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MDL-9848 eventslib improvements and cleanup

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This commit is contained in:
skodak 2007-05-22 10:26:29 +00:00
parent cd26d8e047
commit d46306de6a
10 changed files with 534 additions and 227 deletions
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450
lib/eventslib.php
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@ -23,6 +23,9 @@ function events_load_def($component) {
if ($component == 'moodle') {
$defpath = $CFG->libdir.'/db/events.php';
} else if ($component == 'unittest') {
$defpath = $CFG->libdir.'/simpletest/fixtures/events.php';
} else {
$compparts = explode('/', $component);
@ -41,7 +44,7 @@ function events_load_def($component) {
}
}
$events = array();
$events = array(); // TODO: $handlers might be better here ;-)
if (file_exists($defpath)) {
require($defpath);
@ -58,93 +61,97 @@ function events_load_def($component) {
*
* INTERNAL - to be used from eventslib only
*/
function get_cached_events($component) {
$cachedevents = array();
function events_get_cached($component) {
$cachedhandlers = array();
if ($storedevents = get_records('events_handlers', 'handlermodule', $component)) {
foreach ($storedevents as $event) {
$cachedevents[$event->eventname] = array (
'id' => $event->id,
'handlerfile' => $event->handlerfile,
'handlerfunction' => $event->handlerfunction,
'schedule' => $event->schedule);
if ($storedhandlers = get_records('events_handlers', 'handlermodule', $component)) {
foreach ($storedhandlers as $handler) {
$cachedhandlers[$handler->eventname] = array (
'id' => $handler->id,
'handlerfile' => $handler->handlerfile,
'handlerfunction' => $handler->handlerfunction,
'schedule' => $handler->schedule);
}
}
return $cachedevents;
return $cachedhandlers;
}
/**
* We can not removed all event handlers in table, then add them again
* because event handlers could be referenced by queued items
*
* Updates the capabilities table with the component capability definitions.
* If no parameters are given, the function updates the core moodle
* capabilities.
*
* Note that the absence of the db/events.php event definition file
* will cause any stored events for the component to be removed from
* will cause any queued events for the component to be removed from
* the database.
*
* @param $component - examples: 'moodle', 'mod/forum', 'block/quiz_results'
* @return boolean
*/
function events_update_definition($component='moodle') {
// load event definition from events.php
$fileevents = events_load_def($component);
$filehandlers = events_load_def($component);
// load event definitions from db tables
// if we detect an event being already stored, we discard from this array later
// the remaining needs to be removed
$cachedevents = get_cached_events($component);
$cachedhandlers = events_get_cached($component);
foreach ($fileevents as $eventname => $fileevent) {
if (!empty($cachedevents[$eventname])) {
if ($cachedevents[$eventname]['handlerfile'] == $fileevent['handlerfile'] &&
$cachedevents[$eventname]['handlerfunction'] == $fileevent['handlerfunction'] &&
$cachedevents[$eventname]['schedule'] == $fileevent['schedule']) {
foreach ($filehandlers as $eventname => $filehandler) {
if (!empty($cachedhandlers[$eventname])) {
if ($cachedhandlers[$eventname]['handlerfile'] == $filehandler['handlerfile'] &&
$cachedhandlers[$eventname]['handlerfunction'] == serialize($filehandler['handlerfunction']) &&
$cachedhandlers[$eventname]['schedule'] == $filehandler['schedule']) {
// exact same event handler already present in db, ignore this entry
unset($cachedevents[$eventname]);
unset($cachedhandlers[$eventname]);
continue;
} else {
// same event name matches, this event has been updated, update the datebase
$event = new object();
$event->id = $cachedevents[$eventname]['id'];
$event->handlerfile = $fileevent['handlerfile'];
$event->handlerfunction = $fileevent['handlerfunction'];
$event->schedule = $fileevent['schedule'];
$handler = new object();
$handler->id = $cachedhandlers[$eventname]['id'];
$handler->handlerfile = $filehandler['handlerfile'];
$handler->handlerfunction = serialize($filehandler['handlerfunction']); // static class methods stored as array
$handler->schedule = $filehandler['schedule'];
