%%%----------------------------------------------------------------------
%%% File : mod_vcard_xupdate.erl
%%% Author : Igor Goryachev <igor@goryachev.org>
%%% Purpose : Add avatar hash in presence on behalf of client (XEP-0153)
%%% Created : 9 Mar 2007 by Igor Goryachev <igor@goryachev.org>
%%%
%%%
%%% ejabberd, Copyright (C) 2002-2022 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_vcard_xupdate).
-behaviour(gen_mod).
-protocol({xep, 398, '0.2.0'}).
%% gen_mod callbacks
-export([start/2, stop/1, reload/3]).
-export([update_presence/1, vcard_set/1, remove_user/2, mod_doc/0,
user_send_packet/1, mod_opt_type/1, mod_options/1, depends/2]).
%% API
-export([compute_hash/1]).
-include("logger.hrl").
-include_lib("xmpp/include/xmpp.hrl").
-include("translate.hrl").
-define(VCARD_XUPDATE_CACHE, vcard_xupdate_cache).
%%====================================================================
%% gen_mod callbacks
%%====================================================================
start(Host, Opts) ->
init_cache(Host, Opts),
ejabberd_hooks:add(c2s_self_presence, Host, ?MODULE,
update_presence, 100),
ejabberd_hooks:add(user_send_packet, Host, ?MODULE,
user_send_packet, 50),
ejabberd_hooks:add(vcard_iq_set, Host, ?MODULE, vcard_set,
90),
ejabberd_hooks:add(remove_user, Host, ?MODULE, remove_user, 50).
stop(Host) ->
ejabberd_hooks:delete(c2s_self_presence, Host,
?MODULE, update_presence, 100),
ejabberd_hooks:delete(user_send_packet, Host, ?MODULE,
user_send_packet, 50),
ejabberd_hooks:delete(vcard_iq_set, Host, ?MODULE,
vcard_set, 90),
ejabberd_hooks:delete(remove_user, Host, ?MODULE, remove_user, 50).
reload(Host, NewOpts, _OldOpts) ->
init_cache(Host, NewOpts).
depends(_Host, _Opts) ->
[{mod_vcard, hard}].
%%====================================================================
%% Hooks
%%====================================================================
-spec update_presence({presence(), ejabberd_c2s:state()})
-> {presence(), ejabberd_c2s:state()}.
update_presence({#presence{type = available} = Pres,
#{jid := #jid{luser = LUser, lserver = LServer}} = State}) ->
case xmpp:get_subtag(Pres, #vcard_xupdate{}) of
#vcard_xupdate{hash = <<>>} ->
%% XEP-0398 forbids overwriting vcard:x:update
%% tags with empty <photo/> element
{Pres, State};
_ ->
Pres1 = case get_xupdate(LUser, LServer) of
undefined -> xmpp:remove_subtag(Pres, #vcard_xupdate{});
XUpdate -> xmpp:set_subtag(Pres, XUpdate)
end,
{Pres1, State}
end;
update_presence(Acc) ->
Acc.
-spec user_send_packet({presence(), ejabberd_c2s:state()})
-> {presence(), ejabberd_c2s:state()}.
user_send_packet({#presence{type = available,
to = #jid{luser = U, lserver = S,
lresource = <<"">>}},
#{jid := #jid{luser = U, lserver = S}}} = Acc) ->
%% This is processed by update_presence/2 explicitly, we don't
%% want to call this multiple times for performance reasons
Acc;
user_send_packet(Acc) ->
update_presence(Acc).
-spec vcard_set(iq()) -> iq().
vcard_set(#iq{from = #jid{luser = LUser, lserver = LServer}} = IQ) ->
ets_cache:delete(?VCARD_XUPDATE_CACHE, {LUser, LServer}),
ejabberd_sm:force_update_presence({LUser, LServer}),
IQ;
vcard_set(Acc) ->
Acc.
-spec remove_user(binary(), binary()) -> ok.
remove_user(User, Server) ->
LUser = jid:nodeprep(User),
LServer = jid:nameprep(Server),
ets_cache:delete(?VCARD_XUPDATE_CACHE, {LUser, LServer}).
%%====================================================================
%% Storage
%%====================================================================
-spec get_xupdate(binary(), binary()) -> vcard_xupdate() | undefined.
get_xupdate(LUser, LServer) ->
Result = case use_cache(LServer) of
true ->
ets_cache:lookup(
?VCARD_XUPDATE_CACHE, {LUser, LServer},
fun() -> db_get_xupdate(LUser, LServer) end);
false ->
db_get_xupdate(LUser, LServer)
end,
case Result of
{ok, external} -> undefined;
{ok, Hash} -> #vcard_xupdate{hash = Hash};
error -> #vcard_xupdate{}
end.
