Cannot Create New Directory in MacOS app

Question

I am working on a mac app. I have been struggling to create a directory in "Desktop" on Mac OS. I am working on High Sierra. It was working fine, but suddenly the app is unable to create a directory in Desktop. I get the following permission error. I am using Xcode 9.3 and swift 4.1.

Error Domain=NSCocoaErrorDomain Code=513 "You don’t have permission to save the file “TestDir” in the folder “Desktop”." UserInfo={NSFilePath=/Users/sj/Library/Containers/com.user.TestSync/Data/Desktop/TestDir, NSUnderlyingError=0x60400044cc60 {Error Domain=NSPOSIXErrorDomain Code=1 "Operation not permitted"

Here is my code:

class DBManager: NSObject {
    static func getDirectoryPath() -> URL {
        let homeDirectory = URL(fileURLWithPath: NSHomeDirectory())
        let desktopPath = homeDirectory.appendingPathComponent("Desktop")
        let databaseFolder = desktopPath.appendingPathComponent("TestDir")

        return databaseFolder
    }

    static func createFolderIfNotExist() {
        let databaseFolder = DBManager.getDirectoryPath()

        if !FileManager().fileExists(atPath: databaseFolder.path) {
            do {
                try FileManager.default.createDirectory(atPath: databaseFolder.path, withIntermediateDirectories: true, attributes: nil)
            } catch {
            print(error)
            }
        }
    }
}

The code works fine if I am to create a directory inside "Documents". But for some reason, I am not able to create inside Desktop even if I have provided read/write access for Desktop to everyone. I have also included the screenshot of the directory where I have to create one.

I tried to create a directory inside "Downloads" but ended with same permission issue. But, again I was successful to create directory inside "Library". So, it seems that the OS is not giving permission to create inside alias directory since both Desktop and Downloads are alias.

Any help is highly appreciated.

Answer 1

That is because your macOS Application is running in the "App Sandbox", check your "Capabilities" tab in the target settings.

~/Library/Containers/%BundleID%/Data/Desktop is a soft link to the user's desktop, and you have no write permissions (depending on your entitlements file not even read permissions).

Depending on your use case you can

• disable the sandbox mode
• let the user pick a folder by opening an "Open" dialog (then you can write to this)
• enable read/write in some other protected user folder (like Downloads, etc.) or
• create the TestDir directly in your home directory without using any soft linked folder