Source file `body.ml`

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(*{{{ Copyright (c) 2012 Anil Madhavapeddy <anil@recoil.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
  }}}*)

open Cohttp
open Lwt
open Sexplib0.Sexp_conv

type t = [
  | Body.t
  | `Stream of string Lwt_stream.t sexp_opaque
] [@@deriving sexp]

let empty = (Body.empty :> t)

let create_stream fn arg =
  let fin = ref false in
  Lwt_stream.from (fun () ->
    match !fin with
    | true -> return_none
    | false -> begin
        fn arg >>= function
        | Transfer.Done -> return_none
        | Transfer.Final_chunk c ->
          fin := true;
          return (Some c);
        | Transfer.Chunk c -> return (Some c)
      end
  )

let is_empty (body:t) =
  match body with
  | #Body.t as body -> return (Body.is_empty body)
  | `Stream s -> Lwt_stream.is_empty s

let to_string (body:t) =
  match body with
  | #Body.t as body -> return (Body.to_string body)
  |`Stream s ->
    let b = Buffer.create 1024 in
    Lwt_stream.iter (Buffer.add_string b) s >>= fun () ->
    return (Buffer.contents b)

let to_string_list (body:t) =
  match body with
  | #Body.t as body -> return (Body.to_string_list body)
  |`Stream s -> Lwt_stream.to_list s

let of_string s = ((Body.of_string s) :> t)

let to_stream (body:t) =
  match body with
  |`Empty -> Lwt_stream.of_list []
  |`Stream s -> s
  |`String s -> Lwt_stream.of_list [s]
  |`Strings sl -> Lwt_stream.of_list sl

let drain_body (body:t) =
  match body with
  |`Empty
  |`String _
  |`Strings _ -> return_unit
  |`Stream s -> Lwt_stream.junk_while (fun _ -> true) s

let of_string_list l = `Strings l

let of_stream s = `Stream s

let transfer_encoding = function
  |#Body.t as t -> Body.transfer_encoding t
  |`Stream _ -> Transfer.Chunked

(* This will consume the body and return a length, and a
 * new body that should be used instead of the input *)
let length (body:t) : (int64 * t) Lwt.t =
  match body with
  |#Body.t as body -> return (Body.length body, body)
  |`Stream _ ->
    to_string body >>= fun buf ->
    let len = Int64.of_int (String.length buf) in
    return (len, `String buf)

let write_body fn = function
  |`Empty -> return_unit
  |`Stream st -> Lwt_stream.iter_s fn st
  |`String s -> fn s
  |`Strings sl -> Lwt_list.iter_s fn sl

let map f t =
  match t with
  | #Body.t as t -> (Body.map f t :> t)
  | `Stream s -> `Stream (Lwt_stream.map f s)