How can I get the file creation date using URL resourceValues method in Swift 3?

Question

Thanks to a variety of helpful posts in this forum, I have some code that works for obtaining the Creation Date of a single user-selected NSURL. However, I cannot get the code to work for either a hard-coded NSURL, nor within a loop through an NSFileManager enumerator.

I am not a professional programmer; I make apps that are tools for office. My ultimate goal is to simply sort an Array of NSURL objects based on Creation Date.

The code I am using is below, which functions just fine as is, but if I try to use the commented line to evaluate a specific PDF file, I get the following error:

I get the exact same error when I try to add this code to a loop of NSURL objects procured via the NSFileManager Enumerator.

I cannot figure out how to use the error instruction to solve the problem. If anyone can assist, that would be tremendous. Thank you.

let chosenURL = NSOpenPanel().selectFile

    //let chosenURL = NSURL.fileURL(withPath: "/Users/craigsmith/Desktop/PDFRotator Introduction.pdf")

    do
    {
        var cr:AnyObject?
        try chosenURL?.getResourceValue(&cr, forKey: URLResourceKey.creationDateKey)

        if (cr != nil)
        {
            if let createDate = cr as? NSDate
            {
                print("Seems to be a date: \(createDate)")

                let theComparison = createDate.compare(NSDate() as Date)

                print("Result of Comparison: \(theComparison)")  // Useless

                let interval = createDate.timeIntervalSinceNow

                print("Interval: \(interval)")

                if interval < (60*60*24*7*(-1))
                {
                    print("More than a week ago")

                }
                else
                {
                    print("Less than a week ago")
                }
            }
            else
            {
                print("Not a Date")
            }
        }
    }
    catch
    {

    }

Answer 1

You can extend URL as follow:

extension URL {
    var creationDate: Date? {
        return (try? resourceValues(forKeys: [.creationDateKey]))?.creationDate
    }
}

usage:

print(yourURL.creationDate)

Answer 2

According to the header doc of URL and URLResourceValues, you may need to write something like this:

(This code is assuming chosenURL is of type URL?.)

do {
    if
        let resValues = try chosenURL?.resourceValues(forKeys: [.creationDateKey]),
        let createDate = resValues.creationDate
    {
        //Use createDate here...
    }
} catch {
    //...
}

(If your chosenURL is of type NSURL?, try this code.)

do {
    if
        let resValues = try (chosenURL as URL?)?.resourceValues(forKeys: [.creationDateKey]),
        let createDate = resValues.creationDate
    {
        //Use createDate here...
        print(createDate)
    }
} catch {
    //...
}

I recommend you to use URL rather than NSURL, as far as you can.

Answer 3

in swift 5 I use the following code:

let attributes = try! FileManager.default.attributesOfItem(atPath: item.path)
let creationDate = attributes[.creationDate] as! Date

sort array with the following code

fileArray = fileArray.sorted(by: {
        $0.creationDate.compare($1.creationDate) == .orderedDescending
    })

more about FileAttributeKey here: https://developer.apple.com/documentation/foundation/fileattributekey