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(*
OCaml HTTP - do it yourself (fully OCaml) HTTP daemon
Copyright (C) <2002-2004> Stefano Zacchiroli <zack@cs.unibo.it>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 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 General Public License for more details.
You should have received a copy of the GNU 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
*)
open Http_types
let m = Mutex.create ()
let m_locked = ref true
let critical f =
Mutex.lock m;
m_locked := true;
Lazy.force f;
m_locked := false;
Mutex.unlock m
(** ocaml's Thread.unlock suspend the invoking process if the mutex is already
* unlocked, therefore we unlock it only if we know that it's currently locked
*)
let safe_unlock _ _ = if !m_locked then Mutex.unlock m
let i = ref 10
let dump_i outchan =
Http_daemon.respond ~body:(Printf.sprintf "i = %d\n" !i) outchan
let callback req outchan =
match req#path with
| "/incr" -> critical (lazy (incr i; dump_i outchan; Unix.sleep 5))
| "/decr" -> critical (lazy (decr i; dump_i outchan; Unix.sleep 5))
| "/get" -> critical (lazy (dump_i outchan))
| bad_request -> Http_daemon.respond_error outchan
let spec =
{ Http_daemon.default_spec with
port = 9999;
mode = `Thread;
callback = callback;
exn_handler = Some safe_unlock;
(** ocaml-http's default exn_handler is Pervasives.ignore. This means
* that threads holding the "m" mutex above may die without unlocking it.
* Using safe_unlock as an exception handler we ensure that "m" mutex is
* unlocked in case of exceptions (e.g. SIGPIPE) *)
}
let _ = Http_daemon.main spec
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