From f87bef9ffb33fd32a1e4cbb534f46f2fce8b78b1 Mon Sep 17 00:00:00 2001
From: JianBo He <heeejianbo@163.com>
Date: Thu, 29 Jul 2021 09:13:55 +0800
Subject: [PATCH] feat(gw-stomp): run subscribe hooks

---
 apps/emqx_gateway/src/emqx_gateway_utils.erl  |  8 ++
 .../src/stomp/emqx_stomp_channel.erl          | 98 ++++++++++++++-----
 2 files changed, 82 insertions(+), 24 deletions(-)

diff --git a/apps/emqx_gateway/src/emqx_gateway_utils.erl b/apps/emqx_gateway/src/emqx_gateway_utils.erl
index 8adf06249..74bc3a8ce 100644
--- a/apps/emqx_gateway/src/emqx_gateway_utils.erl
+++ b/apps/emqx_gateway/src/emqx_gateway_utils.erl
@@ -43,6 +43,7 @@
 
 -export([ default_tcp_options/0
         , default_udp_options/0
+        , default_subopts/0
         ]).
 
 -define(ACTIVE_N, 100).
@@ -186,3 +187,10 @@ default_tcp_options() ->
 
 default_udp_options() ->
     [binary].
+
+default_subopts() ->
+    #{rh  => 0, %% Retain Handling
+      rap => 0, %% Retain as Publish
+      nl  => 0, %% No Local
+      qos => 0  %% QoS
+     }.
diff --git a/apps/emqx_gateway/src/stomp/emqx_stomp_channel.erl b/apps/emqx_gateway/src/stomp/emqx_stomp_channel.erl
index e0fb4b82e..6c1d678e1 100644
--- a/apps/emqx_gateway/src/stomp/emqx_stomp_channel.erl
+++ b/apps/emqx_gateway/src/stomp/emqx_stomp_channel.erl
@@ -373,34 +373,36 @@ handle_in(?PACKET(?CMD_SUBSCRIBE, Headers),
           Channel = #channel{
                        ctx = Ctx,
                        subscriptions = Subs,
-                       clientinfo = ClientInfo = #{mountpoint := Mountpoint}
+                       clientinfo = ClientInfo
                       }) ->
+
     SubId = header(<<"id">>, Headers),
     Topic = header(<<"destination">>, Headers),
     Ack   = header(<<"ack">>, Headers, <<"auto">>),
-
-    MountedTopic = emqx_mountpoint:mount(Mountpoint, Topic),
-
-    case lists:keyfind(SubId, 1, Subs) of
-        {SubId, MountedTopic, Ack} ->
-            maybe_outgoing_receipt(receipt_id(Headers), Channel);
-        {SubId, _OtherTopic, _OtherAck} ->
-            %% FIXME:
-            ?LOG(error, "Conflicts with subscribed topics ~s, id: ~s",
-                        [_OtherTopic, SubId]),
-            ErrMsg = "Conflict subscribe id ",
-            handle_out(error, {receipt_id(Headers), ErrMsg}, Channel);
-        false ->
-            case emqx_gateway_ctx:authorize(Ctx, ClientInfo, subscribe, Topic) of
-                deny ->
-                    handle_out(error, {receipt_id(Headers), "Authorization Deny"}, Channel);
-                allow ->
-                    _ = emqx_broker:subscribe(MountedTopic),
-                    maybe_outgoing_receipt(
-                      receipt_id(Headers),
-                      Channel#channel{subscriptions = [{SubId, MountedTopic, Ack} | Subs]}
-                     )
-            end
+    case emqx_misc:pipeline(
+          [ fun parse_topic_filter/2
+          , fun check_subscribed_status/2
+          , fun check_sub_acl/2
+          ], {SubId, Topic}, Channel) of
+        {ok, {_, TopicFilter}, NChannel} ->
+            TopicFilters = [TopicFilter],
+            NTopicFilters = run_hooks(Ctx, 'client.subscribe',
+                                      [ClientInfo, #{}], TopicFilters),
+            case do_subscribe(NTopicFilters, NChannel) of
+                [] ->
+                    ErrMsg = "Permission denied",
+                    handle_out(error, {receipt_id(Headers), ErrMsg}, Channel);
+                [MountedTopic|_] ->
+                    NChannel1 = NChannel#channel{
+                                  subscriptions = [{SubId, MountedTopic, Ack}
+                                                   | Subs]
+                                 },
+                    handle_out(receipt, receipt_id(Headers), NChannel1)
+            end;
+        {error, ErrMsg, NChannel} ->
+            ?LOG(error, "Failed to subscribe topic ~s, reason: ~s",
+                        [Topic, ErrMsg]),
+            handle_out(error, {receipt_id(Headers), ErrMsg}, NChannel)
     end;
 
 handle_in(?PACKET(?CMD_UNSUBSCRIBE, Headers),
@@ -521,6 +523,54 @@ trans_pipeline([{Func, Args}|More], Outgoings, Channel) ->
             {error, Reason, Channel}
     end.
 
+%%--------------------------------------------------------------------
+%% Subs
+
+parse_topic_filter({SubId, Topic}, Channel) ->
+    TopicFilter = emqx_topic:parse(Topic),
+    {ok, {SubId, TopicFilter}, Channel}.
+
+check_subscribed_status({SubId, TopicFilter},
+                        #channel{
+                           subscriptions = Subs,
+                           clientinfo = #{mountpoint := Mountpoint}
+                          }) ->
+    MountedTopic = emqx_mountpoint:mount(Mountpoint, TopicFilter),
+    case lists:keyfind(SubId, 1, Subs) of
+        {SubId, MountedTopic, _Ack} ->
+            ok;
+        {SubId, _OtherTopic, _Ack} ->
+            {error, "Conflict subscribe id"};
+        false ->
+            ok
+    end.
+
+check_sub_acl({_SubId, TopicFilter},
+              #channel{
+                 ctx = Ctx,
+                 clientinfo = ClientInfo}) ->
+    case emqx_gateway_ctx:authorize(Ctx, ClientInfo, subscribe, TopicFilter) of
+        deny -> {error, "ACL Deny"};
+        allow -> ok
+    end.
+
+do_subscribe(TopicFilters, Channel) ->
+    do_subscribe(TopicFilters, Channel, []).
+
+do_subscribe([], _Channel, Acc) ->
+    lists:reverse(Acc);
+do_subscribe([{TopicFilter, Option}|More],
+             Channel = #channel{
+                          ctx = Ctx,
+                          clientinfo = ClientInfo
+                                     = #{clientid := ClientId,
+                                         mountpoint := Mountpoint}}, Acc) ->
+    SubOpts = maps:merge(emqx_gateway_utils:default_subopts(), Option),
+    MountedTopic = emqx_mountpoint:mount(Mountpoint, TopicFilter),
+    _ = emqx_broker:subscribe(MountedTopic, ClientId, SubOpts),
+    run_hooks(Ctx, 'session.subscribed', [ClientInfo, MountedTopic, SubOpts]),
+    do_subscribe(More, Channel, [MountedTopic|Acc]).
+
 %%--------------------------------------------------------------------
 %% Handle outgoing packet
 %%--------------------------------------------------------------------