我正在开发一个适用于 OS X 10.9 的应用程序，带有 swift、沙盒。
应用需要访问 SQLite 数据库文件。我让用户使用 NSOpenPanel 选择/打开一个文件。然后我用 NSUserDefaults 保存文件路径供以后使用。
我希望每次重新启动应用程序时自动打开此文件。我从 NSUserDefault 获取存储的路径，但是当我使用此路径打开文件时出现错误，说我无权访问该文件。
（它在没有沙盒的情况下工作）
看来书签可以解决我的问题。
是否有一个很好的教程如何在 osx 应用程序中快速使用书签？ 还有什么建议吗？
【问题讨论】：
标签： swift macos nsurl nsfilemanager appstore-sandbox
这是我在http://swiftrien.blogspot.com/2015/07/persisting-file-access-rights-between.html 的帮助下刚刚在 Swift 3 中工作的答案
import Foundation
import Cocoa
var bookmarks = [URL: Data]()
func bookmarkPath() -> String
{
var url = app.applicationDocumentsDirectory
url = url.appendingPathComponent("Bookmarks.dict")
return url.path
}
func loadBookmarks()
{
let path = bookmarkPath()
bookmarks = NSKeyedUnarchiver.unarchiveObject(withFile: path) as! [URL: Data]
for bookmark in bookmarks
{
restoreBookmark(bookmark)
}
}
func saveBookmarks()
{
let path = bookmarkPath()
NSKeyedArchiver.archiveRootObject(bookmarks, toFile: path)
}
func storeBookmark(url: URL)
{
do
{
let data = try url.bookmarkData(options: NSURL.BookmarkCreationOptions.withSecurityScope, includingResourceValuesForKeys: nil, relativeTo: nil)
bookmarks[url] = data
}
catch
{
Swift.print ("Error storing bookmarks")
}
}
func restoreBookmark(_ bookmark: (key: URL, value: Data))
{
let restoredUrl: URL?
var isStale = false
Swift.print ("Restoring \(bookmark.key)")
do
{
restoredUrl = try URL.init(resolvingBookmarkData: bookmark.value, options: NSURL.BookmarkResolutionOptions.withSecurityScope, relativeTo: nil, bookmarkDataIsStale: &isStale)
}
catch
{
Swift.print ("Error restoring bookmarks")
restoredUrl = nil
}
if let url = restoredUrl
{
if isStale
{
Swift.print ("URL is stale")
}
else
{
if !url.startAccessingSecurityScopedResource()
{
Swift.print ("Couldn't access: \(url.path)")
}
}
}
}
func allowFolder() -> URL?
{
let openPanel = NSOpenPanel()
openPanel.allowsMultipleSelection = false
openPanel.canChooseDirectories = true
openPanel.canCreateDirectories = true
openPanel.canChooseFiles = false
openPanel.begin
{ (result) -> Void in
if result == NSFileHandlingPanelOKButton
{
let url = openPanel.url
storeBookmark(url: url!)
}
}
return openPanel.url
}
Swift 4（更新）：
import Foundation
import Cocoa
var bookmarks = [URL: Data]()
func fileExists(_ url: URL) -> Bool
{
var isDir = ObjCBool(false)
let exists = FileManager.default.fileExists(atPath: url.path, isDirectory: &isDir)
return exists
}
func bookmarkURL() -> URL
{
let urls = FileManager.default.urls(for: .applicationSupportDirectory, in: .userDomainMask)
let appSupportURL = urls[urls.count - 1]
let url = appSupportURL.appendingPathComponent("Bookmarks.dict")
return url
}
func loadBookmarks()
{
let url = bookmarkURL()
if fileExists(url)
{
do
{
let fileData = try Data(contentsOf: url)
if let fileBookmarks = try NSKeyedUnarchiver.unarchiveTopLevelObjectWithData(fileData) as! [URL: Data]?
{
bookmarks = fileBookmarks
for bookmark in bookmarks
{
restoreBookmark(bookmark)
}
}
}
catch
{
print ("Couldn't load bookmarks")
}
}
}
func saveBookmarks()
{
let url = bookmarkURL()
do
{
let data = try NSKeyedArchiver.archivedData(withRootObject: bookmarks, requiringSecureCoding: false)
try data.write(to: url)
}
catch
{
print("Couldn't save bookmarks")
}
}
func storeBookmark(url: URL)
{
do
{
let data = try url.bookmarkData(options: NSURL.BookmarkCreationOptions.withSecurityScope, includingResourceValuesForKeys: nil, relativeTo: nil)
bookmarks[url] = data
}
catch
{
Swift.print ("Error storing bookmarks")
}
}
func restoreBookmark(_ bookmark: (key: URL, value: Data))
{
let restoredUrl: URL?
