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|
(* Ocsigen
* http://www.ocsigen.org
* Module revproxy.ml
* Copyright (C) 2007 Vincent Balat
* Laboratoire PPS - CNRS Universit Paris Diderot
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, with linking exception;
* either version 2.1 of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*)
(** Reverse proxy for Ocsigen *)
(*
The reverse proxy is still experimental because it relies on the
experimental Ocsigen_http_client module.
TODO
- Change the policy for trusted servers for pipelining?
(see ocsigen_http_client.ml)
- add the ability to rewrite some headers from the config file
(for ex after a redirection, the new URL is wrong)
probably in another (filter) extension
- enhance pipelining
- HTTP/1.0
- ...
- Make possible to return for example (Ext_next 404) to allow
other extensions to take the request?
There is a problem if the body contains data (POST request) ...
this data has been sent and is lost ...
*)
open Lwt
open Ocsigen_extensions
open Simplexmlparser
exception Bad_answer_from_http_server
(*****************************************************************************)
(* The table of redirections for each virtual server *)
type redir =
{ regexp: Netstring_pcre.regexp;
full_url: Ocsigen_lib.yesnomaybe;
dest: string;
pipeline: bool;
keephost: bool}
(*****************************************************************************)
(* Finding redirections *)
(** The function that will generate the pages from the request. *)
let gen dir = function
| Ocsigen_extensions.Req_found _ ->
Lwt.return Ocsigen_extensions.Ext_do_nothing
| Ocsigen_extensions.Req_not_found (err, ri) ->
catch
(* Is it a redirection? *)
(fun () ->
Ocsigen_messages.debug2 "--Revproxy: Is it a redirection?";
let dest =
let ri = ri.request_info in
let fi full =
Ocsigen_extensions.find_redirection
dir.regexp
full
dir.dest
ri.ri_ssl
ri.ri_host
ri.ri_server_port
ri.ri_get_params_string
ri.ri_sub_path_string
ri.ri_full_path_string
in
match dir.full_url with
| Ocsigen_lib.Yes -> fi true
| Ocsigen_lib.No -> fi false
| Ocsigen_lib.Maybe ->
try fi false
with Ocsigen_extensions.Not_concerned -> fi true
in
let (https, host, port, uri) =
try
match Ocsigen_lib.parse_url dest with
| (Some https, Some host, port, uri, _, _, _, _) ->
let port = match port with
| None -> if https then 443 else 80
| Some p -> p
in
(https, host, port, uri)
| _ -> raise (Ocsigen_extensions.Error_in_config_file
("Revproxy : error in destination URL "^dest))
(*VVV catch only Neturl exceptions! *)
with e -> raise (Ocsigen_extensions.Error_in_config_file
("Revproxy : error in destination URL "^dest^" - "^
Printexc.to_string e))
in
Ocsigen_messages.debug
(fun () ->
"--Revproxy: YES! Redirection to "^
(if https then "https://" else "http://")^host^":"^
(string_of_int port)^uri);
Ocsigen_lib.get_inet_addr host >>= fun inet_addr ->
(* It is now safe to start next request.
We are sure that the request won't be taken in disorder.
=> We return.
