cloudkit tips and tricks - apple developer · cloudkit tips and tricks system frameworks session...

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#WWDC15

CloudKit Tips And Tricks

System Frameworks

Session 715

Nihar Sharma CloudKit Engineer

CloudKitWhat is it?

CloudKitWhat is it?

iCloud database

CloudKitWhat is it?

iCloud databaseLarge file storage

CloudKitWhat is it?

iCloud databaseLarge file storagePrivacy obsessed

CloudKitWhat is it?

iCloud databaseLarge file storagePrivacy obsessedDeveloper API

CloudKitWhat is it?

iCloud databaseLarge file storagePrivacy obsessedDeveloper APIApple applications built on it

CloudKitOne year later

CloudKitNo really, what is it?

Introduction to CloudKit WWDC14

Advanced CloudKit WWDC14

100%Awesome with Swift 2!

record.setObject(5, forKey: "numberOfClowns")if let partyDate = record.objectForKey("date") as? NSDate {…}

record["numberOfClowns"] = 5 if let partyDate = record["date"] as? NSDate {…}


modifyRecordsOperation.recordsToSave = ["I’m not a CKRecord!"]


modifyRecordsOperation.recordsToSave = ["I’m not a CKRecord!"]error: cannot assign a value of type '[String]' to a value of type '[CKRecord]?'

CloudKitStorage architecture

CloudKit Container


CloudKit Container


Public Database

CloudKit Container

Private Database


Public Database

CloudKit Container

Private Database


Public DatabaseDefault Zone

RecordRecordRecordRecordRecord

CloudKit Container

Private Database


Public DatabaseDefault Zone Default Zone

RecordRecordRecordRecordRecordRecordRecordRecordRecordRecord

CloudKit Container

Private DatabaseCustom Zone


Public DatabaseDefault Zone Default Zone

RecordRecordRecordRecordRecordRecordRecordRecordRecordRecord

Custom ZoneCustom Zone

RecordRecordRecordRecordRecord

What We’ll Cover TodayClown storage app

What We’ll Cover TodayClown storage app

Party

Party

Clown

Clown

Clown

Public Database

ClownCentralOur best fake clown app yet

Accounts New

Jimmy Reviewed Nihar’s Party

We’re blowing up balloons and icing the cake! There’s a big birthday party that we hope you can make! We’re not clowning around so circle the date for Nihar’s Party.

News Parties Photos Reviews

Susan Reviewed Nihar’s Party

Dan Reviewed Nihar’s Party

Alice Hosted her 6th Party!

John Hosted His 3rd Party!

Nihar Hosted His 10th Party!

What We’ll Cover TodayCloudKit tips and tricks


Error handling


Error handlingLocal cache


Error handlingLocal cacheSubscriptions


Error handlingLocal cacheSubscriptionsPerformance

Error Handling with CloudKitAs important as any feature!

Account Status

Account Status

ClownCentral requires iCloud account

Account Status

ClownCentral requires iCloud accountPrivate database access

Account Status

ClownCentral requires iCloud accountPrivate database accessPublic database write access

Account Status

ClownCentral requires iCloud accountPrivate database accessPublic database write accesscontainer.accountStatusWithCompletionHandler { accountStatus, error in…}

Account Status

Account Status

CKErrorNotAuthenticated

Account Status


Check account status

Account Status


Check account status• CKAccountStatusNoAccount

Account Status



CKAccountChangedNotification

Account Status




Accounts New









Account Status




Accounts New









ClownCentral

Please sign into an iCloud account.

