From 50ee840220e3d4cb03fb12d47b90d704c0f4ed49 Mon Sep 17 00:00:00 2001
From: DDDHuang <44492639+DDDHuang@users.noreply.github.com>
Date: Tue, 17 Aug 2021 17:49:37 +0800
Subject: [PATCH] feat: add rewrite api (#5502)

---
 apps/emqx_modules/src/emqx_rewrite.erl     | 32 ++++++++---
 apps/emqx_modules/src/emqx_rewrite_api.erl | 66 ++++++++++++++++++++++
 2 files changed, 91 insertions(+), 7 deletions(-)
 create mode 100644 apps/emqx_modules/src/emqx_rewrite_api.erl

diff --git a/apps/emqx_modules/src/emqx_rewrite.erl b/apps/emqx_modules/src/emqx_rewrite.erl
index 20e51ae16..a7e98bbea 100644
--- a/apps/emqx_modules/src/emqx_rewrite.erl
+++ b/apps/emqx_modules/src/emqx_rewrite.erl
@@ -35,12 +35,37 @@
         , disable/0
         ]).
 
+-export([ list/0
+        , update/1]).
+
 %%--------------------------------------------------------------------
 %% Load/Unload
 %%--------------------------------------------------------------------
 
 enable() ->
     Rules = emqx_config:get([rewrite, rules], []),
+    register_hook(Rules).
+
+disable() ->
+    emqx_hooks:del('client.subscribe',   {?MODULE, rewrite_subscribe}),
+    emqx_hooks:del('client.unsubscribe', {?MODULE, rewrite_unsubscribe}),
+    emqx_hooks:del('message.publish',    {?MODULE, rewrite_publish}).
+
+list() ->
+    maps:get(<<"rules">>, emqx_config:get_raw([<<"rewrite">>], #{}), []).
+
+update(Rules0) ->
+    Rewrite = emqx_config:get_raw([<<"rewrite">>], #{}),
+    {ok, Config, _} = emqx_config:update([rewrite], maps:put(<<"rules">>, Rules0, Rewrite)),
+    Rules = maps:get(rules, maps:get(rewrite, Config, #{}), []),
+    case Rules of
+        [] ->
+            disable();
+        _ ->
+            register_hook(Rules)
+    end.
+
+register_hook(Rules) ->
     case Rules =:= [] of
         true -> ok;
         false ->
@@ -50,11 +75,6 @@ enable() ->
             emqx_hooks:put('message.publish',    {?MODULE, rewrite_publish, [PubRules]})
     end.
 
-disable() ->
-    emqx_hooks:del('client.subscribe',   {?MODULE, rewrite_subscribe}),
-    emqx_hooks:del('client.unsubscribe', {?MODULE, rewrite_unsubscribe}),
-    emqx_hooks:del('message.publish',    {?MODULE, rewrite_publish}).
-
 rewrite_subscribe(_ClientInfo, _Properties, TopicFilters, Rules) ->
     {ok, [{match_and_rewrite(Topic, Rules), Opts} || {Topic, Opts} <- TopicFilters]}.
 
@@ -67,7 +87,6 @@ rewrite_publish(Message = #message{topic = Topic}, Rules) ->
 %%--------------------------------------------------------------------
 %% Internal functions
 %%--------------------------------------------------------------------
-
 compile(Rules) ->
     lists:foldl(fun(#{source_topic := Topic,
                       re := Re,
@@ -102,4 +121,3 @@ rewrite(Topic, MP, Dest) ->
                     end, Dest, Vars));
         nomatch -> Topic
     end.
-
diff --git a/apps/emqx_modules/src/emqx_rewrite_api.erl b/apps/emqx_modules/src/emqx_rewrite_api.erl
new file mode 100644
index 000000000..2be28a081
--- /dev/null
+++ b/apps/emqx_modules/src/emqx_rewrite_api.erl
@@ -0,0 +1,66 @@
+-module(emqx_rewrite_api).
+
+-behaviour(minirest_api).
+
+-export([api_spec/0]).
+
+-export([topic_rewrite/2]).
+
+-define(MAX_RULES_LIMIT, 20).
+
+-define(EXCEED_LIMIT, 'EXCEED_LIMIT').
+
+api_spec() ->
+    {[rewrite_api()], []}.
+
+topic_rewrite_schema() ->
+    #{
+        type => object,
+        properties => #{
+            action => #{
+                type => string,
+                description => <<"Node">>,
+                enum => [subscribe, publish]},
+            source_topic => #{
+                type => string,
+                description => <<"Topic">>},
+            re => #{
+                type => string,
+                description => <<"Regular expressions">>},
+            dest_topic => #{
+                type => string,
+                description => <<"Destination topic">>}
+        }
+    }.
+
+rewrite_api() ->
+    Path = "/mqtt/topic_rewrite",
+    Metadata = #{
+        get => #{
+            description => <<"List topic rewrite">>,
+            responses => #{
+                <<"200">> =>
+                    emqx_mgmt_util:response_array_schema(<<"List all rewrite rules">>, topic_rewrite_schema())}},
+        post => #{
+            description => <<"Update topic rewrite">>,
+            'requestBody' => emqx_mgmt_util:request_body_array_schema(topic_rewrite_schema()),
+            response => #{
+                <<"200">> =>
+                    emqx_mgmt_util:response_schema(<<"Update topic rewrite success">>, topic_rewrite_schema()),
+                <<"413">> => emqx_mgmt_util:response_error_schema(<<"Rules count exceed max limit">>, [?EXCEED_LIMIT])}}},
+    {Path, Metadata, topic_rewrite}.
+
+topic_rewrite(get, _Request) ->
+    {200, emqx_rewrite:list()};
+
+topic_rewrite(post, Request) ->
+    {ok, Body, _} = cowboy_req:read_body(Request),
+    Params = emqx_json:decode(Body, [return_maps]),
+    case length(Params) < ?MAX_RULES_LIMIT of
+        true ->
+            ok = emqx_rewrite:update(Params),
+            {200, emqx_rewrite:list()};
+        _ ->
+            Message = list_to_binary(io_lib:format("Max rewrite rules count is ~p", [?MAX_RULES_LIMIT])),
+            {413, #{code => ?EXCEED_LIMIT, message => Message}}
+    end.