Opening a PDF with UIDocumentInteractionController URL error

Question

The app needs to create a URL to pass into a UIDocumentInteractionController that will present the user with options to share the file. It's a PDF that is downloaded over the network and confirmed as being in place.

let documentsPath = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
let filePath = documentsPath.appendingPathComponent("documents/\(self.filename!)").path
let fileURL = URL(fileURLWithPath: filePath)

This is where the PDF is stored after being downloaded.

let documentController: UIDocumentInteractionController = UIDocumentInteractionController.init(url: fileURL)
documentController.uti = "com.adobe.pdf"
documentController.presentOpenInMenu(from: CGRect(x: 0, y: 0, width: self.container.frame.width, height: self.container.frame.height), in: self.container, animated: true)

This opens up the menu with the sharing options but when trying to select an app to open the PDF, the following error occurs:

Could not instantiate class NSURL. Error: Error Domain=NSCocoaErrorDomain Code=4864 "The URL archive of type “public.url” contains invalid data." UserInfo={NSDebugDescription=The URL archive of type “public.url” contains invalid data.}

After having confirmed the document is where it should be, when printing the fileURL, it's the following:

file:///var/mobile/Containers/Data/Application/3296B736-4DFB-4F62-9B05-C800D574982B/Documents/documents/77351848-68816600-1626168959.pdf

I have searched high and low for an answer to this and I believe it's more linked to the URL than the UIDocumentInteractionController itself.

Any advice would be enormously appreciated.

Answer 1

Swift 5 Implementation(Xcode 12.5):

class VC1: UIViewController {
    
    var pdfURL: URL?
    var documentInteractionController:UIDocumentInteractionController!
    
    override func viewDidLoad() {
        super.viewDidLoad()
    }
    
    @IBAction func downloadAction(_ sender: Any) {
        self.downloadPDF()
    }
    
    func downloadPDF() {
        guard let url = URL(string: "https://file-examples-com.github.io/uploads/2017/10/file-sample_150kB.pdf") else { return }
        
        let urlSession = URLSession(configuration: .default, delegate: self, delegateQueue: OperationQueue())
        
        let downloadTask = urlSession.downloadTask(with: url)
        downloadTask.resume()
    }
    
    func showPDF(url: URL) {
        documentInteractionController = UIDocumentInteractionController(url: url)
        documentInteractionController.delegate = self
        
        DispatchQueue.main.async { [self] in
            documentInteractionController.presentPreview(animated: true)
        }
    }
}

extension VC1: UIDocumentInteractionControllerDelegate {
    func documentInteractionControllerViewControllerForPreview(_ controller: UIDocumentInteractionController) -> UIViewController {
           return self
       }
    
    func documentInteractionControllerDidEndPreview(_ controller: UIDocumentInteractionController) {
        print("Dismissed!!!")
        documentInteractionController = nil
    }
}

extension VC1:  URLSessionDownloadDelegate {
    func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didFinishDownloadingTo location: URL) {
        guard let url = downloadTask.originalRequest?.url else { return }
        let documentsPath = FileManager.default.urls(for: .cachesDirectory, in: .userDomainMask)[0]
        let destinationURL = documentsPath.appendingPathComponent(url.lastPathComponent)
        try? FileManager.default.removeItem(at: destinationURL)
        do {
            try FileManager.default.copyItem(at: location, to: destinationURL)
            self.pdfURL = destinationURL
            showPDF(url: destinationURL)
        } catch let error {
            print("Error: \(error.localizedDescription)")
        }
    }
}