From 8ec14bb07eb4481225096d4cb14b183d0f41673c Mon Sep 17 00:00:00 2001
From: Paulo Zulato <paulozulato@gmail.com>
Date: Mon, 24 Jul 2023 16:00:34 -0300
Subject: [PATCH] fix(topic_rewrite): handle error when target contains
 wildcards

Fixes https://emqx.atlassian.net/browse/EMQX-10565
---
 apps/emqx_modules/src/emqx_rewrite_api.erl    | 28 +++++++++++++++++--
 .../test/emqx_rewrite_api_SUITE.erl           |  2 +-
 changes/ce/fix-11337.en.md                    |  1 +
 rel/i18n/emqx_rewrite_api.hocon               |  5 ++++
 4 files changed, 33 insertions(+), 3 deletions(-)
 create mode 100644 changes/ce/fix-11337.en.md

diff --git a/apps/emqx_modules/src/emqx_rewrite_api.erl b/apps/emqx_modules/src/emqx_rewrite_api.erl
index cf22daec6..4cf65da8e 100644
--- a/apps/emqx_modules/src/emqx_rewrite_api.erl
+++ b/apps/emqx_modules/src/emqx_rewrite_api.erl
@@ -28,6 +28,7 @@
 -define(MAX_RULES_LIMIT, 20).
 
 -define(EXCEED_LIMIT, 'EXCEED_LIMIT').
+-define(BAD_REQUEST, 'BAD_REQUEST').
 
 api_spec() ->
     emqx_dashboard_swagger:spec(?MODULE).
@@ -62,6 +63,10 @@ schema("/mqtt/topic_rewrite") ->
                     hoconsc:array(hoconsc:ref(emqx_modules_schema, "rewrite")),
                     #{desc => ?DESC(update_topic_rewrite_api)}
                 ),
+                400 => emqx_dashboard_swagger:error_codes(
+                    [?BAD_REQUEST],
+                    ?DESC(update_topic_rewrite_api_response400)
+                ),
                 413 => emqx_dashboard_swagger:error_codes(
                     [?EXCEED_LIMIT],
                     ?DESC(update_topic_rewrite_api_response413)
@@ -75,11 +80,30 @@ topic_rewrite(get, _Params) ->
 topic_rewrite(put, #{body := Body}) ->
     case length(Body) < ?MAX_RULES_LIMIT of
         true ->
-            ok = emqx_rewrite:update(Body),
-            {200, emqx_rewrite:list()};
+            try
+                ok = emqx_rewrite:update(Body),
+                {200, emqx_rewrite:list()}
+            catch
+                throw:#{
+                    kind := validation_error,
+                    reason := #{
+                        msg := "cannot_use_wildcard_for_destination_topic",
+                        invalid_topics := InvalidTopics
+                    }
+                } ->
+                    Message = get_invalid_wildcard_topic_msg(InvalidTopics),
+                    {400, #{code => ?BAD_REQUEST, message => Message}}
+            end;
         _ ->
             Message = iolist_to_binary(
                 io_lib:format("Max rewrite rules count is ~p", [?MAX_RULES_LIMIT])
             ),
             {413, #{code => ?EXCEED_LIMIT, message => Message}}
     end.
+
+get_invalid_wildcard_topic_msg(InvalidTopics) ->
+    iolist_to_binary(
+        io_lib:format("Cannot use wildcard for destination topic. Invalid topics: ~p", [
+            InvalidTopics
+        ])
+    ).
diff --git a/apps/emqx_modules/test/emqx_rewrite_api_SUITE.erl b/apps/emqx_modules/test/emqx_rewrite_api_SUITE.erl
index 6c65d351b..96d590b5c 100644
--- a/apps/emqx_modules/test/emqx_rewrite_api_SUITE.erl
+++ b/apps/emqx_modules/test/emqx_rewrite_api_SUITE.erl
@@ -130,7 +130,7 @@ t_mqtt_topic_rewrite_wildcard(_) ->
     lists:foreach(
         fun(Rule) ->
             ?assertMatch(
-                {ok, 500, _},
+                {ok, 400, _},
                 request(
                     put,
                     uri(["mqtt", "topic_rewrite"]),
diff --git a/changes/ce/fix-11337.en.md b/changes/ce/fix-11337.en.md
new file mode 100644
index 000000000..c695cb87f
--- /dev/null
+++ b/changes/ce/fix-11337.en.md
@@ -0,0 +1 @@
+Fix HTTP API error when a publish topic rewrite rule targets a topic with wildcards. Now it returns error 400 (Bad Match) instead of error 500 (Internal Error).
diff --git a/rel/i18n/emqx_rewrite_api.hocon b/rel/i18n/emqx_rewrite_api.hocon
index 1b56cf24d..58b7af0cd 100644
--- a/rel/i18n/emqx_rewrite_api.hocon
+++ b/rel/i18n/emqx_rewrite_api.hocon
@@ -15,4 +15,9 @@ update_topic_rewrite_api_response413.desc:
 update_topic_rewrite_api_response413.label:
 """Rules count exceed limit"""
 
+update_topic_rewrite_api_response400.desc:
+"""Bad request"""
+update_topic_rewrite_api_response400.label:
+"""Bad request"""
+
 }