Converting URL to String and back again

Question

So I have converted an NSURL to a String. So if I println it looks like file:///Users/... etc.

Later I want this

Answer 1

Swift 5.

To convert a String to a URL:

let stringToURL = URL(string: "your-string")

To convert a URL to a String:

let urlToString = stringToURL?.absoluteString

Answer 2

Swift 3 (forget about NSURL).

let fileName = "20-01-2017 22:47"
let folderString = "file:///var/mobile/someLongPath"

To make a URL out of a string:

let folder: URL? = Foundation.URL(string: folderString)
// Optional<URL>
//  ▿ some : file:///var/mobile/someLongPath

If we want to add the filename. Note, that appendingPathComponent() adds the percent encoding automatically:

let folderWithFilename: URL? = folder?.appendingPathComponent(fileName)
// Optional<URL>
//  ▿ some : file:///var/mobile/someLongPath/20-01-2017%2022:47

When we want to have String but without the root part (pay attention that percent encoding is removed automatically):

let folderWithFilename: String? = folderWithFilename.path
// ▿ Optional<String>
//  - some : "/var/mobile/someLongPath/20-01-2017 22:47"

If we want to keep the root part we do this (but mind the percent encoding - it is not removed):

let folderWithFilenameAbsoluteString: String? = folderWithFilenameURL.absoluteString
// ▿ Optional<String>
//  - some : "file:///var/mobile/someLongPath/20-01-2017%2022:47"

To manually add the percent encoding for a string:

let folderWithFilenameAndEncoding: String? = folderWithFilename.addingPercentEncoding(withAllowedCharacters: CharacterSet.urlQueryAllowed)
// ▿ Optional<String>
//  - some : "/var/mobile/someLongPath/20-01-2017%2022:47"

To remove the percent encoding:

let folderWithFilenameAbsoluteStringNoEncodig: String? = folderWithFilenameAbsoluteString.removingPercentEncoding
// ▿ Optional<String>
//  - some : "file:///var/mobile/someLongPath/20-01-2017 22:47"

The percent-encoding is important because URLs for network requests need them, while URLs to file system won't always work - it depends on the actual method that uses them. The caveat here is that they may be removed or added automatically, so better debug these conversions carefully.

Answer 3

fileURLWithPath() is used to convert a plain file path (e.g. "/path/to/file") to an URL. Your urlString is a full URL string including the scheme, so you should use

let url = NSURL(string: urlstring)

to convert it back to NSURL. Example:

let urlstring = "file:///Users/Me/Desktop/Doc.txt"
let url = NSURL(string: urlstring)
println("the url = \(url!)")
// the url = file:///Users/Me/Desktop/Doc.txt

Answer 4

In Swift 4 and Swift 3, To convert String to URL:

URL(string: String)

or,

URL.init(string: "yourURLString")

And to convert URL to String:

URL.absoluteString

The one below converts the 'contents' of the url to string

String(contentsOf: URL)