Cocoa icon for file type?

Question

If I have a file, I can get the icon by doing something such as:

NSImage *iconImage = [[NSWorkspace sharedWorkspace] iconForFile: @\"myFile.png\"];

Answer 1

Here is the Swift 5 version of PetrV's answer:

public extension NSWorkspace {

    /// Returns an image containing the icon for files of the same type as the file at the specified path.
    ///
    /// - Parameter filePath: The full path to the file.
    /// - Returns: The icon associated with files of the same type as the file at the given path.
    func icon(forFileTypeAtSamplePath filePath: String) -> NSImage? {
        let fileExtension = URL(fileURLWithPath: filePath).pathExtension
        guard
            let unmanagedFileUti = UTTypeCreatePreferredIdentifierForTag(kUTTagClassFilenameExtension,
                                                                         fileExtension as CFString, nil),
            let fileUti = unmanagedFileUti.takeRetainedValue() as String?
            else {
                assertionFailure("Should've gotten a UTI for \(fileExtension)")
                return nil
        }

        return NSWorkspace.shared.icon(forFileType: fileUti)
    }
}