diff options
Diffstat (limited to 'src/mod_applepush_service.erl')
| -rw-r--r-- | src/mod_applepush_service.erl | 704 |
1 files changed, 704 insertions, 0 deletions
diff --git a/src/mod_applepush_service.erl b/src/mod_applepush_service.erl new file mode 100644 index 000000000..995447a0d --- /dev/null +++ b/src/mod_applepush_service.erl @@ -0,0 +1,704 @@ +%%%---------------------------------------------------------------------- +%%% File : mod_applepush_service.erl +%%% Author : Alexey Shchepin <alexey@process-one.net> +%%% Purpose : Central push infrastructure +%%% Created : 5 Jun 2009 by Alexey Shchepin <alexey@process-one.net> +%%% +%%% ejabberd, Copyright (C) 2002-2009 ProcessOne +%%%---------------------------------------------------------------------- + +-module(mod_applepush_service). +-author('alexey@process-one.net'). + +-behaviour(gen_server). +-behaviour(gen_mod). + +%% API +-export([start_link/2, start/2, stop/1]). + +%% gen_server callbacks +-export([init/1, handle_call/3, handle_cast/2, handle_info/2, + terminate/2, code_change/3]). + + +-include("ejabberd.hrl"). +-include("jlib.hrl"). +-include_lib("kernel/include/file.hrl"). + +-record(state, {host = <<"">> :: binary(), + socket :: ssl:sslsocket(), + gateway = "" :: string(), + port = 2195 :: inet:port_number(), + feedback_socket :: ssl:sslsocket(), + feedback :: string(), + feedback_port = 2196 :: inet:port_number(), + feedback_buf = <<>> :: binary(), + certfile = "" :: string(), + certfile_mtime :: file:date_time(), + failure_script :: string(), + queue = {0, queue:new()} :: {non_neg_integer(), queue()}, + soundfile = <<"">> :: binary(), + cmd_id = 0 :: non_neg_integer(), + cmd_cache = dict:new() :: dict(), + device_cache = dict:new() :: dict()}). + +-define(PROCNAME, ejabberd_mod_applepush_service). +-define(RECONNECT_TIMEOUT, 5000). +-define(FEEDBACK_RECONNECT_TIMEOUT, 30000). +-define(HANDSHAKE_TIMEOUT, 60000). +-define(SSL_TIMEOUT, 5000). +-define(MAX_QUEUE_SIZE, 1000). +-define(CACHE_SIZE, 4096). +-define(MAX_PAYLOAD_SIZE, 255). + +-define(NS_P1_PUSH, <<"p1:push">>). + +%%==================================================================== +%% API +%%==================================================================== +%%-------------------------------------------------------------------- +%% Function: start_link() -> {ok,Pid} | ignore | {error,Error} +%% Description: Starts the server +%%-------------------------------------------------------------------- +start_link(Host, Opts) -> + Proc = gen_mod:get_module_proc(Host, ?PROCNAME), + gen_server:start_link({local, Proc}, ?MODULE, [Host, Opts], []). + +start(Host, Opts) -> + ssl:start(), + MyHosts = case catch gen_mod:get_opt( + hosts, Opts, + fun(L) when is_list(L) -> + [{iolist_to_binary(H), O} || {H, O}<-L] + end, []) of + {'EXIT', _} -> + [{gen_mod:get_opt_host(Host, Opts, + <<"applepush.@HOST@">>), Opts}]; + Hs -> + Hs + end, + lists:foreach( + fun({MyHost, MyOpts}) -> + Proc = gen_mod:get_module_proc(MyHost, ?PROCNAME), + ChildSpec = + {Proc, + {?MODULE, start_link, [MyHost, MyOpts]}, + transient, + 1000, + worker, + [?MODULE]}, + supervisor:start_child(ejabberd_sup, ChildSpec) + end, MyHosts). + +stop(Host) -> + MyHosts = case gen_mod:get_module_opt( + Host, ?MODULE, hosts, + fun(Hs) when is_list(Hs) -> + [iolist_to_binary(H) || {H, _} <- Hs] + end, []) of + [] -> + [gen_mod:get_module_opt_host( + Host, ?MODULE, <<"applepush.