Swift CloudKit SaveRecord "Error saving record"

Question

I am trying to save a record to CloudKit but am getting an error. I had seen elsewhere that this was an issue that required knowing how to save but I can't get this to work.

    var database:CKDatabase = CKContainer.defaultContainer().publicCloudDatabase
    var aRecord:CKRecord!

    if self.cloudId == nil {
        var recordId:CKRecordID = CKRecordID(recordName: "RecordId")
        self.cloudId = recordId // Setup at top
    }

    aRecord = CKRecord(recordType: "RecordType", recordID: self.cloudId)
    aRecord.setObject(self.localId, forKey: "localId")

    // Set the normal names etc
    aRecord.setObject(self.name, forKey: "name")

    var ops:CKModifyRecordsOperation = CKModifyRecordsOperation()
    ops.savePolicy = CKRecordSavePolicy.IfServerRecordUnchanged

    database.addOperation(ops)
    database.saveRecord(aRecord, completionHandler: { (record, error) in

        if error != nil {
            println("There was an error \(error.description)!")

        } else {
            var theRecord:CKRecord = record as CKRecord
            self.cloudId = theRecord.recordID
        }
    })

This gives me the error:

There was an error <CKError 0x16d963e0: "Server Record Changed" (14/2017); "Error saving record <CKRecordID: 0x15651730; xxxxxx:(_defaultZone:__defaultOwner__)> to server: (null)"; uuid = 369226C6-3FAF-418D-A346-49071D3DD70A; container ID = "iCloud.com.xxxxx.xxxx-2">!

Not sure, given that I have added CKModifyRecordsOperation. Sadly there is no examples within Apple's documentation. I miss that (which you get on MSDN).

Thanks peeps!

Answer 1

A record can be saved to iCloud using CKDatabase's convenience method saveRecord: or via a CKModifyRecordsOperation. If it's a single record, you can use saveRecord: but will need to fetch the record you'd like to modify using fetchRecordWithID: prior to saving it back to iCloud. Otherwise, it will only let you save a record with a new RecordID. More here.

database.fetchRecordWithID(recordId, completionHandler: { record, error in
    if let fetchError = error {
            println("An error occurred in \(fetchError)")
        } else {
            // Modify the record
            record.setObject(newName, forKey: "name")
        } 
}


database.saveRecord(aRecord, completionHandler: { record, error in
    if let saveError = error {
            println("An error occurred in \(saveError)")
        } else {
            // Saved record
        } 
}

The code above is only directionally correct but won't work as is because by the time the completionHandler of fetchRecordWithID returns, saveRecord will have fired already. A simple solution would be to nest saveRecord in the completionHandler of fetchRecordWithID. A probably better solution would be to wrap each call in a NSBlockOperation and add them to an NSOperationQueue with saveOperation dependent on fetchOperation.

This part of your code would be for a CKModifyRecordsOperation and not needed in case you are only updating a single record:

var ops:CKModifyRecordsOperation = CKModifyRecordsOperation()
ops.savePolicy = CKRecordSavePolicy.IfServerRecordUnchanged
database.addOperation(ops)

If you do use a CKModifyRecordsOperation instead, you'll also need to set at least one completion block and deal with errors when conflicts are detected with existing records:

let saveRecordsOperation = CKModifyRecordsOperation()

var ckRecordsArray = [CKRecord]()
// set values to ckRecordsArray

saveRecordsOperation.recordsToSave = ckRecordsArray
saveRecordsOperation.savePolicy = .IfServerRecordUnchanged
saveRecordsOperation.perRecordCompletionBlock { record, error in
    // deal with conflicts
    // set completionHandler of wrapper operation if it's the case
}

saveRecordsOperation.modifyRecordsCompletionBlock { savedRecords, deletedRecordIDs, error in
    // deal with conflicts
    // set completionHandler of wrapper operation if it's the case
}

database.addOperation(saveRecordsOperation)

There isn't much sample code yet besides the CloudKitAtlas demo app, which is in Objective-C. Hope this helps.