OK

Account Status




Accounts New









Retrying Operations

Retrying Operations

Poor network conditions• CKErrorNetworkFailure

Retrying Operations

Poor network conditions• CKErrorNetworkFailure

Busy servers• CKErrorServiceUnavailable • CKErrorZoneBusy

Retrying Operations

Retrying Operations

CKErrorRetryAfterKeyif let retryAfterValue = error.userInfo[CKErrorRetryAfterKey] as? Double { let retryAfterDate = NSDate(timeIntervalSinceNow: retryAfterValue)}

Rate Limiting

Rate Limiting

CKErrorRequestRateLimited

Rate Limiting


Mitigates application bugs

Rate Limiting


Mitigates application bugsClient-side throttle

Rate Limiting


Mitigates application bugsClient-side throttleCKErrorRetryAfterKey

Handling Conflicts

Handling Conflicts

Attendees[]

Party

Handling Conflicts

Attendees[]

Party

Attendee

Attendee

Attendee

Handling Conflicts

Attendees[]

WWDC Bash

A

Handling Conflicts

Attendees[]

WWDC Bash

A

Attendees[]

WWDC Bash

A Attendees[]

WWDC Bash

A

Handling Conflicts

Attendees[]

WWDC Bash

John

Attendee

A

Attendees[]

WWDC Bash

Attendees[]

WWDC Bash

A

B

B

John

Attendee

Handling Conflicts

Attendees[]

WWDC Bash

John

Attendee

Alice

Attendee

A

Attendees[]

WWDC Bash

Attendees[]

WWDC Bash

A B

B

John

Attendee

Handling Conflicts

Handling Conflicts

CKErrorServerRecordChanged

Handling Conflicts


if let serverRecord = error.userInfo[CKRecordChangedErrorServerRecordKey] as? CKRecord {}

Handling Conflicts


if let serverRecord = error.userInfo[CKRecordChangedErrorServerRecordKey] as? CKRecord {}

Attendees[]

WWDC Bash

B John

Attendee

Handling Conflicts

Key Record

ServerRecordKey Attendees[]

WWDC Bash

B John

Attendeee

Handling Conflicts

Key Record

ServerRecordKey

AncestorRecordKey

Attendees[]

WWDC Bash

B John

Attendeee

Handling Conflicts

Key Record

ServerRecordKey

AncestorRecordKey

Attendees[]

WWDC Bash

B John

Attendeee

Attendees[]

WWDC Bash

A

Handling Conflicts

Key Record

ServerRecordKey

AncestorRecordKey

ClientRecordKey

Attendees[]

WWDC Bash

B John

Attendeee

Attendees[]

WWDC Bash

A

Handling Conflicts

Key Record

ServerRecordKey

AncestorRecordKey

ClientRecordKey

Attendees[]

WWDC Bash

B John

Attendeee

Attendees[]

WWDC Bash

A

Attendees[]

WWDC Bash

A Alice

Attendee

Handling Conflicts

Key Record

ServerRecordKey Attendees[]

WWDC Bash

B John

Attendeee

Handling Conflicts

Key Record

ServerRecordKey

Attendees[]

WWDC Bash

B John

Attendeee

Attendees[]

WWDC Bash

B John

Attendeee

Handling Conflicts

Key Record

ServerRecordKey

Alice

Attendee

Attendees[]

WWDC Bash

B John

Attendeee

Attendees[]

WWDC Bash

B John

Attendeee

Handling Conflicts

Attendees[]

Party

Attendee

Attendee

Attendee

CloudKit Operations

Batch Operations

Party

Batch Operations

Party

Photo

Photo

Photo

Batch OperationsConvenience API Counterpart

extension CKDatabase { func saveRecord(record: CKRecord, completionHandler: (CKRecord?, NSError?) -> Void) … }

Convenience API

iOS

iCloudAccounts New


Convenience API

iOS

iCloud

saveRecord:…

Accounts New


Convenience API

iOS

iCloud

saveRecord:…saveRecord:…saveRecord:…saveRecord:…saveRecord:…saveRecord:…

Accounts New


Batch OperationsCKOperation recap

extension CKDatabase { func saveRecord(record: CKRecord, completionHandler: (CKRecord?, NSError?) -> Void)…}

