Download a pdf from Firebase and store it locally on iOS - ios

Question

I need to download a pdf from the storage and save it locally on an iOS device, so it can be seen in Files.
Here is the code is taken from the docs, which I'm using:
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
let userID = Auth.auth().currentUser!.uid
print(userID)
// Get a reference to the storage service using the default Firebase App
let storage = Storage.storage()
// Create a storage reference from our storage service
let storageRef = storage.reference()
// Create a reference to the file you want to download
let islandRef = storageRef.child("pdf/sample.pdf")
// Create local filesystem URL
let localURL = URL(string: "pdf/sample.pdf")!
// Download to the local filesystem
let downloadTask = islandRef.write(toFile: localURL) { url, error in
if let error = error {
// Uh-oh, an error occurred!
} else {
// Local file URL for "images/island.jpg" is returned
}
}
}
When I try to run this ViewController, it doesn't crash but throws the following error:
"The file couldn’t be opened because the specified URL type isn’t supported." UserInfo={NSURL=pdf/sample.pdf}
The file in the Firebase Storage is saved in a folder called pdf/sample.pdf. Eventually, I wish to take the reference from the storage and pass it in a RealtimeDatabase, so the user can download it by viewing details about it in a table view.

Answer 1

I think what need to do is to specify in which path to your local filesystem you want to save the downloaded document. So let say you want to use the temporary folder to save your pdf. You can try the following:
let tmporaryDirectoryURL = FileManager.default.temporaryDirectory
let localURL = tmporaryDirectoryURL.appendingPathComponent("sample.pdf")
islandRef.write(toFile: localURL) { url, error in
if let error = error {
print("\(error.localizedDescription)")
} else {
self.presentActivityViewController(withUrl: url)
}
}
Once the file is downloaded in order to save it in the Files app you will need to use UIActivityViewController.
func presentActivityViewController(withUrl url: URL) {
DispatchQueue.main.async {
let activityViewController = UIActivityViewController(activityItems: [url], applicationActivities: nil)
activityViewController.popoverPresentationController?.sourceView = self.view
self.present(activityViewController, animated: true, completion: nil)
}
}
I haven't tested it but my assumption is that you get this error because your localURL variable is not a filesystem URL.

Answer 2

Instead of using URL(string: String) you should be using URL(fileURLWithPath: String) when opening files.