🔴 실시간 채팅 서버 구축 (Erlang)

-module(chat_server).
-export([start/1, init/1]).

-record(state, {pid = none, clients = []}).

start(Port) ->
    {ok, LS} = gen_server:start({local, ?MODULE}, ?MODULE, [Port], []),
    LS.

init([Port]) ->
    { ok, _ } = application:ensure_all_started(inets),
    { ok, _ } = application:ensure_all_started(ssl),
    { ok, _ } = application:ensure_all_started(crypto),
    { ok, _ } = application:ensure_all_started(sasl),

    {ok, Socket} = ssl:listen(Port,
        [ {certfile, "cert.pem"},
          {keyfile, "key.pem"},
          {password, "securepass"},
          {reuseaddr, true},
          {active, false}
        ]),

    spawn_link(fun() -> accept(Socket, #state{pid = self(), clients = []}) end),
    {ok, #state{}}.

accept(Socket, State) ->
    case ssl:wait(Socket, accept) of
        {ok, Pid, _} ->
            spawn_link(fun() -> handle_client(Pid, State) end),
            accept(Socket, State);
        {error, Reason} ->
            error_logger:error_msg("accept failed: ~p~n", [Reason]),
            ok
    end.

handle_client(ClientPid, State) ->
    receive
        {ssl, ClientPid, {data, Bin}} ->
            case parse_message(Bin) of
                {ok, Msg} ->
                    broadcast(Msg, State);
                {error, Reason} ->
                    error_logger:error_msg("메시지 파싱 실패: ~p~n", [Reason])
            end,
        {ssl, ClientPid, closed} ->
            ok;
        _ ->
            handle_client(Client, State)
    end.

parse_message(Bin) ->
    case binary:split(Bin, <<"\r
">>, [global]) of
        [Msg, _] -> {ok, string:trim(Msg)};
        _ -> {error, invalid_format}
    end.

broadcast(Msg, #state{clients = Clients}) ->
    lists:foreach(fun(Client) ->
        ssl:send(Client, <<Msg/binary, "\r
">>)
    end, Clients).

%% 클라이언트 테스트 (erl 쉘에서)
-module(chat_client).
-export([connect/1, send_msg/2]).

connect(Port) ->
    {ok, Socket} = ssl:connect("localhost", Port, [binary, {active, false}]),
    spawn(fun() -> loop(Socket) end),
    ok.

loop(Socket) ->
    receive
        {ssl, Socket, {data, Bin}} ->
            io:format("메시지 수신: ~s~n", [binary_to_list(Bin)]);
        {ssl, Socket, closed} ->
            ok;
        send(Msg) ->
            ssl:send(Socket, <<Msg/binary, "\r
">>),
            loop(Socket)
    end.

send_msg(Socket, Msg) ->
    ssl:send(Socket, <<Msg/binary, "\r
">>).