96 lines
3.4 KiB
Erlang
96 lines
3.4 KiB
Erlang
%%--------------------------------------------------------------------
|
|
%% Copyright (c) 2017-2023 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_keepalive).
|
|
|
|
-export([ init/1
|
|
, info/1
|
|
, info/2
|
|
, check/2
|
|
, set/3
|
|
]).
|
|
|
|
-export_type([keepalive/0]).
|
|
-elvis([{elvis_style, no_if_expression, disable}]).
|
|
|
|
-record(keepalive, {
|
|
interval :: pos_integer(),
|
|
statval :: non_neg_integer(),
|
|
repeat :: non_neg_integer()
|
|
}).
|
|
|
|
-opaque(keepalive() :: #keepalive{}).
|
|
|
|
%% @doc Init keepalive.
|
|
-spec(init(Interval :: non_neg_integer()) -> keepalive()).
|
|
init(Interval) when Interval > 0 ->
|
|
#keepalive{interval = Interval,
|
|
statval = 0,
|
|
repeat = 0}.
|
|
|
|
%% @doc Get Info of the keepalive.
|
|
-spec(info(keepalive()) -> emqx_types:infos()).
|
|
info(#keepalive{interval = Interval,
|
|
statval = StatVal,
|
|
repeat = Repeat}) ->
|
|
#{interval => Interval,
|
|
statval => StatVal,
|
|
repeat => Repeat
|
|
}.
|
|
|
|
-spec(info(interval | statval | repeat, keepalive())
|
|
-> non_neg_integer()).
|
|
info(interval, #keepalive{interval = Interval}) ->
|
|
Interval;
|
|
info(statval, #keepalive{statval = StatVal}) ->
|
|
StatVal;
|
|
info(repeat, #keepalive{repeat = Repeat}) ->
|
|
Repeat.
|
|
|
|
%% @doc Check keepalive.
|
|
-spec(check(non_neg_integer(), keepalive())
|
|
-> {ok, keepalive()} | {error, timeout}).
|
|
check(NewVal, KeepAlive = #keepalive{statval = OldVal,
|
|
repeat = Repeat}) ->
|
|
if
|
|
NewVal =/= OldVal ->
|
|
{ok, KeepAlive#keepalive{statval = NewVal, repeat = 0}};
|
|
Repeat < 1 ->
|
|
{ok, KeepAlive#keepalive{repeat = Repeat + 1}};
|
|
true -> {error, timeout}
|
|
end.
|
|
|
|
-define(IS_KEEPALIVE(Interval), Interval >= 0 andalso Interval =< 65535000).
|
|
%% from mqtt-v3.1.1 specific
|
|
%% A Keep Alive value of zero (0) has the effect of turning off the keep alive mechanism.
|
|
%% This means that, in this case, the Server is not required
|
|
%% to disconnect the Client on the grounds of inactivity.
|
|
%% Note that a Server is permitted to disconnect a Client that it determines
|
|
%% to be inactive or non-responsive at any time,
|
|
%% regardless of the Keep Alive value provided by that Client.
|
|
%% Non normative comment
|
|
%%The actual value of the Keep Alive is application specific;
|
|
%% typically this is a few minutes.
|
|
%% The maximum value is (65535s) 18 hours 12 minutes and 15 seconds.
|
|
|
|
%% @doc Update keepalive interval
|
|
%% The keepalive() is undefined when connecting via keepalive=0.
|
|
-spec(set(interval, non_neg_integer(), keepalive() | undefined) -> keepalive()).
|
|
set(interval, Interval, undefined) when ?IS_KEEPALIVE(Interval) ->
|
|
init(Interval);
|
|
set(interval, Interval, KeepAlive) when ?IS_KEEPALIVE(Interval) ->
|
|
KeepAlive#keepalive{interval = Interval}.
|