@HOST@">>)]; + Hs -> + Hs + end, + lists:foreach( + fun(MyHost) -> + Proc = gen_mod:get_module_proc(MyHost, ?PROCNAME), + gen_server:call(Proc, stop), + supervisor:terminate_child(ejabberd_sup, Proc), + supervisor:delete_child(ejabberd_sup, Proc) + end, MyHosts). + + +%%==================================================================== +%% gen_server callbacks +%%==================================================================== + +%%-------------------------------------------------------------------- +%% Function: init(Args) -> {ok, State} | +%% {ok, State, Timeout} | +%% ignore | +%% {stop, Reason} +%% Description: Initiates the server +%%-------------------------------------------------------------------- +init([MyHost, Opts]) -> + CertFile = gen_mod:get_opt(certfile, Opts, + fun iolist_to_string/1, + ""), + SoundFile = gen_mod:get_opt(sound_file, Opts, + fun iolist_to_binary/1, + <<"pushalert.wav">>), + Gateway = gen_mod:get_opt(gateway, Opts, + fun iolist_to_string/1, + "gateway.push.apple.com"), + Feedback = gen_mod:get_opt(feedback, Opts, + fun iolist_to_string/1, + undefined), + Port = gen_mod:get_opt(port, Opts, + fun(I) when is_integer(I), I>0, I<65536 -> I end, + 2195), + FeedbackPort = gen_mod:get_opt(feedback_port, Opts, + fun(I) when is_integer(I), I>0, I<65536 -> I end, + 2196), + FailureScript = gen_mod:get_opt(failure_script, Opts, + fun iolist_to_string/1, + undefined), + self() ! connect, + case Feedback of + undefined -> + ok; + _ -> + self() ! connect_feedback + end, + ejabberd_router:register_route(MyHost), + {ok, #state{host = MyHost, + gateway = Gateway, + port = Port, + feedback = Feedback, + feedback_port = FeedbackPort, + certfile = CertFile, + failure_script = FailureScript, + queue = {0, queue:new()}, + soundfile = SoundFile}}. + +%%-------------------------------------------------------------------- +%% Function: %% handle_call(Request, From, State) -> {reply, Reply, State} | +%% {reply, Reply, State, Timeout} | +%% {noreply, State} | +%% {noreply, State, Timeout} | +%% {stop, Reason, Reply, State} | +%% {stop, Reason, State} +%% Description: Handling call messages +%%-------------------------------------------------------------------- +handle_call(stop, _From, State) -> + {stop, normal, ok, State}. + +%%-------------------------------------------------------------------- +%% Function: handle_cast(Msg, State) -> {noreply, State} | +%% {noreply, State, Timeout} | +%% {stop, Reason, State} +%% Description: Handling cast messages +%%-------------------------------------------------------------------- +handle_cast(_Msg, State) -> + {noreply, State}. + +%%-------------------------------------------------------------------- +%% Function: handle_info(Info, State) -> {noreply, State} | +%% {noreply, State, Timeout} | +%% {stop, Reason, State} +%% Description: Handling all non call/cast messages +%%-------------------------------------------------------------------- +handle_info({route, From, To, Packet}, State) -> + case catch do_route(From, To, Packet, State) of + {'EXIT', Reason} -> + ?ERROR_MSG("~p", [Reason]), + {noreply, State}; + Res -> + Res + end; +handle_info(connect, State) -> + connect(State); +handle_info(connect_feedback, #state{certfile_mtime = MTime} = State) + when MTime /= undefined -> + erlang:send_after(?FEEDBACK_RECONNECT_TIMEOUT, self(), + connect_feedback), + {noreply, State}; +handle_info(connect_feedback, State) + when State#state.feedback /= undefined, + State#state.feedback_socket == undefined -> + Feedback = State#state.feedback, + FeedbackPort = State#state.feedback_port, + CertFile = State#state.certfile, + case ssl:connect(Feedback, FeedbackPort, + [{certfile, CertFile}, + {active, true}, + binary], ?SSL_TIMEOUT) of + {ok, Socket} -> + ?INFO_MSG("(~p) Connected to ~p:~p", + [State#state.host, Feedback, FeedbackPort]), + {noreply, State#state{feedback_socket = Socket}}; + {error, Reason} -> + ?ERROR_MSG("(~p) Connection to ~p:~p failed: ~p, " + "retrying after ~p seconds", + [State#state.host, Feedback, FeedbackPort, + Reason, ?FEEDBACK_RECONNECT_TIMEOUT div 1000]), + erlang:send_after(?FEEDBACK_RECONNECT_TIMEOUT, self(), + connect_feedback), + {noreply, State} + end; +handle_info({ssl, Socket, Packet}, State) + when Socket == State#state.socket -> + case Packet of + <<8, Status, CmdID:32>> when Status /= 0 -> + case dict:find(CmdID, State#state.cmd_cache) of + {ok, {JID, _DeviceID}} -> + ?ERROR_MSG("PUSH ERROR for ~p: ~p", [JID, Status]), + if + Status == 8 -> + From = jlib:make_jid(<<"">>, State#state.host, <<"">>), + ejabberd_router:route( + From, JID, + #xmlel{name = <<"message">>, attrs = [], + children = + [#xmlel{name = <<"disable">>, + attrs = [{<<"xmlns">>, ?NS_P1_PUSH}, + {<<"status">>, + jlib:integer_to_binary(Status)}], + children = []}]}); + true -> + ok + end, + ok; + error -> + ?ERROR_MSG("Unknown cmd ID ~p~n", [CmdID]), + ok + end; + _ -> + ?ERROR_MSG("Received unknown packet ~p~n", [Packet]) + end, + {noreply, State}; +handle_info({ssl, Socket, Packet}, State) + when Socket == State#state.feedback_socket -> + ?INFO_MSG("(~p) feedback: ~p", [State#state.host, Packet]), + Buf = <<(State#state.feedback_buf)/binary, Packet/binary>>, + Buf2 = parse_feedback_buf(Buf, State), + {noreply, State#state{feedback_buf = Buf2}}; +handle_info({ssl_closed, Socket}, State) + when Socket == State#state.feedback_socket -> + ssl:close(Socket), + erlang:send_after(?FEEDBACK_RECONNECT_TIMEOUT, self(), + connect_feedback), + {noreply, State#state{feedback_socket = undefined, + feedback_buf = <<>>}}; +handle_info(_Info, State) -> + %io:format("got info: ~p~n", [_Info]), + {noreply, State}. + +%%-------------------------------------------------------------------- +%% Function: terminate(Reason, State) -> void() +%% Description: This function is called by a gen_server when it is about to +%% terminate. It should be the opposite of Module:init/1 and do any necessary +%% cleaning up. When it returns, the gen_server terminates with Reason. +%% The return value is ignored. +%%-------------------------------------------------------------------- +terminate(_Reason, State) -> + ejabberd_router:unregister_route(State#state.host), + ok. + +%%-------------------------------------------------------------------- +%% Func: code_change(OldVsn, State, Extra) -> {ok, NewState} +%% Description: Convert process state when code is changed +%%-------------------------------------------------------------------- +code_change(_OldVsn, State, _Extra) -> + {ok, State}. + +%%%---------------------------------------------------------------------- +%%% Internal functions +%%%---------------------------------------------------------------------- + +do_route(From, To, Packet, State) -> + #jid{user = User, resource = Resource} = To, + if + (User /= <<"">>) or (Resource /= <<"">>) -> + Err = jlib:make_error_reply(Packet, ?ERR_SERVICE_UNAVAILABLE), + ejabberd_router:route(To, From, Err), + {noreply, State}; + true -> + case Packet of + #xmlel{name = <<"iq">>} -> + IQ = jlib:iq_query_info(Packet), + case