/**
* Deletes cached events that are no longer needed by the component.
*
* @access protected To be used from eventslib only
*
* @param string $component examples: 'moodle', 'mod_forum', 'block_quiz_results'
* @param array $cachedhandlers array of the cached events definitions that will be
* @return int number of unused handlers that have been removed
*/
function events_cleanup($component, $cachedhandlers)
{
global $DB;
$deletecount = 0;
foreach ($cachedhandlers as $eventname => $cachedhandler) {
if ($qhandlers = $DB->get_records('events_queue_handlers', array('handlerid' => $cachedhandler['id']))) {
//debugging("Removing pending events from queue before deleting of event handler: $component - $eventname");
foreach ($qhandlers as $qhandler) {
events_dequeue($qhandler);
}
}
$DB->delete_records('events_handlers', array('eventname' => $eventname, 'component' => $component));
$deletecount++;
}
return $deletecount;
}
/**
* given a queued handler, call the respective event handler to process the event
*
* @access protected To be used from eventslib only
* @deprecated since Moodle 3.1
* @param stdClass $qhandler events_queued_handler row from db
* @return boolean true means event processed, false means retry later, NULL means fatal failure
*/
function events_process_queued_handler($qhandler)
{
global $DB;
// get handler
if (!($handler = $DB->get_record('events_handlers', array('id' => $qhandler->handlerid)))) {
debugging("Error processing queue handler {$qhandler->id}, missing handler id: {$qhandler->handlerid}");
//irrecoverable error, remove broken queue handler
events_dequeue($qhandler);
return NULL;
}
// get event object
if (!($event = $DB->get_record('events_queue', array('id' => $qhandler->queuedeventid)))) {
// can't proceed with no event object - might happen when two crons running at the same time
debugging("Error processing queue handler {$qhandler->id}, missing event id: {$qhandler->queuedeventid}");
//irrecoverable error, remove broken queue handler
events_dequeue($qhandler);
return NULL;
}
// call the function specified by the handler
try {
$errormessage = 'Unknown error';
if (events_dispatch($handler, unserialize(base64_decode($event->eventdata)), $errormessage)) {
//everything ok
events_dequeue($qhandler);
return true;
}
} catch (Exception $e) {
// the problem here is that we do not want one broken handler to stop all others,
// cron handlers are very tricky because the needed data might have been deleted before the cron execution
$errormessage = "Handler function of component {$handler->component}: {$handler->handlerfunction} threw exception :" . $e->getMessage() . "\n" . format_backtrace($e->getTrace(), true);
if (!empty($e->debuginfo)) {
$errormessage .= $e->debuginfo;
}
}
//dispatching failed
$qh = new stdClass();
$qh->id = $qhandler->id;
$qh->errormessage = $errormessage;
$qh->timemodified = time();
$qh->status = $qhandler->status + 1;
$DB->update_record('events_queue_handlers', $qh);
debugging($errormessage);
return false;
}
/**
* given a queued handler, call the respective event handler to process the event
*
* INTERNAL - to be used from eventslib only
*
* @global object
* @global object
* @param object $qhandler events_queued_handler object from db
* @return boolean meaning success, or NULL on fatal failure
*/
function events_process_queued_handler($qhandler)
{
global $CFG, $DB;
// get handler
if (!($handler = $DB->get_record('events_handlers', array('id' => $qhandler->handlerid)))) {
debugging("Error processing queue handler {$qhandler->id}, missing handler id: {$qhandler->handlerid}");
//irrecoverable error, remove broken queue handler
events_dequeue($qhandler);
return NULL;
}
// get event object
if (!($event = $DB->get_record('events_queue', array('id' => $qhandler->queuedeventid)))) {
// can't proceed with no event object - might happen when two crons running at the same time
debugging("Error processing queue handler {$qhandler->id}, missing event id: {$qhandler->queuedeventid}");
//irrecoverable error, remove broken queue handler
events_dequeue($qhandler);
return NULL;
}
// call the function specified by the handler
$errormessage = 'Unknown error';
if (events_dispatch($handler, unserialize(base64_decode($event->eventdata)), $errormessage)) {
//everything ok
events_dequeue($qhandler);
return true;
} else {
//dispatching failed
$qh = new object();
$qh->id = $qhandler->id;
$qh->errormessage = $errormessage;
$qh->timemodified = time();
$qh->status = $qhandler->status + 1;
$DB->update_record('events_queue_handlers', $qh);
return false;
}
}