*)
let host =
match
if dir.keephost
then match ri.request_info.ri_host with
| Some h -> Some h
| None -> None
else None
with
| Some h -> h
| None ->
if (not https && port=80) || (https && port=443)
then host
else host^":"^string_of_int port
in
let do_request =
let ri = ri.request_info in
if dir.pipeline then
Ocsigen_http_client.raw_request
~headers:ri.ri_http_frame.Ocsigen_http_frame.frame_header.Ocsigen_http_frame.Http_header.headers
~https
~port
~client:ri.ri_client
~keep_alive:true
~content:ri.ri_http_frame.Ocsigen_http_frame.frame_content
?content_length:ri.ri_content_length
~http_method:ri.ri_method
~host
~inet_addr
~uri ()
else
fun () ->
Ocsigen_http_client.basic_raw_request
~headers:ri.ri_http_frame.Ocsigen_http_frame.frame_header.Ocsigen_http_frame.Http_header.headers
~https
~port
~content:ri.ri_http_frame.Ocsigen_http_frame.frame_content
?content_length:ri.ri_content_length
~http_method:ri.ri_method
~host
~inet_addr
~uri ()
in
Lwt.return
(Ext_found
(fun () ->
do_request ()
>>= fun http_frame ->
let headers =
http_frame.Ocsigen_http_frame.frame_header.Ocsigen_http_frame.Http_header.headers
in
let code =
match
http_frame.Ocsigen_http_frame.frame_header.Ocsigen_http_frame.Http_header.mode
with
| Ocsigen_http_frame.Http_header.Answer code -> code
| _ -> raise Bad_answer_from_http_server
in
match http_frame.Ocsigen_http_frame.frame_content with
| None ->
let empty_result = Ocsigen_http_frame.empty_result () in
let length =
Ocsigen_headers.get_content_length http_frame
in
Lwt.return
{empty_result with
Ocsigen_http_frame.res_content_length = length;
res_headers= headers;
res_stop_stream = http_frame.Ocsigen_http_frame.frame_abort;
res_code= code;
}
| Some stream ->
let default_result =
Ocsigen_http_frame.default_result ()
in
let length =
Ocsigen_headers.get_content_length http_frame
in
Lwt.return
{default_result with
Ocsigen_http_frame.res_content_length = length;
res_stream = (stream, None);
res_stop_stream =
http_frame.Ocsigen_http_frame.frame_abort;
res_headers= headers;
res_code= code;
}
)
)
)
(function
| Not_concerned -> return (Ext_next err)
| e -> fail e)
(*****************************************************************************)
let parse_config = function
| Element ("revproxy", atts, []) ->
let rec parse_attrs ((r, f, d, pipeline, h) as res) = function
| [] -> res
| ("regexp", regexp)::l when r = None -> (* deprecated *)
parse_attrs
(Some (Netstring_pcre.regexp ("^"^regexp^"$")), Ocsigen_lib.Maybe,
d, pipeline, h)
l
| ("fullurl", regexp)::l when r = None ->
parse_attrs
(Some (Netstring_pcre.regexp ("^"^regexp^"$")), Ocsigen_lib.Yes,
d, pipeline, h)
l
| ("suburl", regexp)::l when r = None ->
parse_attrs
(Some (Netstring_pcre.regexp ("^"^regexp^"$")), Ocsigen_lib.No,
d, pipeline, h)
l
| ("dest", dest)::l when d = None ->
parse_attrs
(r, f, Some dest, pipeline, h)
l
| ("keephost", "keephost")::l ->
parse_attrs
(r, f, d, pipeline, true)
l
| ("nopipeline", "nopipeline")::l ->
parse_attrs
(r, f, d, false, h)
l
| (a, _) :: _ ->
badconfig "Wrong or duplicate attribute '%s' for <revproxy>" a
in
let dir =
match parse_attrs (None, Ocsigen_lib.Yes, None, true, false) atts with
| (None, _, _, _, _) ->
badconfig "Missing attribute 'regexp' for <revproxy>"
| (_, _, None, _, _) ->
badconfig "Missing attribute 'dest' for <revproxy>"
| (Some r, full, Some d, pipeline, h) ->
{
regexp=r;
full_url=full;
dest=d;
pipeline=pipeline;
keephost=h;
}
in
gen dir
| Element (t, _, _) -> raise (Bad_config_tag_for_extension t)
| _ -> raise (Error_in_config_file "(revproxy extension) Bad data")
(*****************************************************************************)
(** Registration of the extension *)
let () = register_extension
~name:"revproxy"
~fun_site:(fun _ _ _ _ -> parse_config)
~user_fun_site:(fun _ _ _ _ _ -> parse_config)
~respect_pipeline:true (* We ask ocsigen to respect pipeline order
when sending to extensions! *)
()
|
