axiom-icloud-drive-ref

iCloud Drive 参考

用途：使用 ubiquitous 容器进行基于文件的 iCloud 同步的综合参考 可用性：iOS 5.0+（基础功能）、iOS 8.0+（iCloud Drive）、iOS 11.0+（现代 API） 背景：基于文件的云存储，而非数据库（结构化数据请使用 CloudKit）

何时使用此技能

在以下情况下使用此技能：

• 实现基于文稿的 iCloud 同步
• 在设备间同步用户文件
• 构建基于文稿的应用（如 Pages、Numbers）
• 协调多个进程间的文件访问
• 处理 iCloud 文件冲突
• 使用 NSUbiquitousKeyValueStore 同步偏好设置

不适用于：具有关系的结构化数据（请改用 axiom-cloudkit-ref）

---

概述

iCloud Drive 用于基于文件的同步，而非结构化数据。

适用场景：

• 用户创建或编辑文稿
• 文件需要像 Dropbox 一样同步
• 集成文稿选择器

不适用场景：

• 需要可查询的结构化数据（请使用 CloudKit）
• 需要记录间的关系（请使用 CloudKit）
• 少量键值偏好设置（请使用 NSUbiquitousKeyValueStore）

---

ubiquitous 容器

获取 ubiquitous 容器 URL

// ✅ CORRECT: Get iCloud container
func getICloudContainerURL() -> URL? {
    // nil = use first container in entitlements
    return FileManager.default.url(
        forUbiquityContainerIdentifier: nil
    )
}

// ✅ Check if iCloud is available
if let iCloudURL = getICloudContainerURL() {
    print("iCloud available: \(iCloudURL)")
} else {
    print("iCloud not available (not signed in or no entitlement)")
}

容器结构

iCloud Container/
├── Documents/          # User-visible files (Files app)
│   └── MyApp/         # Your app's documents
├── Library/           # Hidden from user
│   ├── Application Support/
│   └── Caches/

保存到 iCloud Drive

// ✅ CORRECT: Save document to iCloud
func saveToICloud(data: Data, filename: String) throws {
    guard let iCloudURL = FileManager.default.url(
        forUbiquityContainerIdentifier: nil
    ) else {
        throw iCloudError.notAvailable
    }

    let documentsURL = iCloudURL.appendingPathComponent("Documents")

    // Create directory if needed
    try FileManager.default.createDirectory(
        at: documentsURL,
        withIntermediateDirectories: true
    )

    let fileURL = documentsURL.appendingPathComponent(filename)

    // Use file coordination for safe access
    let coordinator = NSFileCoordinator()
    var error: NSError?

    coordinator.coordinate(
        writingItemAt: fileURL,
        options: .forReplacing,
        error: &error
    ) { newURL in
        try? data.write(to: newURL)
    }

    if let error = error {
        throw error
    }
}

---

文件协调（安全关键）

访问 iCloud 文件时，始终使用 NSFileCoordinator。这可以防止：

• 与同步发生竞态条件
• 数据损坏
• 更新丢失

读取文件

// ✅ CORRECT: Coordinated read
func readICloudFile(url: URL) throws -> Data {
    let coordinator = NSFileCoordinator()
    var data: Data?
    var coordinationError: NSError?

    coordinator.coordinate(
        readingItemAt: url,
        options: [],
        error: &coordinationError
    ) { newURL in
        data = try? Data(contentsOf: newURL)
    }

    if let error = coordinationError {
        throw error
    }

    guard let data = data else {
        throw fileError.readFailed
    }

    return data
}

写入文件

// ✅ CORRECT: Coordinated write
func writeICloudFile(data: Data, to url: URL) throws {
    let coordinator = NSFileCoordinator()
    var coordinationError: NSError?

    coordinator.coordinate(
        writingItemAt: url,
        options: .forReplacing,
        error: &coordinationError
    ) { newURL in
        try? data.write(to: newURL)
    }

    if let error = coordinationError {
        throw error
    }
}

移动文件

// ✅ CORRECT: Coordinated move
func moveFile(from sourceURL: URL, to destURL: URL) throws {
    let coordinator = NSFileCoordinator()
    var coordinationError: NSError?

