fix

apps/iot/src/iot_app.erl

@@ -37,7 +37,7 @@ start_tcp_server() ->
             binary,
             {reuseaddr, true},
             {active, false},
-            {packet, 2},
+            {packet, 4},
             {nodelay, false},
             {backlog, Backlog}
         ]},

apps/iot/src/iot_sup.erl

@@ -27,7 +27,7 @@ start_link() ->
 %%                  modules => modules()}   % optional
 init([]) ->
     SupFlags = #{strategy => one_for_one, intensity => 1000, period => 3600},
-    Specs = [
+    Specs0 = [
         #{
             id => 'iot_device_sup',
             start => {'iot_device_sup', start_link, []},
@@ -47,7 +47,7 @@ init([]) ->
         }
     ],
 
-    {ok, {SupFlags, pools() ++ Specs}}.
+    {ok, {SupFlags, pools() ++ []}}.
 
 %% internal functions
 

apps/iot/src/websocket/tcp_channel.erl

@@ -157,6 +157,13 @@ handle_info({binary, <<?PACKET_PUBLISH_RESPONSE, PacketId:32, Body/binary>>}, St
             {ok, State#state{inflight = NInflight}}
     end;
 
+handle_info({tcp, Socket, Data}, State = #state{transport = Transport, socket = Socket}) ->
+    lager:debug("[ws_channel] socket: ~p, get a message: ~p", [Socket, Data]),
+
+    Transport:send(Socket, <<"hello world reply">>),
+
+    {noreply, State};
+
 handle_info(Info, State) ->
     lager:error("[ws_channel] get a unknown message: ~p, channel will closed", [Info]),
     {stop, State};