%%%----------------------------------------------------------------------
%%% File : mod_push_keepalive.erl
%%% Author : Holger Weiss <holger@zedat.fu-berlin.de>
%%% Purpose : Keep pending XEP-0198 sessions alive with XEP-0357
%%% Created : 15 Jul 2017 by Holger Weiss <holger@zedat.fu-berlin.de>
%%%
%%%
%%% ejabberd, Copyright (C) 2017-2022 ProcessOne
%%%
%%% This program is free software; you can redistribute it and/or
%%% modify it under the terms of the GNU General Public License as
%%% published by the Free Software Foundation; either version 2 of the
%%% License, or (at your option) any later version.
%%%
%%% This program is distributed in the hope that it will be useful,
%%% but WITHOUT ANY WARRANTY; without even the implied warranty of
%%% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
%%% General Public License for more details.
%%%
%%% You should have received a copy of the GNU General Public License along
%%% with this program; if not, write to the Free Software Foundation, Inc.,
%%% 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
%%%
%%%----------------------------------------------------------------------
-module(mod_push_keepalive).
-author('holger@zedat.fu-berlin.de').
-behaviour(gen_mod).
%% gen_mod callbacks.
-export([start/2, stop/1, reload/3, mod_opt_type/1, mod_options/1, depends/2]).
-export([mod_doc/0]).
%% ejabberd_hooks callbacks.
-export([c2s_session_pending/1, c2s_session_resumed/1, c2s_copy_session/2,
c2s_handle_cast/2, c2s_handle_info/2, c2s_stanza/3]).
-include("logger.hrl").
-include_lib("xmpp/include/xmpp.hrl").
-include("translate.hrl").
-define(PUSH_BEFORE_TIMEOUT_PERIOD, 120000). % 2 minutes.
-type c2s_state() :: ejabberd_c2s:state().
%%--------------------------------------------------------------------
%% gen_mod callbacks.
%%--------------------------------------------------------------------
-spec start(binary(), gen_mod:opts()) -> ok.
start(Host, Opts) ->
case mod_push_keepalive_opt:wake_on_start(Opts) of
true ->
wake_all(Host);
false ->
ok
end,
register_hooks(Host).
-spec stop(binary()) -> ok.
stop(Host) ->
unregister_hooks(Host).
-spec reload(binary(), gen_mod:opts(), gen_mod:opts()) -> ok.
reload(Host, NewOpts, OldOpts) ->
case {mod_push_keepalive_opt:wake_on_start(NewOpts),
mod_push_keepalive_opt:wake_on_start(OldOpts)} of
{true, false} ->
wake_all(Host);
_ ->
ok
end.
-spec depends(binary(), gen_mod:opts()) -> [{module(), hard | soft}].
depends(_Host, _Opts) ->
[{mod_push, hard},
{mod_client_state, soft},
{mod_stream_mgmt, soft}].
-spec mod_opt_type(atom()) -> econf:validator().
mod_opt_type(resume_timeout) ->
econf:either(
econf:int(0, 0),
econf:timeout(second));
mod_opt_type(wake_on_start) ->
econf:bool();
mod_opt_type(wake_on_timeout) ->
econf:bool().
mod_options(_Host) ->
[{resume_timeout, timer:hours(72)},
{wake_on_start, false},
{wake_on_timeout, true}].
