emqx/src/emqx_mqtt_caps.erl

161 lines
5.5 KiB
Erlang

%%--------------------------------------------------------------------
%% Copyright (c) 2020 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.
%%--------------------------------------------------------------------
%% @doc MQTTv5 Capabilities
-module(emqx_mqtt_caps).
-include("emqx_mqtt.hrl").
-include("types.hrl").
-export([ check_pub/2
, check_sub/3
]).
-export([ get_caps/1
, get_caps/2
, get_caps/3
]).
-export([default_caps/0]).
-export([default/0]).
-export_type([caps/0]).
-type(caps() :: #{max_packet_size => integer(),
max_clientid_len => integer(),
max_topic_alias => integer(),
max_topic_levels => integer(),
max_qos_allowed => emqx_types:qos(),
retain_available => boolean(),
wildcard_subscription => boolean(),
subscription_identifiers => boolean(),
shared_subscription => boolean()
}).
-define(UNLIMITED, 0).
-define(PUBCAP_KEYS, [max_topic_levels,
max_qos_allowed,
retain_available
]).
-define(SUBCAP_KEYS, [max_topic_levels,
max_qos_allowed,
wildcard_subscription,
shared_subscription
]).
-define(DEFAULT_CAPS, #{max_packet_size => ?MAX_PACKET_SIZE,
max_clientid_len => ?MAX_CLIENTID_LEN,
max_topic_alias => ?MAX_TOPIC_AlIAS,
max_topic_levels => ?UNLIMITED,
max_qos_allowed => ?QOS_2,
retain_available => true,
wildcard_subscription => true,
subscription_identifiers => true,
shared_subscription => true
}).
-spec(check_pub(emqx_types:zone(),
#{qos := emqx_types:qos(),
retain := boolean(),
topic := emqx_topic:topic()})
-> ok_or_error(emqx_types:reason_code())).
check_pub(Zone, Flags) when is_map(Flags) ->
do_check_pub(case maps:take(topic, Flags) of
{Topic, Flags1} ->
Flags1#{topic_levels => emqx_topic:levels(Topic)};
error ->
Flags
end, get_caps(Zone, publish)).
do_check_pub(#{topic_levels := Levels}, #{max_topic_levels := Limit})
when Limit > 0, Levels > Limit ->
{error, ?RC_TOPIC_NAME_INVALID};
do_check_pub(#{qos := QoS}, #{max_qos_allowed := MaxQoS})
when QoS > MaxQoS ->
{error, ?RC_QOS_NOT_SUPPORTED};
do_check_pub(#{retain := true}, #{retain_available := false}) ->
{error, ?RC_RETAIN_NOT_SUPPORTED};
do_check_pub(_Flags, _Caps) -> ok.
-spec(check_sub(emqx_types:zone(),
emqx_types:topic(),
emqx_types:subopts())
-> ok_or_error(emqx_types:reason_code())).
check_sub(Zone, Topic, SubOpts) ->
Caps = get_caps(Zone, subscribe),
Flags = lists:foldl(
fun(max_topic_levels, Map) ->
Map#{topic_levels => emqx_topic:levels(Topic)};
(wildcard_subscription, Map) ->
Map#{is_wildcard => emqx_topic:wildcard(Topic)};
(shared_subscription, Map) ->
Map#{is_shared => maps:is_key(share, SubOpts)};
(_Key, Map) -> Map %% Ignore
end, #{}, maps:keys(Caps)),
do_check_sub(Flags, Caps).
do_check_sub(#{topic_levels := Levels}, #{max_topic_levels := Limit})
when Limit > 0, Levels > Limit ->
{error, ?RC_TOPIC_FILTER_INVALID};
do_check_sub(#{is_wildcard := true}, #{wildcard_subscription := false}) ->
{error, ?RC_WILDCARD_SUBSCRIPTIONS_NOT_SUPPORTED};
do_check_sub(#{is_shared := true}, #{shared_subscription := false}) ->
{error, ?RC_SHARED_SUBSCRIPTIONS_NOT_SUPPORTED};
do_check_sub(_Flags, _Caps) -> ok.
default_caps() ->
?DEFAULT_CAPS.
get_caps(Zone, Cap, Def) ->
emqx_zone:get_env(Zone, Cap, Def).
get_caps(Zone, publish) ->
with_env(Zone, '$mqtt_pub_caps',
fun() ->
filter_caps(?PUBCAP_KEYS, get_caps(Zone))
end);
get_caps(Zone, subscribe) ->
with_env(Zone, '$mqtt_sub_caps',
fun() ->
filter_caps(?SUBCAP_KEYS, get_caps(Zone))
end).
get_caps(Zone) ->
with_env(Zone, '$mqtt_caps',
fun() ->
maps:map(fun(Cap, Def) ->
emqx_zone:get_env(Zone, Cap, Def)
end, ?DEFAULT_CAPS)
end).
filter_caps(Keys, Caps) ->
maps:filter(fun(Key, _Val) -> lists:member(Key, Keys) end, Caps).
-spec(default() -> caps()).
default() -> ?DEFAULT_CAPS.
with_env(Zone, Key, InitFun) ->
case emqx_zone:get_env(Zone, Key) of
undefined -> Caps = InitFun(),
ok = emqx_zone:set_env(Zone, Key, Caps),
Caps;
ZoneCaps -> ZoneCaps
end.