Libevent timeout loop exit - php

Question

I'm having some difficulties getting the PHP libevent extension to break out of a loop on a timeout. Here's what I've got so far based on the demos on the PHP.net docs pages:
// From here: http://www.php.net/manual/en/libevent.examples.php
function print_line($fd, $events, $arg) {
static $max_requests = 0;
$max_requests++;
printf("Received event: %s after %s\n%s", implode(getEventFlags($events)), getTimer(), fgets($fd));
if ($max_requests == 10) {
// exit loop after 3 writes
echo " [EXIT]\n";
event_base_loopexit($arg[1]);
}
}
// create base and event
$base = event_base_new();
$event = event_new();
getTimer(); // Initialise time
$fd = STDIN;
event_set($event, $fd, EV_READ | EV_PERSIST, "print_line", array($event, $base));
event_base_set($event, $base);
event_add($event, 2000000);
event_base_loop($base);
// extract flags from bitmask
function getEventFlags ($ebm) {
$expFlags = array('EV_TIMEOUT', 'EV_SIGNAL', 'EV_READ', 'EV_WRITE', 'EV_PERSIST');
$ret = array();
foreach ($expFlags as $exf) {
if ($ebm & constant($exf)) {
$ret[] = $exf;
}
}
return $ret;
}
// Used to track time!
function getTimer () {
static $ts;
if (is_null($ts)) {
$ts = microtime(true);
return "Timer initialised";
}
$newts = microtime(true);
$r = sprintf("Delta: %.3f", $newts - $ts);
$ts = $newts;
return $r;
}
I can see that the timeout value passed to event_add effects the events passed to print_line(), if these events are any more than 2 seconds apart I get an EV_TIMEOUT instead of an EV_READ. What I want however is for libevent to call print_line as soon as the timeout is reached rather than waiting for the next event in order to give me the timeout.
I've tried using event_base_loopexit($base, 2000000), this causes the event loop to exit immediately without blocking for events. I've also tried passing EV_TIMEOUT to event_set, this seems to have no effect at all.
Has anyone managed to get this working before? I know that the event_buffer_* stuff works with timeouts, however I want to use the standard event_base functions. One of the PECL bugs talks about event_timer_* functions and these functions do exist on my system, however they're not documented at all.

Answer 1

Problem is in fgets() in:
printf("Received event: %s after %s\n%s", implode(getEventFlags($events)), getTimer(), fgets($fd));
This blocks processing and waits for data from STDIN (but there are none on timeout)
Change to something like that:
$text = '';
if ($events & EV_READ) {
$text = fgets($fd);
}
printf("Received event: %s after %s\n%s", implode(getEventFlags($events)), getTimer(), $text);