mod_doc() ->
#{desc =>
[?T("This module tries to keep the stream management "
"session (see _`mod_stream_mgmt`_) of a disconnected "
"mobile client alive if the client enabled push "
"notifications for that session. However, the normal "
"session resumption timeout is restored once a push "
"notification is issued, so the session will be closed "
"if the client doesn't respond to push notifications."), "",
?T("The module depends on _`mod_push`_.")],
opts =>
[{resume_timeout,
#{value => "timeout()",
desc =>
?T("This option specifies the period of time until "
"the session of a disconnected push client times out. "
"This timeout is only in effect as long as no push "
"notification is issued. Once that happened, the "
"resumption timeout configured for _`mod_stream_mgmt`_ "
"is restored. "
"The default value is '72' hours.")}},
{wake_on_start,
#{value => "true | false",
desc =>
?T("If this option is set to 'true', notifications "
"are generated for **all** registered push clients "
"during server startup. This option should not be "
"enabled on servers with many push clients as it "
"can generate significant load on the involved push "
"services and the server itself. "
"The default value is 'false'.")}},
{wake_on_timeout,
#{value => "true | false",
desc =>
?T("If this option is set to 'true', a notification "
"is generated shortly before the session would time "
"out as per the 'resume_timeout' option. "
"The default value is 'true'.")}}]}.
%%--------------------------------------------------------------------
%% Register/unregister hooks.
%%--------------------------------------------------------------------
-spec register_hooks(binary()) -> ok.
register_hooks(Host) ->
ejabberd_hooks:add(c2s_session_pending, Host, ?MODULE,
c2s_session_pending, 50),
ejabberd_hooks:add(c2s_session_resumed, Host, ?MODULE,
c2s_session_resumed, 50),
ejabberd_hooks:add(c2s_copy_session, Host, ?MODULE,
c2s_copy_session, 50),
ejabberd_hooks:add(c2s_handle_cast, Host, ?MODULE,
c2s_handle_cast, 40),
ejabberd_hooks:add(c2s_handle_info, Host, ?MODULE,
c2s_handle_info, 50),
ejabberd_hooks:add(c2s_handle_send, Host, ?MODULE,
c2s_stanza, 50).
-spec unregister_hooks(binary()) -> ok.
unregister_hooks(Host) ->
ejabberd_hooks:delete(c2s_session_pending, Host, ?MODULE,
c2s_session_pending, 50),
ejabberd_hooks:delete(c2s_session_resumed, Host, ?MODULE,
c2s_session_resumed, 50),
ejabberd_hooks:delete(c2s_copy_session, Host, ?MODULE,
c2s_copy_session, 50),
ejabberd_hooks:delete(c2s_handle_cast, Host, ?MODULE,
c2s_handle_cast, 40),
ejabberd_hooks:delete(c2s_handle_info, Host, ?MODULE,
c2s_handle_info, 50),
ejabberd_hooks:delete(c2s_handle_send, Host, ?MODULE,
c2s_stanza, 50).
%%--------------------------------------------------------------------
%% Hook callbacks.
%%--------------------------------------------------------------------
-spec c2s_stanza(c2s_state(), xmpp_element() | xmlel(), term()) -> c2s_state().
c2s_stanza(#{push_enabled := true, mgmt_state := pending} = State,
Pkt, _SendResult) ->
case mod_push:is_incoming_chat_msg(Pkt) of
true ->
maybe_restore_resume_timeout(State);
false ->
State
end;
c2s_stanza(State, _Pkt, _SendResult) ->
State.
-spec c2s_session_pending(c2s_state()) -> c2s_state().
c2s_session_pending(#{push_enabled := true, mgmt_queue := Queue} = State) ->
case mod_stream_mgmt:queue_find(fun mod_push:is_incoming_chat_msg/1,
Queue) of
none ->
State1 = maybe_adjust_resume_timeout(State),
maybe_start_wakeup_timer(State1);
_Msg ->
State
end;
c2s_session_pending(State) ->
State.
-spec c2s_session_resumed(c2s_state()) -> c2s_state().
c2s_session_resumed(#{push_enabled := true} = State) ->
maybe_restore_resume_timeout(State);
c2s_session_resumed(State) ->
State.
