let url = "https://path-to-media"
guard let documentsUrl = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first,
      let searchQuery = url.absoluteString.components(separatedBy: "/").last else {
  return nil
}

do {
  let directoryContents = try FileManager.default.contentsOfDirectory(at: documentsUrl, includingPropertiesForKeys: nil, options: [])
  let cachedFiles = directoryContents.filter { $0.absoluteString.contains(searchQuery) }
  
  // do something with the files found by the url
} catch {
  // Could not find any files
}

let url = "https://path-to-media"
let request = URLRequest(url: url)
let downloadTask = URLSession.shared.downloadTask(with: request) { (location, response, error) in
  guard let location = location,
        let response = response,
        let documentsPath = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true).first else {
    return
  }
  let documentsDirectoryUrl = URL(fileURLWithPath: documentsPath)
  let documentUrl = documentsDirectoryUrl.appendingPathComponent(response.suggestedFilename)
  let _ = try? FileManager.default.moveItem(at: location, to: documentUrl)

  // documentUrl is the local URL which we just downloaded and saved to the FileManager
}.resume()