Batch OperationsCKOperation recap

extension CKDatabase { func saveRecord(record: CKRecord, completionHandler: (CKRecord?, NSError?) -> Void)…}

class CKModifyRecordsOperation : CKDatabaseOperation { init() convenience init(recordsToSave: [CKRecord]?, recordIDsToDelete: [CKRecordID]?)…}

Batch Operations

iOS

iCloudAccounts New


Batch Operations

iOS

iCloud

CKModifyRecordsOperation

[ ]

Accounts New


Batch Operations

iOS

iCloudAccounts New


Batch OperationsBatch size limits


Server imposed limits


Server imposed limits• Number of items per request


Server imposed limits• Number of items per request• Size of request


Server imposed limits• Number of items per request• Size of requestCKErrorLimitExceeded

Batch OperationsPartial errors


CKErrorPartialFailure



CKPartialErrorsByItemIDKey

CKRecordID : CKError?

CKRecordID : CKErrorInvalidArguments . . . . . . . CKRecordID : CKError?

Batch OperationsPartial errors with atomic updates


CKPartialErrorsByItemIDKey

CKRecordID : CKErrorBatchRequestFailed

CKRecordID : CKErrorInvalidArguments . . . . . . . CKRecordID : CKErrorBatchRequestFailed

Queries

QueriesIn ClownCentral


let query = CKQuery(recordType: "Photo", predicate: NSPredicate(format: "Party == %@", partyRecordID))



Parties may have a lot of photos



Parties may have a lot of photosOptimize download with CKQueryOperation

CKQueryOperationHow many photos do we need?

Accounts New



let queryOperation = CKQueryOperation… queryOperation.resultsLimit = 20

Accounts New




Also available on:

Accounts New




Also available on:• CKFetchRecordChangesOperation

Accounts New




Also available on:• CKFetchRecordChangesOperation

• CKFetchNotificationChangesOperation

Accounts New


Accounts New


CKQueryOperationWhat kind of photo do we need?

Photo

Accounts New



Photo

“photoAsset” =

Accounts New



Photo

“photoAsset” =

“photoThumbnail” =


Accounts New



let queryOperation = CKQueryOperation…queryOperation.desiredKeys = ["photoThumbnail"]

Accounts New




Also available on:

Accounts New




Also available on:• CKFetchRecordsOperation

Accounts New




Also available on:• CKFetchRecordsOperation

• CKFetchRecordChangesOperation

Accounts New


CKQueryOperationFetching in order

AccountsAccounts New



let byCreation = NSSortDescriptor(key: "creationDate", ascending: false)query.sortDescriptors = [byCreation]





System field sort





System field sort• Configure via iCloud Dashboard



CKQueryOperationWhat about the rest?

Accounts New



PaginationAccounts New



Paginationvar queryCompletionBlock:((CKQueryCursor?, NSError?) -> Void)?

Accounts New



Paginationvar queryCompletionBlock:((CKQueryCursor?, NSError?) -> Void)?

convenience init(cursor: CKQueryCursor)

Accounts New


Maintaining a Local Cache

Little Data, Many Clients


Personal notes for parties


Personal notes for parties• Private database


Personal notes for parties• Private database• Offline use


Personal notes for parties• Private database• Offline use• Small amount of data needed on all devices

Private Database Downloads


let notesZone = CKRecordZone(zoneName: "NotesZone")



Two main ways:



Two main ways:• CKQueryOperation




• Delta downloads using CKFetchRecordChangesOperation




• Delta downloads using CKFetchRecordChangesOperation- Custom zone with CKRecordZoneCapabilityFetchChanges

Local Store

Storing Data LocallyApp objects

Party

PartyName My Party

PartyDate June 11, 2015

PartyNotes <TextBlob>

Local Store

Party

Storing Data Locally

Record ID FDFE37608477

ChangeTag A

PartyName My Party



CKRecord

Storing Records LocallyArchiving system fields

let record = …

let archivedData = NSMutableData() let archiver = NSKeyedArchiver(forWritingWithMutableData: archivedData) archiver.requiresSecureCoding = true record.encodeSystemFieldsWithCoder(archiver) archiver.finishEncoding()

