support keep alive

src/emqtt_client.erl

@@ -26,10 +26,12 @@
                   client_id,
                   clean_sess,
                   will_msg,
-				 awaiting_ack,
-                 subscriptions
+				  keep_alive, 
+				  awaiting_ack,
+                  subscriptions
 			 }).
 
+
 -define(FRAME_TYPE(Frame, Type),
         Frame = #mqtt_frame{ fixed = #mqtt_frame_fixed{ type = Type }}).
 
@@ -97,7 +99,7 @@ handle_info({route, Msg}, #state{socket = Sock} = State) ->
 handle_info({inet_reply, _Ref, ok}, State) ->
     {noreply, State, hibernate};
 
-handle_info({inet_async, Sock, _Ref, {ok, Data}}, #state{ socket = Sock }=State) ->
+handle_info({inet_async, Sock, _Ref, {ok, Data}}, #state{ socket = Sock}=State) ->
     process_received_bytes(
       Data, control_throttle(State #state{ await_recv = false }));
 
@@ -105,13 +107,24 @@ handle_info({inet_async, _Sock, _Ref, {error, Reason}}, State) ->
     network_error(Reason, State);
 
 handle_info({inet_reply, _Sock, {error, Reason}}, State) ->
-	error_logger:info_msg("sock error: ~p~n", [Reason]), 
+	?ERROR("sock error: ~p~n", [Reason]), 
 	{noreply, State};
 
+handle_info(keep_alive_timeout, #state{keep_alive=KeepAlive}=State) ->
+	case emqtt_keep_alive:state(KeepAlive) of
+	idle ->
+		?INFO("keep alive timeout: ~p", [State#state.conn_name]),
+		{stop, normal, State};
+	active ->
+		KeepAlive1 = emqtt_keep_alive:reset(KeepAlive),
+		{noreply, State#state{keep_alive=KeepAlive1}}
+	end;
+
 handle_info(Info, State) ->
 	{stop, {badinfo, Info}, State}.
 
-terminate(_Reason, _State) ->
+terminate(_Reason, #state{keep_alive=KeepAlive}) ->
+	emqtt_keep_alive:cancel(KeepAlive),
 	ok.
 
 code_change(_OldVsn, State, _Extra) ->
@@ -162,8 +175,9 @@ process_received_bytes(Bytes,
     end.
 
 process_frame(Frame = #mqtt_frame{ fixed = #mqtt_frame_fixed{ type = Type }},
-              State ) ->
+              State=#state{keep_alive=KeepAlive}) ->
 	?INFO("~p", [Frame]),
+	emqtt_keep_alive:activate(KeepAlive),
     process_request(Type, Frame, State).
 
 process_request(?CONNECT,
@@ -172,6 +186,7 @@ process_request(?CONNECT,
                                           password   = Password,
                                           proto_ver  = ProtoVersion,
                                           clean_sess = CleanSess,
+										  keep_alive = AlivePeriod,
                                           client_id  = ClientId } = Var}, #state{socket = Sock} = State) ->
     {ReturnCode, State1} =
         case {ProtoVersion =:= ?MQTT_PROTO_MAJOR,
@@ -183,12 +198,14 @@ process_request(?CONNECT,
             _ ->
                 case emqtt_auth:check(Username, Password) of
                     false ->
-                        error_logger:error_msg("MQTT login failed - no credentials~n"),
+                        ?ERROR_MSG("MQTT login failed - no credentials"),
                         {?CONNACK_CREDENTIALS, State};
                     true ->
+						KeepAlive = emqtt_keep_alive:new(AlivePeriod*1500, keep_alive_timeout),
 						{?CONNACK_ACCEPT,
 						 State #state{ will_msg   = make_will_msg(Var),
-											 client_id  = ClientId }}
+											 client_id  = ClientId,
+											 keep_alive = KeepAlive}}
                 end
         end,
 		send_frame(Sock, #mqtt_frame{ fixed    = #mqtt_frame_fixed{ type = ?CONNACK},
@@ -265,9 +282,12 @@ process_request(?UNSUBSCRIBE,
 
     {ok, State #state{ subscriptions = Subs0 }};
 
-process_request(?PINGREQ, #mqtt_frame{}, #state{socket=Sock}=State) ->
+process_request(?PINGREQ, #mqtt_frame{}, #state{socket=Sock, keep_alive=KeepAlive}=State) ->
+	%Keep alive timer
+	KeepAlive1 = emqtt_keep_alive:reset(KeepAlive),
+	?INFO("~p", [KeepAlive1]),
     send_frame(Sock, #mqtt_frame{ fixed = #mqtt_frame_fixed{ type = ?PINGRESP }}),
-    {ok, State};
+    {ok, State#state{keep_alive=KeepAlive1}};
 
 process_request(?DISCONNECT, #mqtt_frame{}, State) ->
     {stop, State}.
@@ -337,3 +357,4 @@ valid_client_id(ClientId) ->
     ClientIdLen = size(ClientId),
     1 =< ClientIdLen andalso ClientIdLen =< ?CLIENT_ID_MAXLEN.
 
+

src/emqtt_keep_alive.erl

@@ -0,0 +1,55 @@
+%% The contents of this file are subject to the Mozilla Public License
+%% Version 1.1 (the "License"); you may not use this file except in
+%% compliance with the License. You may obtain a copy of the License
+%% at http://www.mozilla.org/MPL/
+%%
+%% Software distributed under the License is distributed on an "AS IS"
+%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+%% the License for the specific language governing rights and
+%% limitations under the License.
+%%
+%% Developer of the eMQTT Code is <ery.lee@gmail.com>
+%% Copyright (c) 2012 Ery Lee.  All rights reserved.
+%%
+-module(emqtt_keep_alive).
+
+-export([new/2,
+		state/1,
+		activate/1,
+		reset/1,
+		cancel/1]).
+
+-record(keep_alive, {state, period, timer, msg}).
+
+new(undefined, _) -> 
+	undefined;
+new(0, _) -> 
+	undefined;
+new(Period, TimeoutMsg) when is_integer(Period) ->
+	Ref = erlang:send_after(Period, self(), TimeoutMsg),
+	#keep_alive{state=idle, period=Period, timer=Ref, msg=TimeoutMsg}.
+
+state(undefined) -> 
+	undefined;
+state(#keep_alive{state=State}) ->
+	State.
+
+activate(undefined) -> 
+	undefined; 
+activate(KeepAlive) when is_record(KeepAlive, keep_alive) -> 
+	KeepAlive#keep_alive{state=ative}.
+
+reset(undefined) ->
+	undefined;
+reset(KeepAlive=#keep_alive{period=Period, timer=Timer, msg=Msg}) ->
+	catch erlang:cancel_timer(Timer),
+	Ref = erlang:send_after(Period, self(), Msg),
+	KeepAlive#keep_alive{state=idle, timer = Ref}.
+
+cancel(undefined) -> 
+	undefined;
+cancel(KeepAlive=#keep_alive{timer=Timer}) -> 
+	catch erlang:cancel_timer(Timer),
+	KeepAlive#keep_alive{timer=undefined}.
+
+