iosiphoneswiftipadnsurlsessiondownloadtask

Swift - Downloading video with downloadTaskWithURL


I'm downloading a video thanks to downloadTaskWithURL and I'm saving it to my gallery with this code :

    func saveVideoBis(fileStringURL:String){

    print("saveVideoBis");

    let url = NSURL(string: fileStringURL);
    (NSURLSession.sharedSession().downloadTaskWithURL(url!) { (location:NSURL?, r:NSURLResponse?, e:NSError?) -> Void in

        let mgr = NSFileManager.defaultManager()

        let documentsPath = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)[0];

        print(documentsPath);

        let destination = NSURL(string: NSString(format: "%@/%@", documentsPath, url!.lastPathComponent!) as String);

        print(destination);

        try? mgr.moveItemAtPath(location!.path!, toPath: destination!.path!)

        PHPhotoLibrary.requestAuthorization({ (a:PHAuthorizationStatus) -> Void in
            PHPhotoLibrary.sharedPhotoLibrary().performChanges({
                PHAssetChangeRequest.creationRequestForAssetFromVideoAtFileURL(destination!);
                }) { completed, error in
                    if completed {
                        print(error);
                        print("Video is saved!");
                        self.sendNotification();
                    }
            }
        })
    }).resume()
}

It works perfectly fine on my simulator but on my iPad the video isn't saved even if the print("Video is saved!"); appears. Do you have any idea why ?

I also have that message appearing in my console

Unable to create data from file (null)


Solution

  • Please check comments through the code:

    Xcode 8 • Swift 3

    import UIKit
    import Photos
    
    class ViewController: UIViewController {
    
        func downloadVideoLinkAndCreateAsset(_ videoLink: String) {
    
            // use guard to make sure you have a valid url
            guard let videoURL = URL(string: videoLink) else { return }
    
            guard let documentsDirectoryURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first else { return }
    
            // check if the file already exist at the destination folder if you don't want to download it twice
            if !FileManager.default.fileExists(atPath: documentsDirectoryURL.appendingPathComponent(videoURL.lastPathComponent).path) {
    
                // set up your download task
                URLSession.shared.downloadTask(with: videoURL) { (location, response, error) -> Void in
    
                    // use guard to unwrap your optional url
                    guard let location = location else { return }
    
                    // create a deatination url with the server response suggested file name
                    let destinationURL = documentsDirectoryURL.appendingPathComponent(response?.suggestedFilename ?? videoURL.lastPathComponent)
    
                    do {
    
                        try FileManager.default.moveItem(at: location, to: destinationURL)
    
                        PHPhotoLibrary.requestAuthorization({ (authorizationStatus: PHAuthorizationStatus) -> Void in
    
                            // check if user authorized access photos for your app
                            if authorizationStatus == .authorized {
                                PHPhotoLibrary.shared().performChanges({
                                    PHAssetChangeRequest.creationRequestForAssetFromVideo(atFileURL: destinationURL)}) { completed, error in
                                        if completed {
                                            print("Video asset created")
                                        } else {
                                            print(error)
                                        }
                                }
                            }
                        })
    
                    } catch { print(error) }
    
                }.resume()
    
            } else {
                print("File already exists at destination url")
            }
    
        }
    
        override func viewDidLoad() {
            super.viewDidLoad()
            downloadVideoLinkAndCreateAsset("https://www.yourdomain.com/yourmovie.mp4")
        }
    
    }