    coordinator.coordinate(
        writingItemAt: sourceURL,
        options: .forMoving,
        writingItemAt: destURL,
        options: .forReplacing,
        error: &coordinationError
    ) { newSource, newDest in
        try? FileManager.default.moveItem(at: newSource, to: newDest)
    }

    if let error = coordinationError {
        throw error
    }
}

---

iCloud 的 URL 资源值

检查 iCloud 状态

// ✅ Check if file is in iCloud
func isInICloud(url: URL) -> Bool {
    let values = try? url.resourceValues(forKeys: [.isUbiquitousItemKey])
    return values?.isUbiquitousItem ?? false
}

// ✅ Check download status
func getDownloadStatus(url: URL) -> String {
    let values = try? url.resourceValues(forKeys: [
        .ubiquitousItemDownloadingStatusKey,
        .ubiquitousItemIsDownloadingKey,
        .ubiquitousItemDownloadingErrorKey
    ])

    if let downloading = values?.ubiquitousItemIsDownloading, downloading {
        return "Downloading..."
    }

    if let status = values?.ubiquitousItemDownloadingStatus {
        switch status {
        case .current:
            return "Downloaded"
        case .notDownloaded:
            return "Not downloaded (iCloud only)"
        case .downloaded:
            return "Downloaded"
        @unknown default:
            return "Unknown"
        }
    }

    return "Unknown"
}

// ✅ Check upload status
func isUploading(url: URL) -> Bool {
    let values = try? url.resourceValues(forKeys: [.ubiquitousItemIsUploadingKey])
    return values?.ubiquitousItemIsUploading ?? false
}

// ✅ Check for conflicts
func hasConflicts(url: URL) -> Bool {
    let values = try? url.resourceValues(forKeys: [
        .ubiquitousItemHasUnresolvedConflictsKey
    ])
    return values?.ubiquitousItemHasUnresolvedConflicts ?? false
}

下载文件

// ✅ CORRECT: Request download
func downloadFromICloud(url: URL) throws {
    try FileManager.default.startDownloadingUbiquitousItem(at: url)
}

// ✅ Monitor download progress
let query = NSMetadataQuery()
query.predicate = NSPredicate(format: "%K == %@",
    NSMetadataItemURLKey, url as NSURL)
query.searchScopes = [NSMetadataQueryUbiquitousDataScope]

NotificationCenter.default.addObserver(
    forName: .NSMetadataQueryDidUpdate,
    object: query,
    queue: .main
) { notification in
    // Check progress
    if let item = query.results.first as? NSMetadataItem {
        if let percent = item.value(forAttribute: NSMetadataUbiquitousItemPercentDownloadedKey) as? Double {
            print("Downloaded: \(percent)%")
        }
    }
}

query.start()

---

冲突解决

检测冲突

// ✅ Get conflict versions
func getConflictVersions(for url: URL) -> [NSFileVersion]? {
    return NSFileVersion.unresolvedConflictVersionsOfItem(at: url)
}

解决冲突

// ✅ CORRECT: Resolve conflicts
func resolveConflicts(at url: URL, keepingVersion: ConflictResolution) throws {
    guard let conflicts = NSFileVersion.unresolvedConflictVersionsOfItem(at: url),
          !conflicts.isEmpty else {
        return  // No conflicts
    }

    let current = try NSFileVersion.currentVersionOfItem(at: url)

    switch keepingVersion {
    case .current:
        // Keep current version, discard others
        for conflict in conflicts {
            conflict.isResolved = true
        }

    case .other(let chosenVersion):
        // Replace current with chosen conflict version
        try chosenVersion.replaceItem(at: url, options: [])
        chosenVersion.isResolved = true

