问题
I am working on an app for OS X 10.9 with swift, sandboxed.
The app needs access to a SQLite database file. I let the user choose/open a file with NSOpenPanel. I then save the file path with NSUserDefaults for later use.
I want this file to be opened automatically every time when the app is started again. I get the stored path from the NSUserDefault, but when I open the file with this path I get an error, saying I have no permission to access the file.
(it is working without sandboxing)
It looks like bookmark's are the solution to my problem.
Is there a good tutorial how to use bookmark's with swift for an osx app? Any other suggestion?
回答1:
Here is my answer that I've just got working in Swift 3 with a little help from http://swiftrien.blogspot.com/2015/07/persisting-file-access-rights-between.html
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 (update):
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
}
To use this code you must first call NSOpenPanel so the user can select which folders to give you access to. The NSOpenPanel must be stored as a bookmark and saved to disk.
let url = allowFolder()
saveBookmarks()
When you restart the application you must call
loadBookmarks()
then your app will have the same level of access as it did when the user selected the folder. Hope this helps someone.
回答2:
security scoped bookmarks is exactly the way to go. good starting point is apple documentation on AppStore sandbox (which includes sample code) and class reference of NSFileManager.
you then will not store the path in user defaults but the binary data of the bookmark.
来源：https://stackoverflow.com/questions/31278869/file-access-in-a-sandboxed-mac-app-with-swift