Closing the event stream - detect end_document

[joeppeeters]

I'm trying to use Saxy to convert a streaming XML resource into e SAX event-stream. I'm having a hard time though with closing the document. I wonder if Saxy could help out here.

stream = ["<root>", "<elem>", "text", "</elem>", "</root>"]

{:ok, partial} = Saxy.Partial.new(MyEventHandler, [])

Stream.transform(stream, partial, fn xml_chunk, partial ->
  case Saxy.Partial.parse(partial, xml_chunk) do
    {:cont, partial} ->
      # emit events
      {Enum.reverse(partial.state.user_data), reset_user_data(partial)}
  end
end)
|> Enum.to_list()

# returns something like
[:start_document, :start_element, :start_element, :characters, :end_element,
 :end_element]

As you can see the last emitted event is :end_element (and not :end_document). The stream stops after "</root>", so parsing stops.

My questions:

• Should Saxy detect the end of the document here?
• In which situations would Saxy.Partial.parse return a {:halt, _} response?

---

For now, my alternative solution would be to detect if the stack is empty, and terminate the stream based on that.

Stream.transform(stream, partial, fn
      _, nil ->
        # parsing has been stopped, halt the stream
        {:halt, []}

      xml_chunk, partial ->
        case Saxy.Partial.parse(partial, xml_chunk) do
          {:cont, %{state: %{stack: []}} = partial} ->
            # the stack is empty, so we're done parsing the document: terminate the partial
            {:ok, end_document} = Saxy.Partial.terminate(partial)
            {Enum.reverse(end_document), nil}

          {:cont, partial} ->
            {Enum.reverse(partial.state.user_state), reset_user_state(partial)}

          {:error, error} ->
            raise error
        end
    end)