        // Mark other conflicts as resolved
        for conflict in conflicts where conflict != chosenVersion {
            conflict.isResolved = true
        }

    case .manual:
        // App merges manually, then marks resolved
        let mergedData = mergeConflicts(current: current, conflicts: conflicts)
        try mergedData.write(to: url)

        for conflict in conflicts {
            conflict.isResolved = true
        }
    }

    // Remove resolved versions
    try NSFileVersion.removeOtherVersionsOfItem(at: url)
}

enum ConflictResolution {
    case current
    case other(NSFileVersion)
    case manual
}

---

NSUbiquitousKeyValueStore（偏好设置同步）

仅用于少量偏好设置（总计 <1 MB，少于 1024 个键）

// ✅ CORRECT: Sync small preferences
let store = NSUbiquitousKeyValueStore.default

// Set values
store.set(true, forKey: "darkModeEnabled")
store.set(2.0, forKey: "textSizeMultiplier")
store.set(["en", "es"], forKey: "selectedLanguages")

// Synchronize
store.synchronize()

// Read values
let darkMode = store.bool(forKey: "darkModeEnabled")
let textSize = store.double(forKey: "textSizeMultiplier")

// Listen for changes from other devices
NotificationCenter.default.addObserver(
    forName: NSUbiquitousKeyValueStore.didChangeExternallyNotification,
    object: store,
    queue: .main
) { notification in
    // Update UI with new values
    updatePreferences()
}

限制：

• 总存储空间：1 MB
• 最大键数：1024
• 最大值大小：1 MB
• 仅用于偏好设置，不用于数据

---

权限配置

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


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


<key>com.apple.developer.ubiquity-kvstore-identifier</key>
<string>$(TeamIdentifierPrefix)com.example.app</string>

---

常见模式

模式 1：集成文稿选择器

// ✅ Present iCloud document picker
import UniformTypeIdentifiers

let picker = UIDocumentPickerViewController(
    forOpeningContentTypes: [.pdf, .plainText]
)
picker.delegate = self
picker.allowsMultipleSelection = false

// Enable iCloud
picker.directoryURL = getICloudContainerURL()

present(picker, animated: true)

模式 2：监视目录更改

// ✅ Monitor iCloud directory
class ICloudMonitor {
    let query = NSMetadataQuery()

    func startMonitoring(directory: URL) {
        query.predicate = NSPredicate(format: "%K BEGINSWITH %@",
            NSMetadataItemPathKey, directory.path)

        query.searchScopes = [NSMetadataQueryUbiquitousDataScope]

        NotificationCenter.default.addObserver(
            forName: .NSMetadataQueryDidUpdate,
            object: query,
            queue: .main
        ) { [weak self] _ in
            self?.processResults()
        }

        query.start()
    }

    func processResults() {
        for item in query.results {
            if let metadataItem = item as? NSMetadataItem,
               let url = metadataItem.value(forAttribute: NSMetadataItemURLKey) as? URL {
                print("File: \(url.lastPathComponent)")
            }
        }
    }
}

---

快速参考

任务	API	说明
获取 iCloud URL	FileManager.default.url(forUbiquityContainerIdentifier:)	不可用时返回 nil
检查是否位于 iCloud 中	.isUbiquitousItemKey 资源值	Bool
下载文件	startDownloadingUbiquitousItem(at:)	异步操作，使用 NSMetadataQuery 监视
检查下载状态	.ubiquitousItemDownloadingStatusKey	current/notDownloaded/downloaded
检查是否存在冲突	.ubiquitousItemHasUnresolvedConflictsKey	Bool
解决冲突	NSFileVersion.unresolvedConflictVersionsOfItem(at:)	手动合并或选择版本
同步偏好设置	NSUbiquitousKeyValueStore.default	总计 <1 MB
文件协调	NSFileCoordinator	处理 iCloud 文件时始终使用

---

相关技能

• axiom-storage — 选择 iCloud Drive 或 CloudKit
• axiom-cloudkit-ref — 用于结构化数据同步
• axiom-cloud-sync-diag — 调试 iCloud 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：5.0（基础功能）、8.0（iCloud Drive）、11.0（现代 API）