Swift - Generates a suitable UserAgent string on iOS / macOS / tvOS

userAgent.swift

    static let userAgent: String = {
        
        let info = Bundle.main.infoDictionary
        let executable = (info?[kCFBundleExecutableKey as String] as? String) ??
            (ProcessInfo.processInfo.arguments.first?.split(separator: "/").last.map(String.init)) ??
            "Unknown"
        let bundle = info?[kCFBundleIdentifierKey as String] as? String ?? "Unknown"
        let appVersion = info?["CFBundleShortVersionString"] as? String ?? "Unknown"
        let appBuild = info?[kCFBundleVersionKey as String] as? String ?? "Unknown"
        
        let osNameVersion: String = {
            let version = ProcessInfo.processInfo.operatingSystemVersion
            let versionString = "\(version.majorVersion).\(version.minorVersion).\(version.patchVersion)"
            let osName: String = {
                #if os(iOS)
                #if targetEnvironment(macCatalyst)
                return "macOS(Catalyst)"
                #else
                return "iOS"
                #endif
                #elseif os(watchOS)
                return "watchOS"
                #elseif os(tvOS)
                return "tvOS"
                #elseif os(macOS)
                return "macOS"
                #elseif os(Linux)
                return "Linux"
                #elseif os(Windows)
                return "Windows"
                #else
                return "Unknown"
                #endif
            }()
            
            return "\(osName) \(versionString)"
        }()
        
        return "\(executable)/\(appVersion) (\(bundle); build:\(appBuild); \(osNameVersion))"
        
    }()