update_record('events_handlers', $event);
update_record('events_handlers', $handler);
unset($cachedevents[$eventname]);
unset($cachedhandlers[$eventname]);
continue;
}
} else {
// if we are here, this event handler is not present in db (new)
// add it
$event = new object();
$event->eventname = $eventname;
$event->handlermodule = $component;
$event->handlerfile = $fileevent['handlerfile'];
$event->handlerfunction = $fileevent['handlerfunction'];
$event->schedule = $fileevent['schedule'];
$handler = new object();
$handler->eventname = $eventname;
$handler->handlermodule = $component;
$handler->handlerfile = $filehandler['handlerfile'];
$handler->handlerfunction = serialize($filehandler['handlerfunction']); // static class methods stored as array
$handler->schedule = $filehandler['schedule'];
insert_record('events_handlers', $event);
insert_record('events_handlers', $handler);
}
}
// clean up the left overs, the entries in cachedevents array at this points are deprecated event handlers
// and should be removed, delete from db
events_cleanup($component, $cachedevents);
events_cleanup($component, $cachedhandlers);
return true;
}
/**
* Remove all event handlers and queued events
* @param $component - examples: 'moodle', 'mod/forum', 'block/quiz_results'
*/
function events_uninstall($component) {
$cachedhandlers = events_get_cached($component);
events_cleanup($component, $cachedhandlers);
}
/**
* Deletes cached events that are no longer needed by the component.
* @param $component - examples: 'moodle', 'mod/forum', 'block/quiz_results'
@ -153,9 +160,15 @@ function events_update_definition($component='moodle') {
*
* INTERNAL - to be used from eventslib only
*/
function events_cleanup($component, $cachedevents) {
function events_cleanup($component, $cachedhandlers) {
$deletecount = 0;
foreach ($cachedevents as $eventname => $cachedevent) {
foreach ($cachedhandlers as $eventname => $cachedhandler) {
if ($qhandlers = get_records('events_queue_handlers', 'handlerid', $cachedhandler['id'])) {
debugging("Removing pending events from queue before deleting of event handler: $component - $eventname");
foreach ($qhandlers as $qhandler) {
events_dequeue($qhandler);
}
}
if (delete_records('events_handlers', 'eventname', $eventname, 'handlermodule', $component)) {
$deletecount++;
}
@ -169,162 +182,293 @@ function events_cleanup($component, $cachedevents) {
* puts a handler on queue
* @param object handler - event handler object from db
* @param object eventdata - event data object
* @param bool failed - whether this handler is queued because of a failed event trigger
* @return
* @return id number of new queue handler
*
* INTERNAL - to be used from eventslib only
*/
function queue_handler($handler, $eventid) {
global $USER;
function events_queue_handler($handler, $event, $errormessage) {
// check if this event handler is already queued
if (!$qh = get_record('events_queue_handlers', 'queuedeventid', $eventid, 'handlerid', $handler->id)) {
// make a new one
$qh = new object;
$qh->queuedeventid = $eventid;
$qh->handlerid = $handler->id;
$qh->status = 0;
$qh->errormessage = '';
$qh->timemodified = time();
return insert_record('events_queue_handlers', $qh);
if ($qhandler = get_record('events_queue_handlers', 'queuedeventid', $event->id, 'handlerid', $handler->id)) {
debugging("Please check code: Event id $event->id is already queued in handler id $qhandler->id");
return $qhandler->id;
}
// make a new queue handler
$qhandler = new object();
$qhandler->queuedeventid = $event->id;
$qhandler->handlerid = $handler->id;
$qhandler->errormessage = addslashes($errormessage);
$qhandler->timemodified = time();
if ($handler->schedule == 'instant' and $handler->status == 1) {
$qhandler->status = 1; //already one failed attempt to dispatch this event
} else {
// update existing one, failed again
$qh->states++;
$qh->timemodified = time();
update_record('events_queue_handlers', $qh);
return -1; // failed
$qhandler->status = 0;
}
}
/**
* function to call all eventhandlers when triggering an event
* @param eventname - name of the event
* @param eventdata - event data object
* @return number of failed events
*/
function trigger_event($eventname, $eventdata) {
$failedevent = 0; // number of failed events.