-spec db_get_xupdate(binary(), binary()) -> {ok, binary() | external} | error.
db_get_xupdate(LUser, LServer) ->
case mod_vcard:get_vcard(LUser, LServer) of
[VCard] ->
{ok, compute_hash(VCard)};
_ ->
error
end.
-spec init_cache(binary(), gen_mod:opts()) -> ok.
init_cache(Host, Opts) ->
case use_cache(Host) of
true ->
CacheOpts = cache_opts(Opts),
ets_cache:new(?VCARD_XUPDATE_CACHE, CacheOpts);
false ->
ets_cache:delete(?VCARD_XUPDATE_CACHE)
end.
-spec cache_opts(gen_mod:opts()) -> [proplists:property()].
cache_opts(Opts) ->
MaxSize = mod_vcard_xupdate_opt:cache_size(Opts),
CacheMissed = mod_vcard_xupdate_opt:cache_missed(Opts),
LifeTime = mod_vcard_xupdate_opt:cache_life_time(Opts),
[{max_size, MaxSize}, {cache_missed, CacheMissed}, {life_time, LifeTime}].
-spec use_cache(binary()) -> boolean().
use_cache(Host) ->
mod_vcard_xupdate_opt:use_cache(Host).
-spec compute_hash(xmlel()) -> binary() | external.
compute_hash(VCard) ->
case fxml:get_subtag(VCard, <<"PHOTO">>) of
false ->
<<>>;
Photo ->
try xmpp:decode(Photo, ?NS_VCARD, []) of
#vcard_photo{binval = <<_, _/binary>> = BinVal} ->
str:sha(BinVal);
#vcard_photo{extval = <<_, _/binary>>} ->
external;
_ ->
<<>>
catch _:{xmpp_codec, _} ->
<<>>
end
end.
%%====================================================================
%% Options
%%====================================================================
mod_opt_type(use_cache) ->
econf:bool();
mod_opt_type(cache_size) ->
econf:pos_int(infinity);
mod_opt_type(cache_missed) ->
econf:bool();
mod_opt_type(cache_life_time) ->
econf:timeout(second, infinity).
mod_options(Host) ->
[{use_cache, ejabberd_option:use_cache(Host)},
{cache_size, ejabberd_option:cache_size(Host)},
{cache_missed, ejabberd_option:cache_missed(Host)},
{cache_life_time, ejabberd_option:cache_life_time(Host)}].
mod_doc() ->
#{desc =>
[?T("The user's client can store an avatar in the "
"user vCard. The vCard-Based Avatars protocol "
"(https://xmpp.org/extensions/xep-0153.html[XEP-0153]) "
"provides a method for clients to inform the contacts "
"what is the avatar hash value. However, simple or small "
"clients may not implement that protocol."), "",
?T("If this module is enabled, all the outgoing client presence "
"stanzas get automatically the avatar hash on behalf of the "
"client. So, the contacts receive the presence stanzas with "
"the 'Update Data' described in "
"https://xmpp.org/extensions/xep-0153.html[XEP-0153] as if the "
"client would had inserted it itself. If the client had already "
"included such element in the presence stanza, it is replaced "
"with the element generated by ejabberd."), "",
?T("By enabling this module, each vCard modification produces "
"a hash recalculation, and each presence sent by a client "
"produces hash retrieval and a presence stanza rewrite. "
"For this reason, enabling this module will introduce a "
"computational overhead in servers with clients that change "
"frequently their presence. However, the overhead is significantly "
"reduced by the use of caching, so you probably don't want "
"to set 'use_cache' to 'false'."), "",
?T("The module depends on _`mod_vcard`_."), "",
?T("NOTE: Nowadays https://xmpp.org/extensions/xep-0153.html"
"[XEP-0153] is used mostly as \"read-only\", i.e. modern "
"clients don't publish their avatars inside vCards. Thus "
"in the majority of cases the module is only used along "
"with _`mod_avatar`_ for providing backward compatibility.")],
opts =>
[{use_cache,
#{value => "true | false",
desc =>
?T("Same as top-level _`use_cache`_ option, but applied to this module only.")}},
{cache_size,
#{value => "pos_integer() | infinity",
desc =>
?T("Same as top-level _`cache_size`_ option, but applied to this module only.")}},
{cache_missed,
#{value => "true | false",
desc =>
?T("Same as top-level _`cache_missed`_ option, but applied to this module only.")}},
{cache_life_time,
#{value => "timeout()",
desc =>
?T("Same as top-level _`cache_life_time`_ option, but applied to this module only.")}}]}.
