chatserver.erl

-module(simple2).
-export([start/0]).
-define(PORT, 33333).

start() ->
    {ok, spawn(fun listener/0)}.

listener() ->
    ChatMaster = spawn(fun() -> chatmaster(dict:new()) end),
    {ok, ListenSocket} = gen_tcp:listen(?PORT, [binary, {active, true}]),
    spawn(fun() -> acceptor(ListenSocket, ChatMaster) end),
    timer:sleep(infinity). % Keep this process alive while listening

acceptor(ListenSocket, ChatMaster) ->
    {ok, _Socket} = gen_tcp:accept(ListenSocket),
    spawn(fun() -> acceptor(ListenSocket, ChatMaster) end),
    WorkerRef = make_ref(),
    WorkerPid = self(),
    ChatMaster ! {worker, WorkerRef, {WorkerPid, "John"}},
    worker(WorkerRef, ChatMaster).

worker(WorkerRef, ChatMaster) ->
    receive
        {tcp, Socket, <<"QUIT", _/binary>>} ->
            ChatMaster ! {quit, WorkerRef},
            gen_tcp:close(Socket),
            worker(WorkerRef, ChatMaster);
        {tcp, Socket, <<"NAME ", name/binary>>} ->
            io:format("Got NAME: ~p~n", [name]),
            gen_tcp:send(Socket, ["Hello ", name, "\r\n"]),
            worker(WorkerRef, ChatMaster);
        {tcp, _Socket, What} ->
            io:format("Got: ~p~n", [What]),
            worker(WorkerRef, ChatMaster)
    after 10000 ->
            io:format("No message in worker ~p~n", [self()]),
            worker(WorkerRef, ChatMaster)
    end.

chatmaster(Workers) ->
    receive
        {worker, WorkerRef, WorkerDetails = {_WorkerPid, _WorkerName}} ->
            WorkersNew = dict:store(WorkerRef, WorkerDetails, Workers),
            chatmaster(WorkersNew);
        {quit, WorkerRef} ->
            {_QuitterPid, QuitterName} = dict:find(WorkerRef, Workers),
            WorkersNew = dict:erase(WorkerRef, Workers),
            dict:map(fun(_K, V = {WorkerPid, _WorkerName}) ->
                         WorkerPid ! {quit, QuitterName},
                         V
                     end, WorkersNew),
            chatmaster(WorkersNew)
    end.