mod_foo.erl

%%%-------------------------------------------------------------------
%%% @author xram <[email protected]>
%%% @copyright (C) 2018, xram
%%% @doc
%%%
%%% @end
%%% Created : 28 Mar 2018 by xram <[email protected]>
%%%-------------------------------------------------------------------
-module(mod_foo).
-behaviour(gen_mod).

%% API
-export([start/2, stop/1, reload/3, depends/2, mod_options/1]).
-export([roster_in_subscription/2]).

-include("xmpp.hrl").
-include("mod_roster.hrl").

%%%===================================================================
%%% API
%%%===================================================================
start(Host, _) ->
    ejabberd_hooks:add(roster_in_subscription, Host,
		       ?MODULE, roster_in_subscription, 30).

stop(Host) ->
    ejabberd_hooks:delete(roster_in_subscription, Host,
			  ?MODULE, roster_in_subscription, 30).

reload(_, _, _) ->
    ok.

depends(_, _) ->
    [{mod_roster, hard}].

mod_options(_) ->
    [].

roster_in_subscription(Acc, #presence{from = From, to = To,
				      type = subscribe} = Pres) ->
    case is_valid_token(Pres) of
	true ->
	    {LUser, LServer, _} = jid:tolower(To),
	    {Sub, _Ask, Groups} = ejabberd_hooks:run_fold(
				    roster_get_jid_info, LServer,
				    {none, none, []},
				    [LUser, LServer, From]),
	    case Sub of
		both ->
		    Acc;
		from ->
		    Acc;
		_ ->
		    {NewSub, NewAsk} = case Sub of
					   to -> {both, none};
					   none -> {from, out}
				       end,
		    LFrom = jid:tolower(jid:remove_resource(From)),
		    Item = #roster{us = {LUser, LServer},
				   usj = {LUser, LServer, LFrom},
				   jid = LFrom,
				   subscription = NewSub,
				   ask = NewAsk,
				   groups = Groups},
		    mod_roster:set_roster(Item),
		    mod_roster:push_item(To, Item#roster{subscription = none}, Item),
		    ejabberd_router:route(
		      #presence{from = To, to = From, type = subscribed}),
		    {stop, false}
	    end;
	false ->
	    Acc
    end;
roster_in_subscription(Acc, _) ->
    Acc.

%%%===================================================================
%%% Internal functions
%%%===================================================================
is_valid_token(#presence{from = From} = Pres) ->
    case xmpp:get_subtag(Pres, #preauth{}) of
	#preauth{token = Token} ->
	    case read_database(From, Token) of
		ok ->
		    true;
		_ ->
		    false
	    end;
	false ->
	    false
    end.

read_database(_, _) ->
    ok.