Source file message.ml

(*----------------------------------------------------------------------------
 *  Copyright (c) 2017 Inhabited Type LLC.
 *  Copyright (c) 2019 Antonio N. Monteiro.
 *
 *  All rights reserved.
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions
 *  are met:
 *
 *  1. Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *  2. Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 *  3. Neither the name of the author nor the names of his contributors
 *     may be used to endorse or promote products derived from this software
 *     without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS ``AS IS'' AND ANY EXPRESS
 *  OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 *  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 *  DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE FOR
 *  ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 *  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 *  OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 *  HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 *  STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 *  ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 *  POSSIBILITY OF SUCH DAMAGE.
 *---------------------------------------------------------------------------*)

(* This module contains functionality that applies to both requests and
 * responses, which are collectively referred to in the HTTP 1.1 specifications
 * as 'messages'. *)

let content_length_of_string s =
  match Int64.of_string s with
  | len when Int64.compare len 0L >= 0 -> `Fixed len
  | _ | (exception _) -> `Error `Bad_request

let body_length headers =
  match Headers.get_multi headers "content-length" with
  | [] -> `Unknown
  | [ x ] -> content_length_of_string x
  | hd :: tl ->
    (* if there are multiple content-length headers we require them all to be
     * exactly equal. *)
    if List.for_all (String.equal hd) tl
    then content_length_of_string hd
    else `Unknown