Temporary file path using swift

Question

How to get a unique temporary file path using Swift/Cocoa on OS X? Cocoa does not seem to provide a function for this, only NSTemporaryDirectory() which returns the path of the temporary directory. Using the BSD mktemp function requires a mutable C-string as argument.

Answer 1

Apple has been trying to move away from path-as-string and into NSURL. Here's one way:

Swift 3:

let directory = NSTemporaryDirectory() let fileName = NSUUID().uuidString  // This returns a URL? even though it is an NSURL class method let fullURL = NSURL.fileURL(withPathComponents: [directory, fileName]) 

Swift 2:

let directory = NSTemporaryDirectory() let fileName = NSUUID().UUIDString  let fullURL = NSURL.fileURLWithPathComponents([directory, fileName]) 

Answer 2

Here is a possible method to use mkstemp() from Swift 3 and later. URL methods are used to convert between URL instances and C strings representing the file system path:

// The template string: let template = URL(fileURLWithPath: NSTemporaryDirectory()).appendingPathComponent("file.XXXXXX") as NSURL  // Fill buffer with a C string representing the local file system path.  var buffer = [Int8](repeating: 0, count: Int(PATH_MAX)) template.getFileSystemRepresentation(&buffer, maxLength: buffer.count)  // Create unique file name (and open file): let fd = mkstemp(&buffer) if fd != -1 {      // Create URL from file system string:     let url = URL(fileURLWithFileSystemRepresentation: buffer, isDirectory: false, relativeTo: nil)     print(url.path)  } else {     print("Error: " + String(cString: strerror(errno))) } 

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Older code for Swift 2:

// The template string: let template = NSURL(fileURLWithPath: NSTemporaryDirectory()).URLByAppendingPathComponent("file.XXXXXX")  // Fill buffer with a C string representing the local file system path.  var buffer = [Int8](count: Int(PATH_MAX), repeatedValue: 0) template.getFileSystemRepresentation(&buffer, maxLength: buffer.count)  // Create unique file name (and open file): let fd = mkstemp(&buffer) if fd != -1 {      // Create URL from file system string:     let url = NSURL(fileURLWithFileSystemRepresentation: buffer, isDirectory: false, relativeToURL: nil)     print(url.path!)  } else {     print("Error: " + String(strerror(errno))) }