Parse and import configuration URL from picker

CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+### Added
+
+- Import host via document picker.
+
 ### Changed
 
 - Upgrade project to Xcode 11.

Passepartout-iOS/Scenes/Organizer/ImportedHostsViewController.swift

@@ -72,6 +72,8 @@ class ImportedHostsViewController: UITableViewController {
     
     @IBAction private func openConfigurationFile() {
         let picker = UIDocumentPickerViewController(documentTypes: ["public.content", "public.data"], in: .import)
+        picker.allowsMultipleSelection = false
+        picker.delegate = self
         present(picker, animated: true, completion: nil)
     }
     
@@ -88,7 +90,7 @@ class ImportedHostsViewController: UITableViewController {
         return true
     }
     
-    private func tryParseURL(_ url: URL, cell: UITableViewCell) -> Bool {
+    private func tryParseURL(_ url: URL, cell: UITableViewCell?) -> Bool {
         deselectSelectedRow()
 
         importer = HostImporter(withConfigurationURL: url, parentViewController: self)
@@ -143,3 +145,15 @@ extension ImportedHostsViewController {
         tableView.deleteRows(at: [indexPath], with: .top)
     }
 }
+
+extension ImportedHostsViewController: UIDocumentPickerDelegate {
+    func documentPickerWasCancelled(_ controller: UIDocumentPickerViewController) {
+    }
+    
+    func documentPicker(_ controller: UIDocumentPickerViewController, didPickDocumentsAt urls: [URL]) {
+        guard let url = urls.first else {
+            return
+        }
+        _ = tryParseURL(url, cell: nil)
+    }
+}