$eventid = 0;
// pull out all registered event handlers
if ($handlers = get_records('events_handlers', 'eventname', $eventname)) {
foreach ($handlers as $handler) {
// either excute it now
// if event type is
if ($handler->schedule == 'instant') {
if (dispatch_event($handler, $eventdata)) {
continue;
} else {
// update the failed flag
$failedevent ++;
}
}
// if even type is not instant, or trigger failed, queue it
$queuedevent++;
// make and queue the event object here
if (!$eventid) {
$eq = new object;
$eq->userid = $USER->id;
$eq->schedule = $eventdata->schedule;
$eq->eventdata = serialize($eventdata);
$eq->stackdump = '';
$eq->timecreated = time();
$eventid = insert_record('events_queue', $eq);
}
queue_handler($handler, $eventid);
}
}
return $failedevent;
return insert_record('events_queue_handlers', $qhandler);
}
/**
* trigger a single event with a specified handler
* @param handler - hander object from db
* @param eventdata - event dataobject
* @param errormessage - error message indicating problem
* @return bool - success or fail
*
* INTERNAL - to be used from eventslib only
*/
function dispatch_event($handler, $eventdata) {
function events_dispatch($handler, $eventdata, &$errormessage) {
global $CFG;
$function = unserialize($handler->handlerfunction);
if (is_callable($function)) {
// oki, no need for includes
} else if (file_exists($CFG->dirroot.$handler->handlerfile)) {
include_once($CFG->dirroot.$handler->handlerfile);
} else {
$errormessage = "Handler file of component $handler->handlermodule: $handler->handlerfile can not be found!";
return false;
}
// checks for handler validity
if (is_callable($function)) {
return call_user_func($function, $eventdata);
// check if the same handler is queued already, if so, return false so we can queue it
// TODO
include_once($CFG->dirroot.$handler->handlerfile);
return call_user_func($handler->handlerfunction, $eventdata);
} else {
$errormessage = "Handler function of component $handler->handlermodule: $handler->handlerfunction not callable function or class method!";
return false;
}
}
/**
* given a queued handler, call the respective event handler to process the event
* @param object handler- events_queued_handler object from db
* @return fail or custom function value
* @param object qhandler - events_queued_handler object from db
* @return boolean meaning success, or NULL on fatal failure
*
* INTERNAL - to be used from eventslib only
*/
function events_process_queued_handler($handler) {
// checks for handler validity
function events_process_queued_handler($qhandler) {
global $CFG;
// get handler
if (!$eventhandler = get_record('events_handlers', 'id', $handler->handlerid)) {
// can't proceed with no handler
return false;
if (!$handler = get_record('events_handlers', '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 (!$eventobject = get_record('events_queue', 'id', $handler->queuedeventid)) {
// can't proceed with no event object
return false;
if (!$event = get_record('events_queue', '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 sepcified by the handler
return dispatch_event($eventhandler, unserialize($eventobject->eventdata));
}
// call the function specified by the handler
$errormessage = 'Unknown error';
if (events_dispatch($handler, unserialize($event->eventdata), $errormessage)) {
//everything ok
events_dequeue($qhandler);
return true;
/**
* Events cron will try to empty the events queue by processing all the queued events handlers
*/
function events_cron() {
global $CFG;
if ($handlers = get_records_select('events_queue_handlers', '', 'timemodified')) {
foreach ($handlers as $handler) {
if (events_process_queued_handler($handler)) {
// dequeue();
events_dequeue($handler);
} else {
// failed again, put back on queue
$handler->timemodified = time();
$handler->status++;
update_record('events_queue_handlers', $handler);
}
}
} else {
//dispatching failed
$qh = new object();
$qh->id = $qhandler->id;
$qh->errormessage = addslashes($errormessage);
$qh->timemodified = time();
$qh->status = $qhandler->status + 1;
