emqx/src/emqx_mountpoint.erl

80 lines
2.6 KiB
Erlang

%%--------------------------------------------------------------------
%% Copyright (c) 2018-2022 EMQ Technologies Co., Ltd. All Rights Reserved.
%%
%% Licensed under the Apache License, Version 2.0 (the "License");
%% you may not use this file except in compliance with the License.
%% You may obtain a copy of the License at
%%
%% http://www.apache.org/licenses/LICENSE-2.0
%%
%% Unless required by applicable law or agreed to in writing, software
%% distributed under the License is distributed on an "AS IS" BASIS,
%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
%% See the License for the specific language governing permissions and
%% limitations under the License.
%%--------------------------------------------------------------------
-module(emqx_mountpoint).
-include("emqx.hrl").
-include("types.hrl").
-export([ mount/2
, unmount/2
]).
-export([replvar/2]).
-export_type([mountpoint/0]).
-type(mountpoint() :: binary()).
-spec(mount(maybe(mountpoint()), Any) -> Any
when Any :: emqx_types:topic()
| emqx_types:message()
| emqx_types:topic_filters()).
mount(undefined, Any) ->
Any;
mount(MountPoint, Topic) when is_binary(Topic) ->
prefix(MountPoint, Topic);
mount(MountPoint, Msg = #message{topic = Topic}) ->
Msg#message{topic = prefix(MountPoint, Topic)};
mount(MountPoint, TopicFilters) when is_list(TopicFilters) ->
[{prefix(MountPoint, Topic), SubOpts} || {Topic, SubOpts} <- TopicFilters].
%% @private
-compile({inline, [prefix/2]}).
prefix(MountPoint, Topic) ->
<<MountPoint/binary, Topic/binary>>.
-spec(unmount(maybe(mountpoint()), Any) -> Any
when Any :: emqx_types:topic()
| emqx_types:message()).
unmount(undefined, Any) ->
Any;
unmount(MountPoint, Topic) when is_binary(Topic) ->
case string:prefix(Topic, MountPoint) of
nomatch -> Topic;
Topic1 -> Topic1
end;
unmount(MountPoint, Msg = #message{topic = Topic}) ->
case string:prefix(Topic, MountPoint) of
nomatch -> Msg;
Topic1 -> Msg#message{topic = Topic1}
end.
-spec(replvar(maybe(mountpoint()), map()) -> maybe(mountpoint())).
replvar(undefined, _Vars) ->
undefined;
replvar(MountPoint, #{clientid := ClientId, username := Username}) ->
lists:foldl(fun feed_var/2, MountPoint,
[{<<"%c">>, ClientId}, {<<"%u">>, Username}]).
feed_var({<<"%c">>, ClientId}, MountPoint) ->
emqx_topic:feed_var(<<"%c">>, ClientId, MountPoint);
feed_var({<<"%u">>, undefined}, MountPoint) ->
MountPoint;
feed_var({<<"%u">>, Username}, MountPoint) ->
emqx_topic:feed_var(<<"%u">>, Username, MountPoint).