xmpp.chapril.org-ejabberd/src/web/ejabberd_http_poll.erl

%%%----------------------------------------------------------------------
%%% File    : ejabberd_http_poll.erl
%%% Author  : Alexey Shchepin <alexey@sevcom.net>
%%% Purpose : HTTP Polling support (JEP-0025)
%%% Created :  4 Mar 2004 by Alexey Shchepin <alexey@sevcom.net>
%%% Id      : $Id$
%%%----------------------------------------------------------------------

-module(ejabberd_http_poll).
-author('alexey@sevcom.net').
-vsn('$Revision$ ').

-behaviour(gen_fsm).

%% External exports
-export([start_link/2,
	 init/1,
	 handle_event/3,
	 handle_sync_event/4,
	 code_change/4,
	 handle_info/3,
	 terminate/3,
	 send/2,
	 recv/3,
	 close/1,
	 process_request/1]).

-include("ejabberd.hrl").
-include("jlib.hrl").
-include("ejabberd_http.hrl").

-record(http_poll, {id, pid}).

-record(state, {id,
		key,
		output = "",
		input = "",
		waiting_input = false,
		timer}).

%-define(DBGFSM, true).

-ifdef(DBGFSM).
-define(FSMOPTS, [{debug, [trace]}]).
-else.
-define(FSMOPTS, []).
-endif.

-define(HTTP_POLL_TIMEOUT, 300000).
-define(CT, {"Content-Type", "text/xml; charset=utf-8"}).
-define(BAD_REQUEST, [?CT, {"Set-Cookie", "ID=-3:0; expires=-1"}]).


%%%----------------------------------------------------------------------
%%% API
%%%----------------------------------------------------------------------
start(ID, Key) ->
    mnesia:create_table(http_poll,
        		[{ram_copies, [node()]},
        		 {attributes, record_info(fields, http_poll)}]),
    supervisor:start_child(ejabberd_http_poll_sup, [ID, Key]).

start_link(ID, Key) ->
    gen_fsm:start_link(?MODULE, [ID, Key], ?FSMOPTS).

send({http_poll, FsmRef}, Packet) ->
    gen_fsm:sync_send_all_state_event(FsmRef, {send, Packet}).

recv({http_poll, FsmRef}, _Length, Timeout) ->
    gen_fsm:sync_send_all_state_event(FsmRef, recv, Timeout).

close({http_poll, FsmRef}) ->
    catch gen_fsm:sync_send_all_state_event(FsmRef, close).


process_request(#request{path = [],
			 data = Data} = Request) ->
    case catch parse_request(Data) of
	{ok, ID1, Key, NewKey, Packet} ->
	    ID = if
		     (ID1 == "0") or (ID1 == "mobile") ->
			 NewID = sha:sha(term_to_binary({now(), make_ref()})),
			 {ok, Pid} = start(NewID, ""),
			 mnesia:transaction(
			   fun() ->
				   mnesia:write(#http_poll{id = NewID,
							   pid = Pid})
			   end),
			 NewID;
		     true ->
			 ID1
		 end,
	    case http_put(ID, Key, NewKey, Packet) of
		{error, not_exists} ->
		    {200, ?BAD_REQUEST, ""};
		{error, bad_key} ->
		    {200, ?BAD_REQUEST, ""};
		ok ->
		    receive
		    after 100 -> ok
		    end,
		    case http_get(ID) of
			{error, not_exists} ->
			    {200, [?BAD_REQUEST], ""};
			{ok, OutPacket} ->
			    if
				ID == ID1 ->
				    Cookie = "ID=" ++ ID ++ "; expires=-1",
				    {200, [?CT, {"Set-Cookie", Cookie}],
				     OutPacket};
				ID1 == "mobile" ->
				    {200, [?CT], [ID, $\n, OutPacket]};
				true ->
				    Cookie = "ID=" ++ ID ++ "; expires=-1",
				    {200, [?CT, {"Set-Cookie", Cookie}],
				     OutPacket}
			    end
		    end
	    end;
	_ ->
	    {200, [?CT, {"Set-Cookie", "ID=-2:0; expires=-1"}], ""}
    end;
process_request(_Request) ->
    {400, [], {xmlelement, "h1", [],
	       [{xmlcdata, "400 Bad Request"}]}}.

%%%----------------------------------------------------------------------
%%% Callback functions from gen_fsm
%%%----------------------------------------------------------------------

%%----------------------------------------------------------------------
%% Func: init/1
%% Returns: {ok, StateName, StateData}          |
%%          {ok, StateName, StateData, Timeout} |
%%          ignore                              |
%%          {stop, StopReason}                   
%%----------------------------------------------------------------------
init([ID, Key]) ->
    ?INFO_MSG("started: ~p", [{ID, Key}]),
    Opts = [], % TODO
    ejabberd_c2s:start({?MODULE, {http_poll, self()}}, Opts),
    Timer = erlang:start_timer(?HTTP_POLL_TIMEOUT, self(), []),
    {ok, loop, #state{id = ID,
		      key = Key,
		      timer = Timer}}.

%%----------------------------------------------------------------------
%% Func: StateName/2
%% Returns: {next_state, NextStateName, NextStateData}          |
%%          {next_state, NextStateName, NextStateData, Timeout} |
%%          {stop, Reason, NewStateData}                         
%%----------------------------------------------------------------------


%%----------------------------------------------------------------------
%% Func: StateName/3
%% Returns: {next_state, NextStateName, NextStateData}            |
%%          {next_state, NextStateName, NextStateData, Timeout}   |
%%          {reply, Reply, NextStateName, NextStateData}          |
%%          {reply, Reply, NextStateName, NextStateData, Timeout} |
%%          {stop, Reason, NewStateData}                          |
%%          {stop, Reason, Reply, NewStateData}                    
%%----------------------------------------------------------------------
%state_name(Event, From, StateData) ->
%    Reply = ok,
%    {reply, Reply, state_name, StateData}.