Local Store

Party

Storing Records Locally


ChangeTag A

PartyName My Party



Archiving system fields

Storing Records LocallyUnarchiving system fields

let record = …

let archivedData = NSMutableData()let archiver = NSKeyedArchiver(forWritingWithMutableData: archivedData)archiver.requiresSecureCoding = truerecord.encodeSystemFieldsWithCoder(archiver)archiver.finishEncoding()


let record = …

let archivedData = NSMutableData()let archiver = NSKeyedArchiver(forWritingWithMutableData: archivedData)archiver.requiresSecureCoding = truerecord.encodeSystemFieldsWithCoder(archiver)archiver.finishEncoding()

let unarchiver = NSKeyedUnarchiver(forReadingWithData: archivedData)unarchiver.requiresSecureCoding = truelet unarchivedRecord = CKRecord(coder: unarchiver)


Local Store

Party


Local Store

Party


ChangeTag A


Local Store

Party


ChangeTag A

PartyName


Local Store

Party


ChangeTag A

PartyName WWDC Bash

Local Store

Storing Records Locally

Party


ChangeTag A

PartyName My PartyWWDC Bash

Unarchiving system fields

Efficiently Fetching Changes


CKFetchRecordChangesOperation



Notifications using CKSubscription



Notifications using CKSubscription• Silent notifications

Subscriptions

Subscription RecapWhat is it?

1

Subscription Recap

Persistent queries on the server

What is it?

1

Subscription Recap

Persistent queries on the serverRemote notification per relevant change

What is it?

1

Subscription Recap

Persistent queries on the serverRemote notification per relevant change• Query subscriptions

What is it?

1

Subscription Recap

Persistent queries on the serverRemote notification per relevant change• Query subscriptions• Zone subscriptions

What is it?

1

Subscription RecapSetup

Subscription Recap

• APS capability managed from Developer Portal

Setup

Subscription Recap

• APS capability managed from Developer Portal• aps-environment entitlement

Setup

Subscription Recap

• APS capability managed from Developer Portal• aps-environment entitlement• Registration via UIApplication

Setup

Subscription Recap


registerForRemoteNotifications()

Setup

Subscription Recap


registerForRemoteNotifications()

registerUserNotificationSettings(notificationSettings: UIUserNotificationSettings)

Setup

CloudKit Push Priorities


High priority push if CKNotificationInfo sets:


High priority push if CKNotificationInfo sets:• alertBody



• shouldBadge



• shouldBadge

• soundName



• shouldBadge

• soundName

Medium priority or “silent” otherwise

Silent Push NotificationsHow do I get one?


1. Remote notification background mode


2.func application(application: UIApplication,didReceiveRemoteNotification: [NSObject : AnyObject], fetchCompletionHandler: (UIBackgroundFetchResult) -> Void) {… }


3. CKNotificationInfo


3. CKNotificationInfo• shouldSendContentAvailable = true


3. CKNotificationInfo• shouldSendContentAvailable = true

• No alertBody, shouldBadge or soundName

Silent Push Notifications


System opportune time


System opportune timePush delivery is best-effort


System opportune timePush delivery is best-effort• May get dropped or coalesced


Sync notification collection


Sync notification collection• CKFetchNotificationChangesOperation



Background task API:



Background task API:class UIApplication : UIResponder { func beginBackgroundTaskWithName(taskName: String?, expirationHandler: (() -> Void)?) -> UIBackgroundTaskIdentifier…}

Interactive Notifications


Join Ignore

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class CKNotificationInfo : NSObject, …{ var category: String?…}


Join Ignore

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class CKNotificationInfo : NSObject, …{ var category: String?…}

• See UIMutableUserNotificationCategory

CloudKit Performance Tips

Managing Dependent Tasks


CloudKit API is asynchronous


CloudKit API is asynchronousTask dependencies are common


CloudKit API is asynchronousTask dependencies are commonGoals:


