From aab6dcf8d1369ba360b21424054b1ad55c13c952 Mon Sep 17 00:00:00 2001
From: Ery Lee <ery.lee@gmail.com>
Date: Tue, 21 Apr 2015 12:14:27 +0800
Subject: [PATCH] fix issues#101 - access_control for PUBLISH packet should be
 optimized

---
 apps/emqttd/src/emqttd_protocol.erl | 22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/apps/emqttd/src/emqttd_protocol.erl b/apps/emqttd/src/emqttd_protocol.erl
index 592de67e6..a4d50a55e 100644
--- a/apps/emqttd/src/emqttd_protocol.erl
+++ b/apps/emqttd/src/emqttd_protocol.erl
@@ -146,7 +146,7 @@ handle(Packet = ?CONNECT_PACKET(Var), State = #proto_state{peername = Peername =
 
 handle(Packet = ?PUBLISH_PACKET(?QOS_0, Topic, _PacketId, _Payload),
        State = #proto_state{clientid = ClientId, session = Session}) ->
-    case emqttd_access_control:check_acl(client(State), publish, Topic) of
+    case check_acl(publish, Topic, State) of
         allow -> 
             emqttd_session:publish(Session, ClientId, {?QOS_0, emqtt_message:from_packet(Packet)});
         deny -> 
@@ -156,7 +156,7 @@ handle(Packet = ?PUBLISH_PACKET(?QOS_0, Topic, _PacketId, _Payload),
 
 handle(Packet = ?PUBLISH_PACKET(?QOS_1, Topic, PacketId, _Payload),
          State = #proto_state{clientid = ClientId, session = Session}) ->
-    case emqttd_access_control:check_acl(client(State), publish, Topic) of
+    case check_acl(publish, Topic, State) of
         allow -> 
             emqttd_session:publish(Session, ClientId, {?QOS_1, emqtt_message:from_packet(Packet)}),
             send(?PUBACK_PACKET(?PUBACK, PacketId), State);
@@ -167,7 +167,7 @@ handle(Packet = ?PUBLISH_PACKET(?QOS_1, Topic, PacketId, _Payload),
 
 handle(Packet = ?PUBLISH_PACKET(?QOS_2, Topic, PacketId, _Payload),
          State = #proto_state{clientid = ClientId, session = Session}) ->
-    case emqttd_access_control:check_acl(client(State), publish, Topic) of
+    case check_acl(publish, Topic, State) of
         allow -> 
             NewSession = emqttd_session:publish(Session, ClientId, {?QOS_2, emqtt_message:from_packet(Packet)}),
             send(?PUBACK_PACKET(?PUBREC, PacketId), State#proto_state{session = NewSession});
@@ -191,7 +191,7 @@ handle(?PUBACK_PACKET(Type, PacketId), State = #proto_state{session = Session})
 	{ok, NewState};
 
 handle(?SUBSCRIBE_PACKET(PacketId, TopicTable), State = #proto_state{clientid = ClientId, session = Session}) ->
-    AllowDenies = [emqttd_access_control:check_acl(client(State), subscribe, Topic) || {Topic, _Qos} <- TopicTable],
+    AllowDenies = [check_acl(subscribe, Topic, State) || {Topic, _Qos} <- TopicTable],
     case lists:member(deny, AllowDenies) of
         true ->
             %%TODO: return 128 QoS when deny...
@@ -343,6 +343,20 @@ validate_qos(_) -> false.
 try_unregister(undefined, _) -> ok;
 try_unregister(ClientId, _) -> emqttd_cm:unregister(ClientId).
 
+%% publish ACL is cached in process dictionary.
+check_acl(publish, Topic, State) ->
+    case get({acl, publish, Topic}) of
+        undefined ->
+            AllowDeny = emqttd_access_control:check_acl(client(State), publish, Topic),
+            put({acl, publish, Topic}, AllowDeny),
+            AllowDeny;
+        AllowDeny ->
+            AllowDeny
+    end;
+
+check_acl(subscribe, Topic, State) ->
+    emqttd_access_control:check_acl(client(State), subscribe, Topic).
+
 sent_stats(?PACKET(Type)) ->
     emqttd_metrics:inc('packets/sent'), 
     inc(Type).