-module(generic_proxy).

-export([run/0]).

-define(PORT_FROM, 63790). -define(PORT_TO, 6379). -define(BACKLOG, 10000).

run() -> {ok, Socket} = gen_tcp:listen(0, [ {backlog, ?BACKLOG}, {reuseaddr, true}, {port, ?PORT_FROM}, binary, {packet, 0}, {active, true} ]), accept(Socket).

accept(Socket) -> {ok, ClientSocket} = gen_tcp:accept(Socket), Handler = spawn(fun() -> receive go -> go end, {ok, TargetSocket} = gen_tcp:connect("127.0.0.1", ?PORT_TO, [ binary, {nodelay, true}, {packet, 0}, {active, true} ]), loop(TargetSocket, ClientSocket) end), gen_tcp:controlling_process(ClientSocket, Handler), Handler ! go, accept(Socket).

loop(TargetSocket, ClientSocket) -> Continue = receive {tcp, TargetSocket, Data} -> gen_tcp:send(ClientSocket, Data), true; {tcp, ClientSocket, Data} -> gen_tcp:send(TargetSocket, Data), true; {tcp_closed, _} -> gen_tcp:close(TargetSocket), gen_tcp:close(ClientSocket), false; X -> io:format("Unknown msg: ~p", [X]), gen_tcp:close(TargetSocket), gen_tcp:close(ClientSocket), false end, case Continue of true -> loop(TargetSocket, ClientSocket); false -> ok end.