Check if file is alias Swift

Question

How can I check if a file is an Alias on Mac? Here is my code so far:

public func getFiles(){
    let folderPath = "/Users/timeBro/Desktop/testfolder"
    let fileManager = NSFileManager.defaultManager()
    let enumerator:NSDirectoryEnumerator = fileManager.enumeratorAtPath(folderPath)!
    
    for url in enumerator.allObjects {
        
        let newurl = NSURL(string: url as! String)
        print("\(url as! String)")
        print(url);
        print(newurl?.isFileReferenceURL())
    }
}

How can I check if the file is an alias?

Answer 1

There is an easy solution which completely gets by without any pointer handling:

extension URL {
    func isAlias() -> Bool? {
        let values = try? url.resourceValues(forKeys: [.isSymbolicLinkKey, .isAliasFileKey])
        let alias = values?.isAliasFile
        let symbolic = values?.isSymbolicLink

        guard alias != nil, symbolic != nil else { return nil }
        if alias! && !symbolic! {
            return true
        }
        return false
    }
}

Explanation: resourceValues(forKeys:) returns .isAliasFile and .isSymbolicLink for symbolic links so you have to make sure the former is returned and the latter isn’t when checking for aliases. If the path doesn’t exist the function returns nil.