Swift 3: Set Finder label color

Question

I\'m trying to set the colored labels shown by the finder. The only function I know is setResourceValue. But this needs localized names!

I could image my mother lang

Answer 1

History

First there was my previous answer, which works for setting one color label to a file: https://stackoverflow.com/a/39751001/2227743.

Then @mz2 posted this excellent answer which successfully sets several color labels to a file and explains the process: https://stackoverflow.com/a/40314367/2227743.

And now this little add-on, a simple follow-up to @mz2's answer.

Solution

I've simply implemented @mz2's suggestion: I've expanded his enum example with methods for fetching the Finder's preferences and extract the correct localized label color names before setting the attributes to the file.

enum LabelColors: Int {
    case none
    case gray
    case green
    case purple
    case blue
    case yellow
    case red
    case orange

    func label(using list: [String] = []) -> String? {
        if list.isEmpty || list.count < 7 {
            switch self {
            case .none: return nil
            case .gray: return "Gray\n1"
            case .green: return "Green\n2"
            case .purple: return "Purple\n3"
            case .blue: return "Blue\n4"
            case .yellow: return "Yellow\n5"
            case .red: return "Red\n6"
            case .orange: return "Orange\n7"
            }
        } else {
            switch self {
            case .none: return nil
            case .gray: return list[0]
            case .green: return list[1]
            case .purple: return list[2]
            case .blue: return list[3]
            case .yellow: return list[4]
            case .red: return list[5]
            case .orange: return list[6]
            }
        }
    }

    static func set(colors: [LabelColors],
                    to url: URL,
                    using list: [String] = []) throws
    {
        // 'setExtendedAttributeData' is part of https://github.com/billgarrison/SOExtendedAttributes
        try (url as NSURL).setExtendedAttributeData(propertyListData(labels: colors, using: list),
                                                    name: "com.apple.metadata:_kMDItemUserTags")
    }

    static func propertyListData(labels: [LabelColors],
                                 using list: [String] = []) throws -> Data
    {
        let labelStrings = labels.flatMap { $0.label(using: list) }
        return try PropertyListSerialization.data(fromPropertyList: labelStrings,
                                                  format: .binary,
                                                  options: 0)
    }

    static func localizedLabelNames() -> [String] {
        // this doesn't work if the app is Sandboxed:
        // the users would have to point to the file themselves with NSOpenPanel
        let url = URL(fileURLWithPath: "\(NSHomeDirectory())/Library/SyncedPreferences/com.apple.finder.plist")

        let keyPath = "values.FinderTagDict.value.FinderTags"
        if let d = try? Data(contentsOf: url) {
            if let plist = try? PropertyListSerialization.propertyList(from: d,
                                                                       options: [],
                                                                       format: nil),
                let pdict = plist as? NSDictionary,
                let ftags = pdict.value(forKeyPath: keyPath) as? [[AnyHashable: Any]]
            {
                var list = [(Int, String)]()
                // with '.count == 2' we ignore non-system labels
                for item in ftags where item.values.count == 2 {
                    if let name = item["n"] as? String,
                        let number = item["l"] as? Int {
                        list.append((number, name))
                    }
                }
                return list.sorted { $0.0 < $1.0 }.map { "\($0.1)\n\($0.0)" }
            }
        }
        return []
    }
}

Usage:

do {
    // default English label names
    try LabelColors.set(colors: [.yellow, .red],
                        to: fileURL)

    // localized label names
    let list = LabelColors.localizedLabelNames()
    try LabelColors.set(colors: [.green, .blue],
                        to: fileURL,
                        using: list)
} catch {
    print("Error when setting label color(s): \(error)")
}