var isStale = false
Swift.print ("Restoring \(bookmark.key)")
do
{
restoredUrl = try URL.init(resolvingBookmarkData: bookmark.value, options: NSURL.BookmarkResolutionOptions.withSecurityScope, relativeTo: nil, bookmarkDataIsStale: &isStale)
}
catch
{
Swift.print ("Error restoring bookmarks")
restoredUrl = nil
}
if let url = restoredUrl
{
if isStale
{
Swift.print ("URL is stale")
}
else
{
if !url.startAccessingSecurityScopedResource()
{
Swift.print ("Couldn't access: \(url.path)")
}
}
}
}
func allowFolder() -> URL?
{
let openPanel = NSOpenPanel()
openPanel.allowsMultipleSelection = false
openPanel.canChooseDirectories = true
openPanel.canCreateDirectories = true
openPanel.canChooseFiles = false
openPanel.begin
{ (result) -> Void in
if result == NSFileHandlingPanelOKButton
{
let url = openPanel.url
storeBookmark(url: url!)
}
}
return openPanel.url
}
要使用此代码，您必须首先调用 NSOpenPanel，以便用户可以选择授予您访问权限的文件夹。 NSOpenPanel 必须存储为书签并保存到磁盘。
let url = allowFolder()
saveBookmarks()
当您重新启动应用程序时，您必须调用
loadBookmarks()
那么您的应用将拥有与用户选择文件夹时相同的访问级别。希望这对某人有所帮助。
【讨论】：
isStale == true，看来你得打电话给url.startAccessingSecurityScopedResource。否则将无法正常工作。
这里有更简洁的 SWIFT 5.0 解决方案：
import Foundation
import Cocoa
class BookmarkManager {
static let manager = BookmarkManager()
// Save bookmark for URL. Use this inside the NSOpenPanel `begin` closure
func saveBookmark(for url: URL){
guard let bookmarkDic = self.getBookmarkData(url: url),
let bookmarkURL = getBookmarkURL() else{
print("Error getting data or bookmarkURL")
return
}
do
{
let data = try NSKeyedArchiver.archivedData(withRootObject: bookmarkDic, requiringSecureCoding: false)
try data.write(to: bookmarkURL)
print("Did save data to url")
}
catch
{
print("Couldn't save bookmarks")
}
}
// Load bookmarks when your app launch for example
func loadBookmarks()
{
guard let url = self.getBookmarkURL() else {
return
}
if self.fileExists(url)
{
do
{
let fileData = try Data(contentsOf: url)
if let fileBookmarks = try NSKeyedUnarchiver.unarchiveTopLevelObjectWithData(fileData) as! [URL: Data]?
{
for bookmark in fileBookmarks{
self.restoreBookmark(key: bookmark.key, value: bookmark.value)
}
}
}
catch
{
print ("Couldn't load bookmarks")
}
}
}
private func restoreBookmark(key: URL, value: Data){
let restoredUrl: URL?
var isStale = false
Swift.print ("Restoring \(key)")
do
{
restoredUrl = try URL.init(resolvingBookmarkData: value, options: NSURL.BookmarkResolutionOptions.withSecurityScope, relativeTo: nil, bookmarkDataIsStale: &isStale)
}
catch
{
Swift.print ("Error restoring bookmarks")
restoredUrl = nil
}
if let url = restoredUrl
{
if isStale
{
Swift.print ("URL is stale")
}
else
{
if !url.startAccessingSecurityScopedResource()
{
Swift.print ("Couldn't access: \(url.path)")
}
}
}
}
private func getBookmarkData(url: URL) -> [URL: Data]?{
let data = try? url.bookmarkData(options: NSURL.BookmarkCreationOptions.withSecurityScope, includingResourceValuesForKeys: nil, relativeTo: nil)
if let data = data{
return [url: data]
}
return nil
}
private func getBookmarkURL() -> URL? {
let urls = FileManager.default.urls(for: .applicationSupportDirectory, in: .userDomainMask)
if let appSupportURL = urls.last{
let url = appSupportURL.appendingPathComponent("Bookmarks.dict")
return url
}
return nil
}
private func fileExists(_ url: URL) -> Bool
{
var isDir = ObjCBool(false)
let exists = FileManager.default.fileExists(atPath: url.path, isDirectory: &isDir)
return exists
}
}
【讨论】：
安全范围的书签正是要走的路。好的起点是 AppStore 沙箱上的苹果文档（包括示例代码）和 NSFileManager 的类参考。
然后您将不会将路径存储在用户默认值中，而是将书签的二进制数据存储。
【讨论】：