Working with unmanaged files

Working with unmanaged files is actually pretty similar to doing so with managed files, except that they are not tracked in the database using the File entity type. There is a set of helper functions similar to what we've seen for managed files that can be accessed through the FileSystem service I mentioned earlier. Let's see some examples.

To save a new file, we do almost like we did before with managed files:

$image = file_get_contents('products://tv.jpg'); 
// Load the service statically for quick demonstration. 
$file_system = \Drupal::service('file_system'); 
$path = $file_system->saveData($image, 'public://tv.jpg', FileSystemInterface::EXISTS_REPLACE);  

We load the file data from wherever and use the saveData() method on the service the same way as we did file_save_data(). The difference is that the...