rewrite

apps/emqttd/src/emqttd_mod_rewrite.erl

@@ -29,6 +29,8 @@
 
 -author("Feng Lee <feng@emqtt.io>").
 
+-include_lib("emqtt/include/emqtt.hrl").
+
 -behaviour(emqttd_gen_mod).
 
 -export([load/1, reload/1, unload/1]).
@@ -50,20 +52,33 @@ load(Opts) ->
     emqttd_broker:hook(client_publish, {?MODULE, rewrite_publish},
                        {?MODULE, rewrite_publish, [publish, Sections]}).
 
-rewrite(TopicTable, [subscribe, _Sections]) ->
-    lager:info("Rewrite Subscribe: ~p", [TopicTable]),
-    TopicTable;
+rewrite(TopicTable, [subscribe, Sections]) ->
+    [{match_topic(Topic, Sections), Qos} || {Topic, Qos} <- TopicTable];
 
-rewrite(Topics, [unsubscribe, _Sections]) ->
-    lager:info("Rewrite Unsubscribe: ~p", [Topics]),
-    Topics;
+rewrite(Topics, [unsubscribe, Sections]) ->
+    [match_topic(Topic, Sections) || Topic <- Topics];
 
-rewrite(Message, [publish, _Sections]) ->
-    Message.
+rewrite(Message=#mqtt_message{topic = Topic}, [publish, Sections]) ->
+    %%TODO: this will not work if the client is always online.
+    RewriteTopic =
+    case get({rewrite, Topic}) of
+        undefined ->
+            DestTopic = match_topic(Topic, Sections),
+            put({rewrite, Topic}, DestTopic), DestTopic;
+        DestTopic ->
+            DestTopic
+        end,
+    Message#mqtt_message{topic = RewriteTopic}.
 
 reload(File) ->
     %%TODO: The unload api is not right...
-    unload(state), load([{file, File}]).
+    case emqttd:is_mod_enabled(rewrite) of
+        true -> 
+            unload(state),
+            load([{file, File}]);
+        false ->
+            {error, module_unloaded}
+    end.
             
 unload(_) ->
     emqttd_broker:unhook(client_subscribe, {?MODULE, rewrite_subscribe}),
@@ -81,3 +96,27 @@ compile(Sections) ->
     end,
     [{topic, Topic, [C(R) || R <- Rules]} || {topic, Topic, Rules} <- Sections].
 
+match_topic(Topic, []) ->
+    Topic;
+match_topic(Topic, [{topic, Filter, Rules}|Sections]) ->
+    case emqtt_topic:match(Topic, Filter) of
+        true ->
+            match_rule(Topic, Rules);
+        false ->
+            match_topic(Topic, Sections)
+    end.
+
+match_rule(Topic, []) ->
+    Topic;
+match_rule(Topic, [{rewrite, MP, Dest}|Rules]) ->
+    case re:run(Topic, MP, [{captrue, all_but_first, list}]) of
+        {match, Captured} ->
+            %%TODO: stupid??? how to replace $1, $2?
+            Vars = lists:zip(["\\$" ++ integer_to_list(I) || I <- lists:seq(1, length(Captured))], Captured),
+            iolist_to_binary(lists:foldl(
+                    fun({Var, Val}, Acc) ->
+                            re:replace(Acc, Var, Val, [global])
+                    end, Dest, Vars));
+        nomatch ->
+            match_rule(Topic, Rules)
+    end.