IQ of + #iq{type = get, xmlns = ?NS_DISCO_INFO = XMLNS, + sub_el = _SubEl, lang = Lang} = IQ -> + Res = IQ#iq{type = result, + sub_el = + [#xmlel{name = <<"query">>, + attrs = [{<<"xmlns">>, XMLNS}], + children = iq_disco(Lang)}]}, + ejabberd_router:route(To, + From, + jlib:iq_to_xml(Res)), + {noreply, State}; + #iq{type = get, xmlns = ?NS_DISCO_ITEMS = XMLNS} = IQ -> + Res = IQ#iq{type = result, + sub_el = + [#xmlel{name = <<"query">>, + attrs = [{<<"xmlns">>, XMLNS}], + children = []}]}, + ejabberd_router:route(To, + From, + jlib:iq_to_xml(Res)), + {noreply, State}; + _ -> + Err = jlib:make_error_reply(Packet, + ?ERR_SERVICE_UNAVAILABLE), + ejabberd_router:route(To, From, Err), + {noreply, State} + end; + #xmlel{name = <<"message">>, children = Els} -> + case xml:remove_cdata(Els) of + [#xmlel{name = <<"push">>}] -> + NewState = handle_message(From, To, Packet, State), + {noreply, NewState}; + [#xmlel{name = <<"disable">>}] -> + {noreply, State}; + _ -> + {noreply, State} + end; + _ -> + {noreply, State} + end + end. + +get_custom_fields(Packet) -> + case xml:get_subtag(xml:get_subtag(Packet, <<"push">>), <<"custom">>) of + false -> []; + #xmlel{name = <<"custom">>, attrs = [], children = Children} -> + [ {xml:get_tag_attr_s(<<"name">>, C), xml:get_tag_cdata(C)} || + C <- xml:remove_cdata(Children) ] + end. + +handle_message(From, To, Packet, #state{socket = undefined} = State) -> + queue_message(From, To, Packet, State); +handle_message(From, To, Packet, State) -> + DeviceID = + xml:get_path_s(Packet, + [{elem, <<"push">>}, {elem, <<"id">>}, cdata]), + Msg = + xml:get_path_s(Packet, + [{elem, <<"push">>}, {elem, <<"msg">>}, cdata]), + Badge = + xml:get_path_s(Packet, + [{elem, <<"push">>}, {elem, <<"badge">>}, cdata]), + Sound = + xml:get_path_s(Packet, + [{elem, <<"push">>}, {elem, <<"sound">>}, cdata]), + Sender = + xml:get_path_s(Packet, + [{elem, <<"push">>}, {elem, <<"from">>}, cdata]), + Receiver = + xml:get_path_s(Packet, + [{elem, <<"push">>}, {elem, <<"to">>}, cdata]), + CustomFields = get_custom_fields(Packet), + Payload = make_payload(State, Msg, Badge, Sound, Sender, CustomFields), + ID = + case catch erlang:list_to_integer(binary_to_list(DeviceID), 16) of + ID1 when is_integer(ID1) -> + ID1; + _ -> + false + end, + if + is_integer(ID) -> + Command = 1, + CmdID = State#state.cmd_id, + {MegaSecs, Secs, _MicroSecs} = now(), + Expiry = MegaSecs * 1000000 + Secs + 24 * 60 * 60, + BDeviceID = <<ID:256>>, + IDLen = size(BDeviceID), + PayloadLen = size(Payload), + Notification = + <<Command:8, + CmdID:32, + Expiry:32, + IDLen:16, + BDeviceID/binary, + PayloadLen:16, + Payload/binary>>, + ?INFO_MSG("(~p) sending notification for ~s~n~p~npayload:~n~s~n" + "Sender: ~s~n" + "Receiver: ~s~n" + "Device ID: ~s~n", + [State#state.host, erlang:integer_to_list(ID, 16), + Notification, Payload, + Sender, + Receiver, DeviceID]), + case ssl:send(State#state.socket, Notification) of + ok -> + cache(From, ID, State); + {error, Reason} -> + ?INFO_MSG("(~p) Connection closed: ~p, reconnecting", + [State#state.host, Reason]), + ssl:close(State#state.socket), + self() ! connect, + queue_message(From, To, Packet, + State#state{socket = undefined}) + end; + true -> + State + end. + +make_payload(State, Msg, Badge, Sound, Sender, CustomFields) -> + Msg2 = json_escape(Msg), + AlertPayload = + case Msg2 of + <<"">> -> <<"">>; + _ -> <<"\"alert\":\"", Msg2/binary, "\"">> + end, + BadgePayload = + case catch jlib:binary_to_integer(Badge) of + B when is_integer(B) -> + <<"\"badge\":", Badge/binary>>; + _ -> <<"">> + end, + SoundPayload = + case Sound of + <<"true">> -> + SoundFile = State#state.soundfile, + <<"\"sound\":\"", (json_escape(SoundFile))/binary, "\"">>; + _ -> <<"">> + end, + Payloads = lists:filter( + fun(S) -> S /= <<"">> end, + [AlertPayload, BadgePayload, SoundPayload]), + + CustomPayloadFields = + [<<"\"", (json_escape(Name))/binary, "\":\"", + (json_escape(Value))/binary, "\"">> + || {Name, Value} <- CustomFields] ++ + [<<"\"from\":\"", (json_escape(Sender))/binary, "\"">> || Sender /= <<"">>], + + Payload1 = + [<<"{">>, + str:join( + [<<"\"aps\":{", (str:join(Payloads, <<",">>))/binary, "}">> | CustomPayloadFields], + <<",">>), + <<"}">>], + Payload = list_to_binary(Payload1), + PayloadLen = size(Payload), + if + PayloadLen > ?MAX_PAYLOAD_SIZE -> + Delta = PayloadLen - ?MAX_PAYLOAD_SIZE, + MsgLen = size(Msg), + if + MsgLen /= 0 -> + CutMsg = + if + MsgLen > Delta -> + {CMsg, _} = split_binary(Msg, MsgLen - Delta), + CMsg; + true -> + <<"">> + end, + make_payload(State, CutMsg, Badge, Sound, Sender, CustomFields); + true -> + Payload2 = + <<"{\"aps\":{", (str:join(Payloads, <<",">>))/binary, "}}">>, + Payload2 + end; + true -> + Payload + end. + +connect(#state{socket = undefined, certfile_mtime = undefined} = State) -> + Gateway = State#state.gateway, + Port = State#state.port, + CertFile = State#state.certfile, + case ssl:connect(Gateway, Port, [{certfile, CertFile}, + {active, true}, + binary], + ?SSL_TIMEOUT) of + {ok, Socket} -> + {noreply, resend_messages(State#state{socket = Socket})}; + {error, Reason} -> + {Timeout, State2} = + case Reason of + esslconnect -> + MTime = get_mtime(CertFile), + case State#state.failure_script of + undefined -> + ok; + FailureScript -> + os:cmd(FailureScript ++ " " ++ Gateway) + end, + {?HANDSHAKE_TIMEOUT, + State#state{certfile_mtime = MTime}}; + _ -> + {?RECONNECT_TIMEOUT, State} + end, + ?ERROR_MSG("(~p) Connection to ~p:~p failed: ~p, " + "retrying after ~p seconds", + [State2#state.host, Gateway, Port, + Reason, Timeout div 1000]), + erlang:send_after(Timeout, self(), connect), + {noreply, State2} + end; +connect(#state{socket = undefined, certfile_mtime = MTime} = State) -> + CertFile = State#state.certfile, + case get_mtime(CertFile) of + MTime -> + Gateway = State#state.gateway, + Port = State#state.port, + Timeout = ?HANDSHAKE_TIMEOUT, + ?ERROR_MSG("(~p) Connection to ~p:~p postponed: " + "waiting for ~p update, " + "retrying after ~p seconds", + [State#state.host, Gateway, Port, + CertFile, Timeout div 1000]), + erlang:send_after(Timeout, self(), connect), + {noreply, State}; + _ -> + connect(State#state{certfile_mtime = undefined}) + end; +connect(State) -> + {noreply, State}. + +get_mtime(File) -> + case file:read_file_info(File) of + {ok, FileInfo} -> + FileInfo#file_info.mtime; + {error, _} -> + no_certfile + end. + +bounce_message(From, To, Packet, Reason) -> + #xmlel{attrs = Attrs} = Packet, + Type = xml:get_attr_s(<<"type">>, Attrs), + if Type /= <<"error">>; Type /= <<"result">> -> + ejabberd_router:route( + To, From, + jlib:make_error_reply( + Packet, + ?ERRT_INTERNAL_SERVER_ERROR( + xml:get_attr_s(<<"xml:lang">>, Attrs), + Reason))); + true -> + ok + end. + +queue_message(From, To, Packet, State) -> + case State#state.queue of + {?MAX_QUEUE_SIZE, Queue} -> + {{value, {From1, To1, Packet1}}, Queue1} = queue:out(Queue), + bounce_message(From1, To1, Packet1, + <<"Unable to connect to push