handles big fetches automatically), it definitely works for fetching 1000+ records - RecordFetcher.queryCompletionBlock(cursor: CKQueryCursor?, error: Error?)