axiom-cloudkit-ref

CloudKit 参考

用途：数据库式 iCloud 存储与同步的全面 CloudKit 参考 可用性：iOS 10.0+（基础功能）、iOS 17.0+（CKSyncEngine）、iOS 17.0+（SwiftData 集成） 上下文：通过 CKSyncEngine（WWDC 2023）或 SwiftData 集成实现现代 CloudKit 同步

何时使用此技能

在以下情况使用此技能：

• 实现结构化数据与 iCloud 同步
• 在 SwiftData+CloudKit、CKSyncEngine 或原始 CloudKit API 之间进行选择
• 设置公共、私有或共享数据库
• 实现冲突解决
• 调试 CloudKit 同步问题
• 监控 CloudKit 性能

不适用于：简单文件同步（请改用 axiom-icloud-drive-ref）

概览

CloudKit 用于结构化数据同步（带有关联关系的记录），而非简单文件同步。

三种现代方案：

1. SwiftData + CloudKit（最简单，iOS 17+）
2. CKSyncEngine（自定义持久化，iOS 17+，WWDC 2023）
3. 原始 CloudKit API（控制力最强，但更复杂）

---

方案 1：SwiftData + CloudKit（推荐）

适用场景：使用 SwiftData 模型的 iOS 17+ 应用

限制：

• 仅支持私有数据库（不支持公共/共享数据库）
• 自动同步（控制力较弱）
• CloudKit 同步不支持 @Attribute(.unique) — 使用 CloudKit 时请移除
• 受 SwiftData 限制

// ✅ CORRECT: SwiftData with CloudKit sync
import SwiftData

@Model
class Task {
    var title: String
    var isCompleted: Bool
    var dueDate: Date

    init(title: String, isCompleted: Bool = false, dueDate: Date) {
        self.title = title
        self.isCompleted = isCompleted
        self.dueDate = dueDate
    }
}

// Configure CloudKit container
let container = try ModelContainer(
    for: Task.self,
    configurations: ModelConfiguration(
        cloudKitDatabase: .private("iCloud.com.example.app")
    )
)

// That's it! Sync happens automatically

所需授权：

• iCloud 功能
• CloudKit 容器

SwiftData 详情请使用 axiom-swiftdata 技能

---

方案 2：CKSyncEngine（现代方案，WWDC 2023）

适用场景：使用自定义持久化（SQLite、GRDB、JSON）并与云端同步

相比原始 CloudKit 的优势：

• 自动管理获取/上传周期
• 处理冲突
• 管理账户变更
• 比手动执行 CKDatabase 操作更受推荐

// ✅ CORRECT: CKSyncEngine setup
import CloudKit

class SyncManager {
    let syncEngine: CKSyncEngine

    init() throws {
        let config = CKSyncEngine.Configuration(
            database: CKContainer.default().privateCloudDatabase,
            stateSerialization: loadSyncState(),
            delegate: self
        )

        syncEngine = try CKSyncEngine(config)
    }

    // Implement delegate methods
}

extension SyncManager: CKSyncEngineDelegate {
    // Handle events
    func handleEvent(_ event: CKSyncEngine.Event, syncEngine: CKSyncEngine) async {
        switch event {
        case .stateUpdate(let stateUpdate):
            saveSyncState(stateUpdate.stateSerialization)

        case .accountChange(let change):
            handleAccountChange(change)

        case .fetchedDatabaseChanges(let changes):
            applyDatabaseChanges(changes)

        case .fetchedRecordZoneChanges(let changes):
            applyRecordChanges(changes)

        case .sentRecordZoneChanges(let changes):
            handleSentChanges(changes)

        case .willFetchChanges, .didFetchChanges,
             .willSendChanges, .didSendChanges:
            // Optional lifecycle events
            break

        @unknown default:
            break
        }
    }

    // Next batch of changes to send
    func nextRecordZoneChangeBatch(
        _ context: CKSyncEngine.SendChangesContext,
        syncEngine: CKSyncEngine
    ) async -> CKSyncEngine.RecordZoneChangeBatch? {
        // Return pending local changes
        let pendingChanges = getPendingLocalChanges()
        return CKSyncEngine.RecordZoneChangeBatch(
            pendingSaves: pendingChanges,
            recordIDsToDelete: []
        )
    }
}