-spec c2s_copy_session(c2s_state(), c2s_state()) -> c2s_state().
c2s_copy_session(State, #{push_enabled := true,
push_resume_timeout := ResumeTimeout,
push_wake_on_timeout := WakeOnTimeout} = OldState) ->
State1 = case maps:find(push_resume_timeout_orig, OldState) of
{ok, Val} ->
State#{push_resume_timeout_orig => Val};
error ->
State
end,
State1#{push_resume_timeout => ResumeTimeout,
push_wake_on_timeout => WakeOnTimeout};
c2s_copy_session(State, _) ->
State.
-spec c2s_handle_cast(c2s_state(), any()) -> c2s_state().
c2s_handle_cast(#{lserver := LServer} = State, {push_enable, _ID}) ->
ResumeTimeout = mod_push_keepalive_opt:resume_timeout(LServer),
WakeOnTimeout = mod_push_keepalive_opt:wake_on_timeout(LServer),
State#{push_resume_timeout => ResumeTimeout,
push_wake_on_timeout => WakeOnTimeout};
c2s_handle_cast(State, push_disable) ->
State1 = maps:remove(push_resume_timeout, State),
maps:remove(push_wake_on_timeout, State1);
c2s_handle_cast(State, _Msg) ->
State.
-spec c2s_handle_info(c2s_state(), any()) -> c2s_state() | {stop, c2s_state()}.
c2s_handle_info(#{push_enabled := true, mgmt_state := pending,
jid := JID} = State, {timeout, _, push_keepalive}) ->
?INFO_MSG("Waking ~ts before session times out", [jid:encode(JID)]),
mod_push:notify(State, none, undefined),
{stop, State};
c2s_handle_info(State, _) ->
State.
%%--------------------------------------------------------------------
%% Internal functions.
%%--------------------------------------------------------------------
-spec maybe_adjust_resume_timeout(c2s_state()) -> c2s_state().
maybe_adjust_resume_timeout(#{push_resume_timeout := undefined} = State) ->
State;
maybe_adjust_resume_timeout(#{push_resume_timeout := Timeout} = State) ->
OrigTimeout = mod_stream_mgmt:get_resume_timeout(State),
?DEBUG("Adjusting resume timeout to ~B seconds", [Timeout div 1000]),
State1 = mod_stream_mgmt:set_resume_timeout(State, Timeout),
State1#{push_resume_timeout_orig => OrigTimeout}.
-spec maybe_restore_resume_timeout(c2s_state()) -> c2s_state().
maybe_restore_resume_timeout(#{push_resume_timeout_orig := Timeout} = State) ->
?DEBUG("Restoring resume timeout to ~B seconds", [Timeout div 1000]),
State1 = mod_stream_mgmt:set_resume_timeout(State, Timeout),
maps:remove(push_resume_timeout_orig, State1);
maybe_restore_resume_timeout(State) ->
State.
-spec maybe_start_wakeup_timer(c2s_state()) -> c2s_state().
maybe_start_wakeup_timer(#{push_wake_on_timeout := true,
push_resume_timeout := ResumeTimeout} = State)
when is_integer(ResumeTimeout), ResumeTimeout > ?PUSH_BEFORE_TIMEOUT_PERIOD ->
WakeTimeout = ResumeTimeout - ?PUSH_BEFORE_TIMEOUT_PERIOD,
?DEBUG("Scheduling wake-up timer to fire in ~B seconds", [WakeTimeout div 1000]),
erlang:start_timer(WakeTimeout, self(), push_keepalive),
State;
maybe_start_wakeup_timer(State) ->
State.
-spec wake_all(binary()) -> ok.
wake_all(LServer) ->
?INFO_MSG("Waking all push clients on ~ts", [LServer]),
Mod = gen_mod:db_mod(LServer, mod_push),
case Mod:lookup_sessions(LServer) of
{ok, Sessions} ->
IgnoreResponse = fun(_) -> ok end,
lists:foreach(fun({_, PushLJID, Node, XData}) ->
mod_push:notify(LServer, PushLJID, Node,
XData, none, undefined,
IgnoreResponse)
end, Sessions);
error ->
ok
end.
