How to update data on cloudKit without creating a new record? - swift

Question

Here is what I am trying to do. I have a simple journaling app with two views: a tableView that lists the titles of the entries and a viewController that has a text field for a title, and a textView for the text body (and a save button to save to cloudKit). On the viewController, I hit save and the record is saved to cloudKit and also added to the tableView successfully. This is all good.
I want to be able to edit/update the journal entry. But when I go back into the journal entry, change it in any way, then hit save again, the app returns to the tableView controller with an updated entry, but cloudKit creates a NEW entry separate from the one I wanted to edit. Then when I reload the app, my fetchRecords function fetches any extra records cloudKit has created.
Question: How do I edit/update an existing journal entry without creating a new entry in cloudKit?
Let me know if you need something else to further clarify my question.
Thanks!
Here are my cloudKit functions:
import Foundation
import CloudKit
class CloudKitManager {
let privateDB = CKContainer.default().publicCloudDatabase //Since this is a journaling app, we'll make it private.
func fetchRecordsWith(type: String, completion: #escaping ((_ records: [CKRecord]?, _ error: Error?) -> Void)) {
let predicate = NSPredicate(value: true) // Like saying I want everything returned to me with the recordType: type. This isn't a good idea if you have a massive app like instagram because you don't want all posts ever made to be loaded, just some from that day and from your friends or something.
let query = CKQuery(recordType: type, predicate: predicate)
privateDB.perform(query, inZoneWith: nil, completionHandler: completion) //Allows us to handle the completion in the EntryController to maintain proper MVC.
}
func save(records: [CKRecord], perRecordCompletion: ((_ record: CKRecord?, _ error: Error?) -> Void)?, completion: ((_ records: [CKRecord]?, _ error: Error?) -> Void)?) {
modify(records: records, perRecordCompletion: perRecordCompletion, completion: completion )
}
func modify(records: [CKRecord], perRecordCompletion: ((_ record: CKRecord?, _ error: Error?) -> Void)?, completion: ((_ records: [CKRecord]?, _ error: Error?) -> Void)?) {
let operation = CKModifyRecordsOperation(recordsToSave: records, recordIDsToDelete: nil)
operation.savePolicy = .ifServerRecordUnchanged //This is what updates certain changes within a record.
operation.queuePriority = .high
operation.qualityOfService = .userInteractive
operation.perRecordCompletionBlock = perRecordCompletion
operation.modifyRecordsCompletionBlock = { (records, _, error) in
completion?(records, error)
}
privateDB.add(operation) //This is what actually saves your data to the database on cloudkit. When there is an operation, you need to add it.
}
}
This is my model controller where my cloudKit functions are being used:
import Foundation
import CloudKit
let entriesWereSetNotification = Notification.Name("entriesWereSet")
class EntryController {
private static let EntriesKey = "entries"
static let shared = EntryController()
let cloudKitManager = CloudKitManager()
init() {
loadFromPersistentStorage()
}
func addEntryWith(title: String, text: String) {
let entry = Entry(title: title, text: text)
entries.append(entry)
saveToPersistentStorage()
}
func remove(entry: Entry) {
if let entryIndex = entries.index(of: entry) {
entries.remove(at: entryIndex)
}
saveToPersistentStorage()
}
func update(entry: Entry, with title: String, text: String) {
entry.title = title
entry.text = text
saveToPersistentStorage()
}
// MARK: Private
private func loadFromPersistentStorage() {
cloudKitManager.fetchRecordsWith(type: Entry.TypeKey) { (records, error) in
if let error = error {
print(error.localizedDescription)
}
guard let records = records else { return } //Make sure there are records.
let entries = records.flatMap({Entry(cloudKitRecord: $0)})
self.entries = entries //This is connected to the private(set) property "entries"
}
}
private func saveToPersistentStorage() {
let entryRecords = self.entries.map({$0.cloudKitRecord})
cloudKitManager.save(records: entryRecords, perRecordCompletion: nil) { (records, error) in
if error != nil {
print(error?.localizedDescription as Any)
return
} else {
print("Successfully saved records to cloudKit")
}
}
}
// MARK: Properties
private(set) var entries = [Entry]() {
didSet {
DispatchQueue.main.async {
NotificationCenter.default.post(name: entriesWereSetNotification, object: nil)
}
}
}
}

Answer 1

Here's a couple threads that might be helpful.
If you were caching the data locally you would use the encodesystemfields method to create a new CKRecord that will update an existing one on the server.
How (and when) do I use iCloud's encodeSystemFields method on CKRecord?
It doesn't appear you are caching locally. I don't have experience doing it without using encodesystemfields, but it looks like you have to pull the record down and save it back in the completion handler of the convenience method:
Trying to modify ckrecord in swift