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@higuoxing
Last active January 30, 2024 13:52
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open Lwt
let listen_addr = Unix.inet_addr_loopback
let port = 5432
(* Shared mutable counter *)
let counter = ref 0
let max_pending_req = 10
let handle_message msg =
match msg with
| "read" -> Printf.sprintf "%s\n" (string_of_int !counter)
| "inc" -> counter := !counter + 1; "Counter is incremented!\n"
| _ -> "Unknown command\n"
let rec handle_conn ic oc () =
Lwt_io.read_line_opt ic >>=
(fun msg ->
match msg with
| Some msg ->
let reply = handle_message msg in
Lwt_io.write oc reply >>= handle_conn ic oc
| None -> Logs_lwt.info (fun m -> m "Connection closed\n") >>= return)
let accept_conn conn =
let fd, _ = conn in
let ic = Lwt_io.of_fd ~mode:Lwt_io.Input fd in
let oc = Lwt_io.of_fd ~mode:Lwt_io.Output fd in
Lwt.on_failure (handle_conn ic oc ()) (fun e -> Logs.err (fun m -> m "%s\n" (Printexc.to_string e)));
Logs_lwt.info (fun m -> m "New connection\n") >>= return
let create_server sock =
let rec serve () =
Lwt_unix.accept sock >>= accept_conn >>= serve
in serve
let create_socket () =
let sock = Lwt_unix.socket Lwt_unix.PF_INET Lwt_unix.SOCK_STREAM 0 in
Lwt_unix.bind sock @@ Lwt_unix.ADDR_INET (listen_addr, port) >>= fun () ->
Lwt_unix.listen sock max_pending_req;
return sock
let () =
Lwt_main.run ((create_socket ()) >>= fun sock ->
let serve = create_server sock in serve ())
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