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%%%----------------------------------------------------------------------
%%% File : server_sent_events.erl
%%% Author : Steve Vinoski <vinoski@ieee.org>
%%% Purpose : Server-Sent Events example
%%% Created : 1 June 2012 by Steve Vinoski <vinoski@ieee.org>
%%%----------------------------------------------------------------------
-module(server_sent_events).
-behaviour(gen_server).
-include("yaws_api.hrl").
%% API
-export([out/1]).
%% gen_server callbacks
-export([init/1, handle_call/3, handle_cast/2, handle_info/2,
terminate/2, code_change/3]).
-record(state, {
sock,
yaws_pid,
timer
}).
out(A) ->
case (A#arg.req)#http_request.method of
'GET' ->
case yaws_api:get_header(A#arg.headers, accept) of
undefined ->
{status, 406};
Accept ->
case string:str(Accept, "text/event-stream") of
0 ->
{status, 406};
_ ->
{ok, Pid} = gen_server:start(?MODULE, [A], []),
yaws_sse:headers(Pid)
end
end;
_ ->
[{status, 405},
{header, {"Allow", "GET"}}]
end.
init([Arg]) ->
process_flag(trap_exit, true),
{ok, #state{sock=Arg#arg.clisock}}.
handle_call(_Request, _From, State) ->
{reply, ok, State}.
handle_cast(_Msg, State) ->
{noreply, State}.
handle_info({ok, YawsPid}, State) ->
{ok, Timer} = timer:send_interval(1000, self(), tick),
{noreply, State#state{yaws_pid=YawsPid, timer=Timer}};
handle_info({discard, _YawsPid}, State) ->
%% nothing to do
{stop, normal, State};
handle_info(tick, #state{sock=Socket}=State) ->
Time = erlang:localtime(),
Data = yaws_sse:data(httpd_util:rfc1123_date(Time)),
case yaws_sse:send_events(Socket, Data) of
ok ->
{noreply, State};
{error, closed} ->
{stop, normal, State};
{error, Reason} ->
{stop, Reason, State}
end;
handle_info({tcp_closed, _}, State) ->
{stop, normal, State#state{sock=closed}};
handle_info(_Info, State) ->
{noreply, State}.
terminate(_Reason, #state{sock=Socket, yaws_pid=YawsPid, timer=Timer}) ->
case Timer of
undefined ->
ok;
_ ->
timer:cancel(Timer)
end,
yaws_api:stream_process_end(Socket, YawsPid),
ok.
code_change(_OldVsn, State, _Extra) ->
{ok, State}.
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