stream ~identify src content_type returns:

• a promise th about the parser
• a stream stream of parts

They can be manipulated with Lwt.both, and, by this way, ensure a real stream between the parser th and the process which saves parts.

Assume that you have a function to save a Lwt_stream.t into a filename:

  val save_part : filename:string -> Header.t -> string Lwt_stream.t ->
    unit Lwt.t

You can use it with stream like:

  let identify _ : string = random_unique_filename () in
  let `Parse th, stream = stream ~identify src content_type in
  let rec saves () = Lwt_stream.get stream >>= function
    | None -> Lwt.return_unit
    | Some (filename, hdr, contents) ->
      save_part ~filename hdr contents >>= fun () ->
      saves () in
  Lwt.both th (saves ()) >>= fun (res, ()) -> Lwt.return res

By this way, as long as we parse src, at the same time, we save parts into filenames. Finally, we return the multipart/form structure with a mapping between temporary files and parts.

Similar to Multipart_form.of_stream_to_list, but consumes a Lwt_stream.t.

of_stream_to_tree stream content_type returns, if it succeeds, a value t representing the multipart document, where the contents of the parts are stored as strings. It is equivalent to of_stream_to_list where references have been replaced with their associated contents.