关键概念：

• 状态序列化：在应用启动之间持久化同步状态
• 事件：委托对象接收变更事件
• 批次：你提供待处理的变更，由引擎上传
• 自动冲突解决：引擎处理基本冲突

---

方案 3：原始 CloudKit API（旧版）

适用场景：仅当 CKSyncEngine 不适用时（少见）

核心类型：

• CKContainer — 入口点
• CKDatabase — 公共/私有/共享范围
• CKRecord — 单条数据记录
• CKRecordZone — 逻辑分组
• CKAsset — 二进制文件存储

基本操作

// ✅ Container and database
let container = CKContainer.default()
let privateDatabase = container.privateCloudDatabase
let publicDatabase = container.publicCloudDatabase

// ✅ Create record
let record = CKRecord(recordType: "Task")
record["title"] = "Buy groceries"
record["isCompleted"] = false
record["dueDate"] = Date()

// ✅ Save record
try await privateDatabase.save(record)

// ✅ Fetch record
let recordID = CKRecord.ID(recordName: "task-123")
let fetchedRecord = try await privateDatabase.record(for: recordID)

// ✅ Query records
let predicate = NSPredicate(format: "isCompleted == NO")
let query = CKQuery(recordType: "Task", predicate: predicate)
let (matchResults, _) = try await privateDatabase.records(matching: query)

for result in matchResults {
    if case .success(let record) = result.1 {
        print("Task: \(record["title"] as? String ?? "")")
    }
}

// ✅ Delete record
try await privateDatabase.deleteRecord(withID: recordID)

更新记录

// ✅ Fetch-then-modify-then-save (prevents serverRecordChanged errors)
let record = try await privateDatabase.record(for: recordID)
record["title"] = "Updated title"
record["isCompleted"] = true
try await privateDatabase.save(record)

// ✅ Batch modify (save + delete in one operation)
let operation = CKModifyRecordsOperation(
    recordsToSave: [updatedRecord1, updatedRecord2],
    recordIDsToDelete: [deletedID]
)
operation.perRecordSaveBlock = { recordID, result in
    switch result {
    case .success: print("Saved: \(recordID)")
    case .failure(let error): print("Failed: \(recordID) — \(error)")
    }
}
try await privateDatabase.add(operation)

冲突解决

// ✅ Handle conflicts with savePolicy
let operation = CKModifyRecordsOperation(
    recordsToSave: [record],
    recordIDsToDelete: nil
)

// Save only if server version unchanged
operation.savePolicy = .ifServerRecordUnchanged

// OR: Always overwrite server
operation.savePolicy = .changedKeys  // Only changed fields

operation.modifyRecordsResultBlock = { result in
    switch result {
    case .success:
        print("Saved")
    case .failure(let error as CKError):
        if error.code == .serverRecordChanged {
            // Conflict - merge manually
            let serverRecord = error.serverRecord
            let clientRecord = error.clientRecord
            let merged = mergeRecords(server: serverRecord, client: clientRecord)
            // Retry with merged record
        }
    }
}

privateDatabase.add(operation)

---

数据库范围

范围	可访问性	SwiftData 支持	使用场景
私有	仅用户本人	✅ 支持	用户个人数据
公共	所有用户	❌ 不支持	共享/公共内容
共享	受邀用户	❌ 不支持	协作

私有数据库

// ✅ Private database (most common)
let privateDB = CKContainer.default().privateCloudDatabase

// User must be signed into iCloud
// Data syncs across user's devices
// Not visible to other users

公共数据库

// ✅ Public database (for shared content)
let publicDB = CKContainer.default().publicCloudDatabase

// Accessible to all app users
// Even unauthenticated users can read
// Writes require authentication
// Use for: Leaderboards, public content, discovery