%%----------------------------------------------------------------------
%% Func: handle_event/3
%% Returns: {next_state, NextStateName, NextStateData}          |
%%          {next_state, NextStateName, NextStateData, Timeout} |
%%          {stop, Reason, NewStateData}                         
%%----------------------------------------------------------------------
handle_event(Event, StateName, StateData) ->
    {next_state, StateName, StateData}.

%%----------------------------------------------------------------------
%% Func: handle_sync_event/4
%% Returns: {next_state, NextStateName, NextStateData}            |
%%          {next_state, NextStateName, NextStateData, Timeout}   |
%%          {reply, Reply, NextStateName, NextStateData}          |
%%          {reply, Reply, NextStateName, NextStateData, Timeout} |
%%          {stop, Reason, NewStateData}                          |
%%          {stop, Reason, Reply, NewStateData}                    
%%----------------------------------------------------------------------
handle_sync_event({send, Packet}, From, StateName, StateData) ->
    Output = [StateData#state.output | Packet],
    Reply = ok,
    {reply, Reply, StateName, StateData#state{output = Output}};

handle_sync_event(recv, From, StateName, StateData) ->
    case StateData#state.input of
	"" ->
	    {next_state, StateName, StateData#state{waiting_input = From}};
	Input ->
	    Reply = {ok, list_to_binary(Input)},
	    {reply, Reply, StateName, StateData#state{input = "",
						      waiting_input = false}}
    end;

handle_sync_event(stop, From, StateName, StateData) ->
    Reply = ok,
    {stop, normal, Reply, StateData};

handle_sync_event({http_put, Key, NewKey, Packet},
		  From, StateName, StateData) ->
    Allow = case StateData#state.key of
		"" ->
		    true;
		OldKey ->
		    NextKey = jlib:encode_base64(
				binary_to_list(crypto:sha(Key))),
		    if
			OldKey == NextKey ->
			    true;
			true ->
			    false
		    end
	    end,
    if
	Allow ->
	    case StateData#state.waiting_input of
		false ->
		    Input = [StateData#state.input | Packet],
		    Reply = ok,
		    {reply, Reply, StateName, StateData#state{input = Input,
							      key = NewKey}};
		Receiver ->
		    gen_fsm:reply(Receiver, {ok, list_to_binary(Packet)}),
		    cancel_timer(StateData#state.timer),
		    Timer = erlang:start_timer(?HTTP_POLL_TIMEOUT, self(), []),
		    Reply = ok,
		    {reply, Reply, StateName,
		     StateData#state{waiting_input = false,
				     key = NewKey,
				     timer = Timer}}
	    end;
	true ->
	    Reply = {error, bad_key},
	    {reply, Reply, StateName, StateData}
    end;

handle_sync_event(http_get, From, StateName, StateData) ->
    Reply = {ok, StateData#state.output},
    {reply, Reply, StateName, StateData#state{output = ""}};

handle_sync_event(Event, From, StateName, StateData) ->
    Reply = ok,
    {reply, Reply, StateName, StateData}.

code_change(OldVsn, StateName, StateData, Extra) ->
    {ok, StateName, StateData}.

%%----------------------------------------------------------------------
%% Func: handle_info/3
%% Returns: {next_state, NextStateName, NextStateData}          |
%%          {next_state, NextStateName, NextStateData, Timeout} |
%%          {stop, Reason, NewStateData}                         
%%----------------------------------------------------------------------
handle_info({timeout, Timer, _}, StateName,
	    #state{timer = Timer} = StateData) ->
    {stop, normal, StateData};

handle_info(_, StateName, StateData) ->
    {next_state, StateName, StateData}.

%%----------------------------------------------------------------------
%% Func: terminate/3
%% Purpose: Shutdown the fsm
%% Returns: any
%%----------------------------------------------------------------------
terminate(Reason, StateName, StateData) ->
    mnesia:transaction(
      fun() ->
	      mnesia:delete({http_poll, StateData#state.id})
      end),
    case StateData#state.waiting_input of
	false ->
	    ok;
	Receiver ->
	    gen_fsm:reply(Receiver, {error, closed})
    end,
    ok.

%%%----------------------------------------------------------------------
%%% Internal functions
%%%----------------------------------------------------------------------


http_put(ID, Key, NewKey, Packet) ->
    case mnesia:dirty_read({http_poll, ID}) of
	[] ->
	    {error, not_exists};
	[#http_poll{pid = FsmRef}] ->
	    gen_fsm:sync_send_all_state_event(
	      FsmRef, {http_put, Key, NewKey, Packet})
    end.

http_get(ID) ->
    case mnesia:dirty_read({http_poll, ID}) of
	[] ->
	    {error, not_exists};
	[#http_poll{pid = FsmRef}] ->
	    gen_fsm:sync_send_all_state_event(FsmRef, http_get)
    end.


parse_request(Data) ->
    Comma = string:chr(Data, $,),
    Header = lists:sublist(Data, Comma - 1),
    Packet = lists:nthtail(Comma, Data),
    {ID, Key, NewKey} =
	case string:tokens(Header, ";") of
	    [ID1] ->
		{ID1, "", ""};
	    [ID1, Key1] ->
		{ID1, Key1, Key1};
	    [ID1, Key1, NewKey1] ->
		{ID1, Key1, NewKey1}
	end,
    {ok, ID, Key, NewKey, Packet}.


cancel_timer(Timer) ->
    erlang:cancel_timer(Timer),
    receive
	{timeout, Timer, _} ->
	    ok
    after 0 ->
	    ok
    end.