package multipart_form-lwt

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package multipart_form-lwt
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Streaming API.

val stream : ?bounds:int -> identify:(Multipart_form.Header.t -> 'id) -> string Lwt_stream.t -> Multipart_form.Content_type.t -> [ `Parse of ('id Multipart_form.t, [> `Msg of string ]) Stdlib.result Lwt.t ] * ('id * Multipart_form.Header.t * string Lwt_stream.t) Lwt_stream.t

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.

Non-streaming API.

These functions will store the entire multipart contents in memory, and therefore should not be used when handling possibly large data.

val of_stream_to_list : string Lwt_stream.t -> Multipart_form.Content_type.t -> (int Multipart_form.t * (int * string) list, [> `Msg of string ]) Stdlib.result Lwt.t

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

val of_stream_to_tree : string Lwt_stream.t -> Multipart_form.Content_type.t -> (string Multipart_form.t, [> `Msg of string ]) Stdlib.result Lwt.t

of_stream_to_tree stream content_type returns, if it succeeds, a value Multipart_form.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.