Download PDF file and save in document directory

Question

I have the following code that allows me to download a PDF file from a URL, it works correctly:

class ViewController: UIViewController {

    @IBOutlet weak var progressView: UIProgressView!

    override func viewDidLoad() {
        let _ = DownloadManager.shared.activate()
    }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        DownloadManager.shared.onProgress = { (progress) in
            OperationQueue.main.addOperation {
                self.progressView.progress = progress
            }
        }
    }

    override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)
        DownloadManager.shared.onProgress = nil
    }

    @IBAction func startDownload(_ sender: Any) {
        let url = URL(string: "https://d0.awsstatic.com/whitepapers/KMS-Cryptographic-Details.pdf")!
        let task = DownloadManager.shared.activate().downloadTask(with: url)
        task.resume()
    }
}

The file is currently going to: file:///Users/cybermac/Library/Developer/CoreSimulator/Devices/CAEC75D0-423A-4FB2-B0D6-9E7CADB190A1/data/Containers/Data/Application/8B5CBFC8-7058-48DB-A1C4-872302A80610/Library/Caches/com.apple.nsurlsessiond/Downloads/com.example.DownloadTaskExample/CFNetworkDownload_Q7OVlf.tmp

How do I save it in /Documents/?

Something like this: file:///Users/cybermac/Library/Developer/CoreSimulator/Devices/CAEC75D0-423A-4FB2-B0D6-9E7CADB190A1/data/Containers/Data/Application/64370B29-2C01-470F-AE76-17EF1A7BC918/Documents/

The idea is that the file saved in that directory can be used to read it offline (with PDFKit or webKit). It will only be deleted if the application is deleted.

Answer 1

You need to move the file to your custom location after the download. Implement URLSessionDownloadDelegate and you will receive the location of your downloaded file.

Delegate method:

func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didFinishDownloadingTo location: URL)

Code to move the file:

do {
    let documentsURL = try
        FileManager.default.url(for: .documentDirectory,
                                in: .userDomainMask,
                                appropriateFor: nil,
                                create: false)

    let savedURL = documentsURL.appendingPathComponent("yourCustomName.pdf")
    try FileManager.default.moveItem(at: location, to: savedURL)
} catch {
    print ("file error: \(error)")
}

To learn more refer to this repo.