How to pass foldername to save file into the folder? - swift3

Question

I was doing download system with the code from https://stackoverflow.com/a/32322851/7789222. It was a great and complete code but I can find a way to pass foldername from view controller to download file to specific folder. Can anyone help me with it please. I am using swift 3 xcode 8.
If I hard code the custom directory in func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didFinishDownloadingTo location: URL) , every file will be downloaded to same folder. I want to pass the foldername from view controller so I can download files to different folder. I cant hardcode because I retrieve file name and foldername from server

Answer 1

The destination URL in the example is given by
let destinationURL = try manager.url(
for: .documentDirectory,
in: .userDomainMask,
appropriateFor: nil,
create: false
).appendingPathComponent(url.lastPathComponent)
(Line 17)
You can just pass a destination folder URL to the initializer of DownloadOperation which replaces the destination URL in the example:
let destinationURL = yourDestinationFolder.appendingPathComponent(url.lastPathComponent)
Your modified DownloadOperation would look something like this:
class DownloadOperation : AsynchronousOperation {
var task: URLSessionTask!
let destinationFolder: URL
init(session: URLSession, url: URL, destinationFolder: URL) {
super.init()
self.destinationFolder = destinationFolder
task = session.downloadTask(with: url) { temporaryURL, response, error in
defer { self.completeOperation() }
guard error == nil && temporaryURL != nil else {
print("\(error)")
return
}
do {
let manager = FileManager.default
let destinationURL = destinationFolder.appendingPathComponent(url.lastPathComponent)
_ = try? manager.removeItem(at: destinationURL) // remove the old one, if any
try manager.moveItem(at: temporaryURL!, to: destinationURL) // move new one there
} catch let moveError {
print("\(moveError)")
}
}
}
...
}
The code for adding operations is then
queue.addOperation(DownloadOperation(session: session, url: url, destinationFolder: destinationFolder))
If you want to use the DownloadManager:
class DownloadManager {
#discardableResult
func addDownload(_ url: URL, to destinationFolder: URL) -> DownloadOperation {
let operation = DownloadOperation(session: session, url: url, destinationFolder: destinationFolder)
operations[operation.task.taskIdentifier] = operation
queue.addOperation(operation)
return operation
}
...
}
The extension:
extension DownloadOperation: URLSessionDownloadDelegate {
func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didFinishDownloadingTo location: URL) {
do {
let manager = FileManager.default
let destinationURL = destinationFolder.appendingPathComponent(downloadTask.originalRequest!.url!.lastPathComponent)
if manager.fileExists(atPath: destinationURL.path) {
try manager.removeItem(at: destinationURL)
}
try manager.moveItem(at: location, to: destinationURL)
} catch {
print("\(error)")
}
}
...
}
Then you can add downloads with
downloadManager.addDownload(url, to: destinationFolder)