Array of multiple URL's NSFileManager Swift - ios

Question

How would I go about adding multiple URL's? I wonder how I can set that up into an array with swift.
if let audioUrl = NSURL(string: "http://freetone.org/ring/stan/iPhone_5-Alarm.mp3") {
println("LOADING AUDIO")
if let myAudioDataFromUrl = NSData(contentsOfURL: audioUrl){
println("AUDIO LOADED")
let documentsUrl = NSFileManager.defaultManager().URLsForDirectory(.DocumentDirectory, inDomains: .UserDomainMask)[0] as NSURL
let destinationUrl = documentsUrl.URLByAppendingPathComponent(audioUrl.lastPathComponent!)
println(destinationUrl)
if NSFileManager().fileExistsAtPath(destinationUrl.path!) {
println("The file already exists at path")
} else {
if myAudioDataFromUrl.writeToURL(destinationUrl, atomically: true) {
println("file saved")
} else {
println("error saving file")
}
}
}
}

Answer 1

In this case I think you should use NSURLSession.sharedSession().dataTaskWithURL to do multiple downloads from your links but keeping the download operation asynchronous. You need to add a callback block to it. You should do as follow:
let documentsUrl = NSFileManager.defaultManager().URLsForDirectory(.DocumentDirectory, inDomains: .UserDomainMask).first as NSURL
let musicArray:[String] = ["http://freetone.org/ring/stan/iPhone_5-Alarm.mp3","http://freetone.org/ring/stan2/Samsung_Galaxy_S4-SMS.mp3","https://www.sounddogs.com/sound-effects/25/mp3/235178_SOUNDDOGS__al.mp3"]
var musicUrls:[NSURL!]!
// create a function to start the audio data download
func getAudioDataFromUrl(audioUrl:NSURL, completion: ((data: NSData?) -> Void)) {
NSURLSession.sharedSession().dataTaskWithURL(audioUrl) { (data, response, error) in
completion(data: data)
}.resume()
}
// create another function to save the audio data
func saveAudioData(audio:NSData, destination:NSURL) -> Bool {
if audio.writeToURL(destination, atomically: true) {
println("The file \"\(destination.lastPathComponent!.stringByDeletingPathExtension)\" was successfully saved.")
return true
}
return false
}
// just convert your links to Urls
func linksToUrls(){
musicUrls = musicArray
.map() { NSURL(string: $0) }
.filter() { $0 != nil }
}
// create a loop to start downloading your urls
func startDownloadingUrls(){
for url in musicUrls {
let destinationUrl = documentsUrl.URLByAppendingPathComponent(url.lastPathComponent!)
if NSFileManager().fileExistsAtPath(destinationUrl.path!) {
println("The file \"\(destinationUrl.lastPathComponent!.stringByDeletingPathExtension)\" already exists at path.")
} else {
println("Started downloading \"\(url.lastPathComponent!.stringByDeletingPathExtension)\".")
getAudioDataFromUrl(url) { data in
dispatch_async(dispatch_get_main_queue()) {
println("Finished downloading \"\(url.lastPathComponent!.stringByDeletingPathExtension)\".")
println("Started saving \"\(url.lastPathComponent!.stringByDeletingPathExtension)\".")
if self.saveAudioData(data!, destination: self.documentsUrl.URLByAppendingPathComponent(url.lastPathComponent!) ) {
// do what ever if writeToURL was successful
} else {
println("The File \"\(url.lastPathComponent!.stringByDeletingPathExtension)\" was not saved.")
}
}
}
}
}
}
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
println("Begin of code")
linksToUrls()
startDownloadingUrls()
println("End of code")
}