service">>), + Queue2 = queue:in({From, To, Packet}, Queue1), + State#state{queue = {?MAX_QUEUE_SIZE, Queue2}}; + {Size, Queue} -> + Queue1 = queue:in({From, To, Packet}, Queue), + State#state{queue = {Size+1, Queue1}} + end. + +resend_messages(#state{queue = {_, Queue}} = State) -> + lists:foldl( + fun({From, To, Packet}, AccState) -> + case catch handle_message(From, To, Packet, AccState) of + {'EXIT', _} = Err -> + ?ERROR_MSG("error while processing message:~n" + "** From: ~p~n" + "** To: ~p~n" + "** Packet: ~p~n" + "** Reason: ~p", + [From, To, Packet, Err]), + AccState; + NewAccState -> + NewAccState + end + end, State#state{queue = {0, queue:new()}}, queue:to_list(Queue)). + +cache(JID, DeviceID, State) -> + CmdID = State#state.cmd_id, + Key = CmdID rem ?CACHE_SIZE, + C1 = State#state.cmd_cache, + D1 = State#state.device_cache, + D2 = case dict:find(Key, C1) of + {ok, {_, OldDeviceID}} -> + del_device_cache(D1, OldDeviceID); + error -> + D1 + end, + D3 = add_device_cache(D2, DeviceID, JID), + C2 = dict:store(Key, {JID, DeviceID}, C1), + State#state{cmd_id = CmdID + 1, + cmd_cache = C2, + device_cache = D3}. + +add_device_cache(DeviceCache, DeviceID, JID) -> + dict:update( + DeviceID, + fun({Counter, _}) -> {Counter + 1, JID} end, + {1, JID}, + DeviceCache). + +del_device_cache(DeviceCache, DeviceID) -> + case dict:find(DeviceID, DeviceCache) of + {ok, {Counter, JID}} -> + case Counter of + 1 -> + dict:erase(DeviceID, DeviceCache); + _ -> + dict:store(DeviceID, {Counter - 1, JID}, DeviceCache) + end; + error -> + DeviceCache + end. + +json_escape(S) -> + json_escape(S, <<>>). + +json_escape(<<>>, Res) -> + Res; +json_escape(<<C, S/binary>>, Res) -> + case C of + $" -> json_escape(S, <<Res/binary, "\\\"">>); + $\\ -> json_escape(S, <<Res/binary, "\\\\">>); + _ when C < 16 -> + B = list_to_binary(erlang:integer_to_list(C, 16)), + json_escape(S, <<Res/binary, "\\u000", B/binary>>); + _ when C < 32 -> + B = list_to_binary(erlang:integer_to_list(C, 16)), + json_escape(S, <<Res/binary, "\\u00", B/binary>>); + _ -> json_escape(S, <<Res/binary, C>>) + end. + + +iq_disco(Lang) -> + [#xmlel{name = <<"identity">>, + attrs = [{<<"category">>, <<"gateway">>}, + {<<"type">>, <<"apple">>}, + {<<"name">>, translate:translate( + Lang, <<"Apple Push Service">>)}], + children = []}, + #xmlel{name = <<"feature">>, + attrs = [{<<"var">>, ?NS_DISCO_INFO}], + children = []}]. + + +parse_feedback_buf(Buf, State) -> + case Buf of + <<TimeStamp:32, IDLen:16, BDeviceID:IDLen/binary, Rest/binary>> -> + IDLen8 = IDLen * 8, + <<DeviceID:IDLen8>> = BDeviceID, + ?INFO_MSG("(~p) received feedback for ~s~n", + [State#state.host, erlang:integer_to_list(DeviceID, 16)]), + case dict:find(DeviceID, State#state.device_cache) of + {ok, {_Counter, JID}} -> + ?INFO_MSG("(~p) sending feedback for ~s to ~s~n", + [State#state.host, + erlang:integer_to_list(DeviceID, 16), + jlib:jid_to_string(JID)]), + From = jlib:make_jid(<<"">>, State#state.host, <<"">>), + ejabberd_router:route( + From, JID, + #xmlel{name = <<"iq">>, + attrs = [{<<"id">>, <<"disable">>}, + {<<"type">>, <<"set">>}], + children = + [#xmlel{name = <<"disable">>, + attrs = + [{<<"xmlns">>, ?NS_P1_PUSH}, + {<<"status">>, <<"feedback">>}, + {<<"ts">>, jlib:integer_to_binary(TimeStamp)}, + {<<"id">>, jlib:integer_to_binary(DeviceID, 16)}], + children = []}]}); + error -> + ok + end, + parse_feedback_buf(Rest, State); + _ -> + Buf + end. + +iolist_to_string(S) -> + binary_to_list(iolist_to_binary(S)). |