Routing in cowboy

test.erl

start(_Type, _Args) ->
  Dispatch = [
    {'_', [
      {[<<"users">>, id, <<"messages">>], users_handler, []},
      {'_', default_handler, []}
    ]}
  ],
  cowboy:start_listener(http, 100,
  cowboy_tcp_transport, [{port, 8080}],
  cowboy_http_protocol, [{dispatch, Dispatch}]
),

Then in users_handler.erl,

handle(Req, State) ->
  {Value, Req2} = cowboy_http_req:binding(id, Req),
  case Value of 
    <<"messages">> ->      
      {ok, Req3} = cowboy_http_req:reply(200, [], <<"Hello world!">>, Req),
      {ok, Req3, State},
    _ ->
      ...
  end.