Source file `response.ml`

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(*{{{ Copyright (c) 2012-2013 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 Sexplib0.Sexp_conv

type t = {
  encoding: Transfer.encoding;
  headers: Header.t;
  version: Code.version;
  status: Code.status_code;
  flush: bool;
} [@@deriving fields, sexp]

let make ?(version=`HTTP_1_1) ?(status=`OK) ?(flush=false) ?(encoding=Transfer.Chunked) ?(headers=Header.init ()) () =
  let encoding =
    match Header.get_transfer_encoding headers with
    | Transfer.(Chunked | Fixed _)  as enc -> enc
    | Unknown -> encoding
  in
  { encoding; headers; version; flush; status }

let pp_hum ppf r =
  Format.fprintf ppf "%s" (r |> sexp_of_t |> Sexplib0.Sexp.to_string_hum)

type tt = t
module Make(IO : S.IO) = struct
  type t = tt
  module IO = IO
  module Header_IO = Header_io.Make(IO)
  module Transfer_IO = Transfer_io.Make(IO)
  type reader = Transfer_IO.reader
  type writer = Transfer_IO.writer

  open IO

  let parse_response_fst_line ic =
    let open Code in
    read_line ic >>= function
    | Some response_line -> begin
      match Stringext.split response_line ~on:' ' with
      | version_raw :: code_raw :: _ -> begin
         match version_of_string version_raw with
         | `HTTP_1_0 | `HTTP_1_1 as v -> return (`Ok (v, (status_of_code (int_of_string code_raw))))
         | `Other _ -> return (`Invalid ("Malformed response version: " ^ version_raw))
      end
      | _ -> return (`Invalid ("Malformed response first line: " ^ response_line))
    end
    | None -> return `Eof

  let read ic =
    parse_response_fst_line ic >>= function
    | `Eof -> return `Eof
    | `Invalid _reason as r -> return r
    | `Ok (version, status) ->
       Header_IO.parse ic >>= fun headers ->
       let encoding = Header.get_transfer_encoding headers in
       let flush = false in
       return (`Ok { encoding; headers; version; status; flush })

  let allowed_body response = (* rfc7230#section-5.7.1 *)
    match status response with
    | #Code.informational_status | `No_content | `Not_modified -> false
    | #Code.status_code -> true

  let has_body response =
    if allowed_body response
    then Transfer.has_body (encoding response)
    else `No

  let make_body_reader {encoding; _} ic = Transfer_IO.make_reader encoding ic
  let read_body_chunk = Transfer_IO.read

  let write_header res oc =
    write oc (Printf.sprintf "%s %s\r\n" (Code.string_of_version res.version)
      (Code.string_of_status res.status)) >>= fun () ->
    let headers =
      if allowed_body res
      then Header.add_transfer_encoding res.headers res.encoding
      else res.headers in
    Header_IO.write headers oc

  let make_body_writer ?flush {encoding; _} oc =
    Transfer_IO.make_writer ?flush encoding oc

  let write_body = Transfer_IO.write

  let write_footer {encoding; _} oc =
    match encoding with
    |Transfer.Chunked ->
       (* TODO Trailer header support *)
       IO.write oc "0\r\n\r\n"
    |Transfer.Fixed _ | Transfer.Unknown -> return ()

  let write ?flush fn req oc =
    write_header req oc >>= fun () ->
    let writer = make_body_writer ?flush req oc in
    fn writer >>= fun () ->
    write_footer req oc
end