共享数据库

// ✅ Shared database (collaboration)
let sharedDB = CKContainer.default().sharedCloudDatabase

// For CKShare-based collaboration
// Users invited to specific record zones
// Use for: Shared documents, team data

---

CloudKit 资源（文件）

// ✅ Store files as CKAsset
let imageURL = saveImageToTempFile(image)  // Must be file URL
let asset = CKAsset(fileURL: imageURL)

let record = CKRecord(recordType: "Photo")
record["image"] = asset
record["caption"] = "Sunset"

try await privateDatabase.save(record)

// ✅ Retrieve asset
let fetchedRecord = try await privateDatabase.record(for: recordID)
if let asset = fetchedRecord["image"] as? CKAsset,
   let fileURL = asset.fileURL {
    let imageData = try Data(contentsOf: fileURL)
    let image = UIImage(data: imageData)
}

重要：CKAsset 需要文件 URL，而非 Data。请先将数据写入临时文件。

---

CloudKit 控制台（监控 — WWDC 2024）

开发者通知

为以下情况设置提醒：

• 架构变更
• 超出配额
• 错误率过高
• 自定义阈值

遥测

监控：

• 请求数量
• 错误率
• 延迟（p50、p95、p99）
• 带宽用量

日志

查看：

• 单个请求
• 错误详情
• 性能瓶颈

访问地址：https://icloud.developer.apple.com/dashboard

---

常见模式

模式 1：初始同步

// ✅ Fetch all records on first launch
func performInitialSync() async throws {
    let predicate = NSPredicate(value: true)  // All records
    let query = CKQuery(recordType: "Task", predicate: predicate)

    let (results, _) = try await privateDatabase.records(matching: query)

    for result in results {
        if case .success(let record) = result.1 {
            saveToLocalDatabase(record)
        }
    }
}

模式 2：增量同步

// ✅ Use CKServerChangeToken for incremental fetches
func fetchChanges(since token: CKServerChangeToken?) async throws {
    let zoneID = CKRecordZone.ID(zoneName: "Tasks")

    let config = CKFetchRecordZoneChangesOperation.ZoneConfiguration(
        previousServerChangeToken: token
    )

    let operation = CKFetchRecordZoneChangesOperation(
        recordZoneIDs: [zoneID],
        configurationsByRecordZoneID: [zoneID: config]
    )

    operation.recordWasChangedBlock = { recordID, result in
        if case .success(let record) = result {
            updateLocalDatabase(with: record)
        }
    }

    operation.recordWithIDWasDeletedBlock = { recordID, _ in
        deleteFromLocalDatabase(recordID)
    }

    operation.recordZoneFetchResultBlock = { zoneID, result in
        if case .success(let (token, _, _)) = result {
            saveChangeToken(token)  // For next fetch
        }
    }

    try await privateDatabase.add(operation)
}

---

授权

Xcode 中所需的授权：

<key>com.apple.developer.icloud-services</key>
<array>
    <string>CloudKit</string>
</array>


<key>com.apple.developer.icloud-container-identifiers</key>
<array>
    <string>iCloud.com.example.app</string>
</array>

设置步骤：

1. Xcode → 目标 → 签名与功能
2. “+ Capability” → iCloud
3. 勾选 “CloudKit”
4. 选择或创建容器

---

订阅（推送通知）

数据库订阅

// ✅ Get notified of ANY change in private database
let subscription = CKDatabaseSubscription(subscriptionID: "all-changes")

let notificationInfo = CKSubscription.NotificationInfo()
notificationInfo.shouldSendContentAvailable = true  // Silent push
subscription.notificationInfo = notificationInfo

try await privateDatabase.save(subscription)

查询订阅

// ✅ Get notified when records matching a query change
let predicate = NSPredicate(format: "priority > 3")
let subscription = CKQuerySubscription(
    recordType: "Task",
    predicate: predicate,
    subscriptionID: "high-priority-tasks",
    options: [.firesOnRecordCreation, .firesOnRecordUpdate, .firesOnRecordDeletion]
)

let notificationInfo = CKSubscription.NotificationInfo()
notificationInfo.alertBody = "High priority task changed"
notificationInfo.shouldBadge = true
subscription.notificationInfo = notificationInfo

try await privateDatabase.save(subscription)

