Listing all files in a directory on macOS Big Sur

Question

In a different question I asked how to save files on a directory of the user's choosing. The reply was the following code, which works great.

func resolveURL(for key: String) throws -> URL {
    if let data = UserDefaults.standard.data(forKey: key) {
        var isStale = false
        let url = try URL(resolvingBookmarkData: data, options:[.withSecurityScope], bookmarkDataIsStale: &isStale)
        if isStale {
            let newData = try url.bookmarkData(options: [.withSecurityScope])
            UserDefaults.standard.set(newData, forKey: key)
        }
        return url
    } else {
        let panel = NSOpenPanel()
        panel.allowsMultipleSelection = false
        panel.canChooseDirectories = true
        panel.canCreateDirectories = true
        panel.canChooseFiles = false
        if panel.runModal() == .OK,
           let url = panel.url {
            let newData = try url.bookmarkData(options: [.withSecurityScope])
            UserDefaults.standard.set(newData, forKey: key)
            return url
        } else {
            throw ResolveError.cancelled
        }
    }
}

func saveFile(filename: String, contents: String) {
    do {
        let directoryURL = try resolveURL(for: "savedDirectory")
        let documentURL = directoryURL.appendingPathComponent (filename + ".txt")
        print("saving " + documentURL.absoluteString)
        try directoryURL.accessSecurityScopedResource(at: documentURL) { url in
            try contents.write (to: url, atomically: false, encoding: .utf8)
        }
        
    } catch let error as ResolveError {
        print("Resolve error:", error)
    } catch {
        print(error)
    }
}

Now, the next step is to go to the directory the user chose when the app loads, and if any files are there, ready each one and add the contents of those files to the struct I use to hold the data.

Googling a little bit I found that you can read all files in a directory using FileManager.default.contentsOfDirectory so I wrote:

func loadFiles() {
    do {
        let directoryURL = try resolveURL(for: "savedDirectory")
        let contents = try FileManager.default.contentsOfDirectory(at: directoryURL,
                                                        includingPropertiesForKeys: nil,
                                                        options: [.skipsHiddenFiles])
        
        for file in contents {
            print(file.absoluteString)
        }
        
    } catch let error as ResolveError {
        print("Resolve error:", error)
        return
    } catch {
        print(error)
        return
    }
}

But, I get the following error:

Error Domain=NSCocoaErrorDomain Code=257 "The file “myFiles” couldn’t be opened because you don’t have permission to view it." UserInfo={NSURL=file:///Users/aleph/myFiles, NSFilePath=/Users/aleph/myFiles, NSUnderlyingError=0x600000704ba0 {Error Domain=NSPOSIXErrorDomain Code=1 "Operation not permitted"}}

which looking at my code I would guess it's happening because I'm not using directoryURL.accessSecurityScopedResource. I tried to add that, or find any other way, but I'm running into a block and I don't know how to get to the directory saved in savedDirectory, and go through every file, reading its contents.

Thank you for any help

Answer 1

If I use:

directoryURL.startAccessingSecurityScopedResource()
// load the files
directoryURL.stopAccessingSecurityScopedResource()

Then it works.