如何保存安全范围的 URL 供以后使用 macOS

问题描述

我制作了一个Finder extension ，可以为任何文件在 Finder 的上下文菜单中添加一个菜单。 当用户选择这个自定义菜单时，我想访问这个文件，显然他们选择的这个文件可以在文件系统中的任何地方和允许的沙箱区域之外。

func accessFile(url: URL, userID: String, completion: @escaping ([String:Any]?, Error?) -> Void){
    var bookmarks = NSKeyedUnarchiver.unarchiveObject(withFile: bookmarksPath) as? [URL: Data]

    print("Testing if we have access to file")
    // 1. Test if I have access to a file
    let directoryURL = url.deletingLastPathComponent()
    let data = bookmarks?[directoryURL]
    if data == nil{
        print("have not asked for access yet or directory is not saved")
        // 2. If I do not, open a open dialog, and get permission
        let openPanel = NSOpenPanel()
        openPanel.allowsMultipleSelection = false
        openPanel.canChooseDirectories = true
        openPanel.canCreateDirectories = false
        openPanel.canChooseFiles = false
        openPanel.prompt = "Grant Access"
        openPanel.directoryURL = directoryURL

        openPanel.begin { result in
            guard result == .OK, let url = openPanel.url else {return}
        
        
            // 3. obtain bookmark data of folder URL and store it to keyed archive
            do{
                let data = try url.bookmarkData(options: .withSecurityScope, includingResourceValuesForKeys: nil, relativeTo: nil)
            }catch{
                print(error)
            }
            bookmarks?[url] = data
            NSKeyedArchiver.archiveRootObject(bookmarks, toFile: bookmarksPath)
        
            // 4. start using the fileURL via:
            url.startAccessingSecurityScopedResource()
            // < do whatever to file >
            url.stopAccessingSecurityScopedResource()
        }
    }else{
        // We have accessed this directory before, get data from bookmarks
        print("we have access already")
        let directoryURL = url.deletingLastPathComponent()
        guard let data = bookmarks?[directoryURL]! else { return }
        var isStale = false
        let newURL = try? URL(resolvingBookmarkData: data, options: .withSecurityScope, relativeTo: nil, bookmarkDataIsStale: &isStale)
    
        // 3. Now again I start using file URL and upload:
        newURL?.startAccessingSecurityScopedResource()
        // < do whatever to file >
        newURL?.stopAccessingSecurityScopedResource()
    
        }
}

目前它总是请求许可，所以书签没有被保存

让我们通过删除书签和NSOPenPanel代码使一些问题可见：

var bookmarks = NSKeyedUnarchiver.unarchiveObject(withFile: bookmarksPath) as? [URL: Data]
// bookmarks is an optional and can be nil (when the file doesn't exist)

let data = bookmarks?[directoryURL]
if data == nil {
    // NSOpenPanel
    
    do {
        let data = try openPanelUrl.bookmarkData(options: .withSecurityScope, includingResourceValuesForKeys: nil, relativeTo: nil)
        // this data is a local data, the other data didn't change
    } catch {
        print(error)
    }
    
    // bookmarks and data are still nil
    bookmarks?[openPanelUrl] = data
    NSKeyedArchiver.archiveRootObject(bookmarks, toFile: bookmarksPath)
    
    // use url
} else {

    // get the bookmark data again
    guard let data = bookmarks?[directoryURL]! else { return }
    
    // get url from data and use it
}

我会做类似的事情：

var bookmarks: [URL: Data]
if let savedBookmarks = NSKeyedUnarchiver.unarchiveObject(withFile: bookmarksPath) as? [URL: Data] {
    bookmarks = savedBookmarks
}
else {
    bookmarks = [:]
}
// bookmarks is a dictionary and can be saved

if let data = bookmarks[directoryURL] {
    // get url from data and use it
}
else {
    // NSOpenPanel
    
    do {
        if let newData = try openPanelUrl.bookmarkData(options: .withSecurityScope, includingResourceValuesForKeys: nil, relativeTo: nil) {
            // bookmarks and newData are not nil
            bookmarks[openPanelUrl] = newData
            NSKeyedArchiver.archiveRootObject(bookmarks, toFile: bookmarksPath)
            
            // use url
        }
    } catch {
        print(error)
    }
}