CloudKit API is asynchronousTask dependencies are commonGoals:• Error handling


CloudKit API is asynchronousTask dependencies are commonGoals:• Error handling• UI performance


CloudKit API is asynchronousTask dependencies are commonGoals:• Error handling• UI performance• Maintainability

Managing Dependent TasksNesting convenience API calls

Managing Dependent TasksNesting convenience API calls

database.fetchRecordWithID(recordID, { record, error in … database.fetchRecordWithID(otherRecordID, { otherRecord, otherError in … database.saveRecord(otherRecord, { savedRecord, anotherError in … }) }) }

Managing Dependent TasksMaking operations synchronous

Managing Dependent TasksMaking operations synchronous

let sema = dispatch_semaphore_create(0) database.fetchRecordWithID(recordID, { record, error in … dispatch_semaphore_signal(sema) } dispatch_semaphore_wait(sema, DISPATCH_TIME_FOREVER)

database.fetchRecordWithID(someOtherRecordID, { otherRecord, otherError in … })

Managing Dependent TasksNSOperation dependencies


class NSOperation : NSObject {

func addDependency(op: NSOperation) func removeDependency(op: NSOperation) var dependencies: [NSOperation] { get } … }


let firstFetch = CKFetchRecordsOperation(…) let secondFetch = CKFetchRecordsOperation(…) … secondFetch.addDependency(firstFetch)

let queue = NSOperationQueue() queue.addOperations([firstFetch, secondFetch], waitUntilFinished: false)

NSOperation Quality of Service


class NSOperation : NSObject { @available(iOS 8.0, *) var qualityOfService: NSQualityOfService…}


class NSOperation : NSObject { @available(iOS 8.0, *) var qualityOfService: NSQualityOfService…}

enum NSQualityOfService : Int { case UserInteractive case UserInitiated case Utility case Background case Default }

Discretionary Networking


Non-user-initiated tasks


Non-user-initiated tasks• Example: pre-fetching content



System waits for an opportune time:



System waits for an opportune time:• Wi-Fi vs. cellular



System waits for an opportune time:• Wi-Fi vs. cellular• Power conditions



System waits for an opportune time:• Wi-Fi vs. cellular• Power conditions

class CKOperation : NSOperation { var usesBackgroundSession: Bool …}

CKOperation Quality of Service


usesBackgroundSession is deprecated


usesBackgroundSession is deprecatedUse qualityOfService



Non-discretionary QoS:



Non-discretionary QoS:.UserInteractive and .UserInitiated



Non-discretionary QoS:.UserInteractive and .UserInitiatedDiscretionary QoS:



Non-discretionary QoS:.UserInteractive and .UserInitiatedDiscretionary QoS:.Utility



Non-discretionary QoS:.UserInteractive and .UserInitiatedDiscretionary QoS:.Utility

.Background (default)

Advanced NSOperationsWhere can I learn more?

Advanced NSOperations Presidio Friday 9:00AM

Summary

Summary

Error handling is vital

Summary

Error handling is vitalBatch requests

Summary

Error handling is vitalBatch requestsSchema trade-offs

Summary

Error handling is vitalBatch requestsSchema trade-offsConfigure CKOperations for performance

More Information

DocumentationCloudKit Resourcesdeveloper.apple.com/cloudkit

Technical SupportApple Developer Forumsdevforums.apple.com

Developer Technical Supportdeveloper.apple.com/support/technical

General [email protected]

http://devforums.apple.com

http://developer.apple.com/support/technica

mailto:[email protected]

Related Sessions

What’s New in CloudKit Mission Tuesday 3:30PM

CloudKit JS and Web Services Pacific Heights Wednesday 3:30PM

Related Lab

CloudKit Lab Frameworks Lab D Friday 9:00AM

cloudkit tips and tricks - apple developer · cloudkit tips and tricks system frameworks session...

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