区域订阅

// ✅ Get notified of any change in a specific zone
let zoneID = CKRecordZone.ID(zoneName: "Tasks")
let subscription = CKRecordZoneSubscription(
    zoneID: zoneID,
    subscriptionID: "tasks-zone"
)

let notificationInfo = CKSubscription.NotificationInfo()
notificationInfo.shouldSendContentAvailable = true
subscription.notificationInfo = notificationInfo

try await privateDatabase.save(subscription)

处理推送通知

// In AppDelegate
func application(_ application: UIApplication,
                 didReceiveRemoteNotification userInfo: [AnyHashable: Any]) async -> UIBackgroundFetchResult {
    let notification = CKNotification(fromRemoteNotificationDictionary: userInfo)

    if notification.subscriptionID == "all-changes" {
        try? await fetchChanges(since: savedChangeToken)
        return .newData
    }
    return .noData
}

---

共享记录

创建共享

// ✅ Share a record with other users
let record = try await privateDatabase.record(for: recordID)

// Record must be in a custom zone (not default zone)
let share = CKShare(rootRecord: record)
share[CKShare.SystemFieldKey.title] = "Shared Task List"
share.publicPermission = .none  // Invite-only

// Save both the record and share together
let operation = CKModifyRecordsOperation(
    recordsToSave: [record, share],
    recordIDsToDelete: nil
)
try await privateDatabase.add(operation)

显示共享界面

import CloudKit
import UIKit

// ✅ UIKit sharing controller
let sharingController = UICloudSharingController(share: share, container: container)
sharingController.delegate = self
present(sharingController, animated: true)

// Delegate methods
extension ViewController: UICloudSharingControllerDelegate {
    func cloudSharingController(_ csc: UICloudSharingController,
                                failedToSaveShareWithError error: Error) {
        print("Share failed: \(error)")
    }

    func itemTitle(for csc: UICloudSharingController) -> String? {
        return "My Shared List"
    }
}

管理参与者

// ✅ Check participants
for participant in share.participants {
    print("\(participant.userIdentity.nameComponents?.givenName ?? "Unknown")")
    print("  Acceptance: \(participant.acceptanceStatus)")
    print("  Permission: \(participant.permission)")
    // .readOnly, .readWrite, .none
}

// ✅ Remove participant
share.removeParticipant(participant)
try await privateDatabase.save(share)

接受共享

// In SceneDelegate or AppDelegate
func userDidAcceptCloudKitShareWith(_ cloudKitShareMetadata: CKShare.Metadata) {
    let operation = CKAcceptSharesOperation(shareMetadatas: [cloudKitShareMetadata])
    operation.acceptSharesResultBlock = { result in
        switch result {
        case .success: print("Share accepted")
        case .failure(let error): print("Accept failed: \(error)")
        }
    }
    CKContainer(identifier: cloudKitShareMetadata.containerIdentifier)
        .add(operation)
}

---

快速参考

任务	现代 API（iOS 17+）	旧版 API
结构化数据同步	SwiftData + CloudKit	CKSyncEngine 或 CKDatabase
自定义持久化同步	CKSyncEngine	CKDatabase
冲突解决	自动（SwiftData/CKSyncEngine）	手动（savePolicy）
账户变更	自动处理	手动检测
监控	CloudKit Console 遥测数据	手动记录

---

相关技能

• axiom-swiftdata — SwiftData 实现详情
• axiom-storage — 选择 CloudKit 还是 iCloud Drive
• axiom-icloud-drive-ref — 基于文件的 iCloud 同步
• axiom-cloud-sync-diag — 调试 CloudKit 同步问题

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最后更新：2025-12-12 技能类型：参考 最低 iOS 版本：10.0（基础功能），17.0（CKSyncEngine、SwiftData 集成） WWDC 场次：2023-10188（CKSyncEngine），2024-10122（CloudKit Console）