%% Feel free to use, reuse and abuse the code in this file.
-module(reverse_protocol).
-behaviour(gen_server).
-behaviour(ranch_protocol).
-export([start_link/4]).
-export([init/1, init/4, handle_call/3, handle_cast/2, handle_info/2,
terminate/2, code_change/3]).
-export([reverse_binary/1]).
-define(TIMEOUT, 5000).
-record(state, {socket, transport}).
reverse_binary(B) when is_binary(B) ->
[list_to_binary(
lists:reverse(
binary_to_list(binary:part(B, {0, byte_size(B)-2})))),
"\r\n"].
start_link(Ref, Socket, Transport, Opts) ->
proc_lib:start_link(?MODULE, init, [Ref, Socket, Transport, Opts]).
init(Args) ->
{ok, Args}.
init(Ref, Socket, Transport, _Opts = []) ->
ok = proc_lib:init_ack({ok, self()}),
ok = ranch:accept_ack(Ref),
ok = Transport:setopts(Socket, [{active, once}]),
gen_server:enter_loop(?MODULE,[], {state, Socket, Transport},?TIMEOUT).
handle_info({tcp, Socket, Data}, #state{transport = Transport} = State) ->
inet:setopts(State#state.socket, [{active, once}]),
Transport:send(Socket, reverse_binary(Data)),
{noreply, State, ?TIMEOUT};
handle_info({tcp_closed, _Socket}, State) ->
{stop, normal, State};
handle_info({tcp_error, _, Reason}, State) ->
{stop, Reason, State};
handle_info(timeout, State) ->
{stop, normal, State};
handle_info(_Info, State) ->
{stop, normal, State}.
handle_call(_Request, _From, State) ->
{reply, ok, State}.
handle_cast(_Msg, State) ->
{noreply, State}.
terminate(_Reason, _State) ->
ok.
code_change(_OldVsn, State, _Extra) ->
{ok, State}.