fix(coap): remove the leading `/` in assembling publish topic

apps/emqx_gateway/src/coap/emqx_coap_channel.erl

@@ -153,7 +153,7 @@ init(
             mountpoint => Mountpoint
         }
     ),
-
+    %% FIXME: it should coap.hearbeat instead of idle_timeout?
     Heartbeat = ?GET_IDLE_TIME(Config),
     #channel{
         ctx = Ctx,
@@ -447,6 +447,7 @@ enrich_conninfo(
         conninfo = ConnInfo
     }
 ) ->
+    %% FIXME: generate a random clientid if absent
     case Queries of
         #{<<"clientid">> := ClientId} ->
             Interval = maps:get(interval, emqx_keepalive:info(KeepAlive)),
@@ -467,6 +468,9 @@ enrich_clientinfo(
     {Queries, Msg},
     Channel = #channel{clientinfo = ClientInfo0}
 ) ->
+    %% FIXME:
+    %% 1. generate a random clientid if absent;
+    %% 2. assgin username, password to `undefined` if absent
     case Queries of
         #{
             <<"username">> := UserName,
@@ -542,6 +546,7 @@ process_connect(
         )
     of
         {ok, _Sess} ->
+            %% FIXME: Token in cluster wide?
             RandVal = rand:uniform(?TOKEN_MAXIMUM),
             Token = erlang:list_to_binary(erlang:integer_to_list(RandVal)),
             NResult = Result#{events => [{event, connected}]},

apps/emqx_gateway/src/coap/handler/emqx_coap_pubsub_handler.erl

@@ -69,17 +69,7 @@ handle_method(_, _, Msg, _, _) ->
 check_topic([]) ->
     error;
 check_topic(Path) ->
-    Sep = <<"/">>,
-    {ok,
-        emqx_http_lib:uri_decode(
-            lists:foldl(
-                fun(Part, Acc) ->
-                    <<Acc/binary, Sep/binary, Part/binary>>
-                end,
-                <<>>,
-                Path
-            )
-        )}.
+    {ok, emqx_http_lib:uri_decode(iolist_to_binary(lists:join(<<"/">>, Path)))}.
 
 get_sub_opts(#coap_message{options = Opts} = Msg) ->
     SubOpts = maps:fold(fun parse_sub_opts/3, #{}, Opts),
@@ -124,6 +114,10 @@ get_publish_qos(Msg) ->
     end.
 
 apply_publish_opts(Msg, MQTTMsg) ->
+    case emqx_coap_message:get_option(uri_query, Msg) of
+        undefined ->
+            MQTTMsg;
+        Qs ->
             maps:fold(
                 fun
                     (<<"retain">>, V, Acc) ->
@@ -141,8 +135,9 @@ apply_publish_opts(Msg, MQTTMsg) ->
                         Acc
                 end,
                 MQTTMsg,
-        emqx_coap_message:get_option(uri_query, Msg)
-    ).
+                Qs
+            )
+    end.
 
 subscribe(#coap_message{token = <<>>} = Msg, _, _, _) ->
     reply({error, bad_request}, <<"observe without token">>, Msg);