CKQueryOperation queryCompletionBlock return a nil cursor - ios

Question

I'm fetching a CloudKit database with CKQueryOperation. For some reason every time when I press a fetch button, the first time I get a nil cursor. The second time it fetches and gets data, it's all good. When I check the recordFetchedBlock it does get the results and appends them, but at the end the array is empty. I don't understand why this happens. I want to show the results immediately since they have been fetched. I think the problem is with the nil cursor, but I'm open for other suggestions. Here's my code:
public class CloudKitDatabase {
static let shared = CloudKitDatabase()
var records = [CKRecord]()
let publicData = CKContainer.default().publicCloudDatabase
init() {
self.fetchRecords()
}
func fetchRecords() {
let predicate = NSPredicate(value: true)
let query = CKQuery(recordType: "OECD", predicate: predicate)
let queryOperation = CKQueryOperation(query: query)
queryOperation.recordFetchedBlock = {
record in
self.records.append(record)
}
queryOperation.queryCompletionBlock = { cursor, error in
DispatchQueue.main.async {
if error != nil {
print(error.debugDescription)
} else {
if cursor != nil {
self.queryServer(cursor!)
} else {
print("CURSOR IS NIL")
}
}
}
}
self.publicData.add(queryOperation)
}
func queryServer(_ cursor: CKQueryOperation.Cursor) {
let queryOperation = CKQueryOperation(cursor: cursor)
queryOperation.recordFetchedBlock = {
record in
self.records.append(record)
}
queryOperation.queryCompletionBlock = { cursor, error in
DispatchQueue.main.async {
if error != nil {
print(error.debugDescription)
} else {
if cursor != nil {
self.queryServer(cursor!)
} else {
print("CURSOR IS NIL")
}
}
}
}
self.publicData.add(queryOperation)
}
The Debug area tells me that:
CURSOR IS NIL
and CloudKitDatabase.shared.records.isEmpty is true

Answer 1

First try some configs on the first query;
let queryOperation = CKQueryOperation(query: query)
queryOperation.queuePriority = .veryHigh
queryOperation.resultsLimit = 99 // built in limit is 400
Next, don't do the cursor calls in a dispatch and include your completions;
queryOperation.queryCompletionBlock =
{ cursor, error in
if error != nil {
print(error.debugDescription)
} else {
if cursor != nil {
self.queryServer(cursor!)
} else {
print("CURSOR IS NIL")
completion(nil)
}
}
}
and;
queryOperation.queryCompletionBlock =
{ cursor, error in
if error != nil {
print(error.debugDescription)
} else {
if cursor != nil {
self.queryServer(cursor!)
} else {
print("CURSOR IS NIL")
completion(nil)
}
}
}
also don't forget to empty your records array at the beginning of fetchRecords otherwise successive calls will get the same records in the array.