update_record('events_queue_handlers', $qh);
return false;
}
}
/**
* removes this queued handler from the events_queued_handler table
* removes events_queue record from events_queue if no more references to this event object exists
* @input object handler - events_queued_handler object from db
* @param object qhandler - events_queued_handler object from db
*
* INTERNAL - to be used from eventslib only
*/
function events_dequeue($handler) {
function events_dequeue($qhandler) {
// first delete the queue handler
delete_records('events_queue_handlers', 'id', $qhandler->id);
if (delete_records('events_queue_handlers', 'id', $handler->id)) {
// if no more queued handler is pointing to the same event
if (!record_exists('events_queue_handlers', 'queuedeventid', $handler->queuedeventid)) {
delete_records('events_queue', 'id', $handler->queuedeventid);
}
return true;
} else {
return false;
// if no more queued handler is pointing to the same event - delete the event too
if (!record_exists('events_queue_handlers', 'queuedeventid', $qhandler->queuedeventid)) {
delete_records('events_queue', 'id', $qhandler->queuedeventid);
}
}
/****** Public events API starts here, do not use functions above in 3rd party code ******/
/**
* Events cron will try to empty the events queue by processing all the queued events handlers
* @param string eventname - empty means all
* @return number of dispatched+removed broken events
*
* PUBLIC
*/
function events_cron($eventname='') {
global $CFG;
$failed = array();
$processed = 0;
if ($eventname) {
$sql = "SELECT qh.* FROM {$CFG->prefix}events_queue_handlers qh, {$CFG->prefix}events_handlers h
WHERE qh.handlerid = h.id AND h.eventname='$eventname'
ORDER BY qh.id";
} else {
$sql = "SELECT * FROM {$CFG->prefix}events_queue_handlers
ORDER BY id";
}
if ($rs = get_recordset_sql($sql)) {
if ($rs->RecordCount() > 0) {
while ($qhandler = rs_fetch_next_record($rs)) {
if (in_array($qhandler->handlerid, $failed)) {
// do not try to dispatch any later events when one already failed
continue;
}
$status = events_process_queued_handler($qhandler);
if ($status === false) {
$failed[] = $qhandler->handlerid;
} else {
$processed++;
}
}
}
rs_close($rs);
}
return $processed;
}
/**
* Function to call all eventhandlers when triggering an event
* @param eventname - name of the event
* @param eventdata - event data object
* @return number of failed events
*
* PUBLIC
*/
function events_trigger($eventname, $eventdata) {
global $CFG, $USER;
$failedcount = 0; // number of failed events.
$event = false;
// pull out all registered event handlers
if ($handlers = get_records('events_handlers', 'eventname', $eventname)) {
foreach ($handlers as $handler) {
$errormessage = '';
if ($handler->schedule == 'instant') {
if ($handler->status) {
//check if previous pending events processed
if (!record_exists('events_queue_handlers', 'handlerid', $handler->id)) {
// ok, queue is empty, lets reset the status back to 0 == ok
$handler->status = 0;
set_field('events_handlers', 'status', 0, 'id', $handler->id);
}
}
// dispatch the event only if instant schedule and status ok
if (!$handler->status) {
$errormessage = 'Unknown error';;
if (events_dispatch($handler, $eventdata, $errormessage)) {
continue;
}
// set error count to 1 == send next instant into cron queue
set_field('events_handlers', 'status', 1, 'id', $handler->id);
} else {
// increment the error status counter
$handler->status++;
set_field('events_handlers', 'status', $handler->status, 'id', $handler->id);
}
// update the failed counter
$failedcount ++;
} else if ($handler->schedule == 'cron') {
//ok - use queuing of events only
} else {
// unknown schedule - fallback to cron type
debugging("Unknown handler schedule type: $handler->schedule");
}
// if even type is not instant, or dispatch failed, queue it
if ($event === false) {
$event = new object();
$event->userid = $USER->id;
$event->eventdata = serialize($eventdata);
$event->timecreated = time();
if (debugging()) {
$dump = '';
$callers = debug_backtrace();
foreach ($callers as $caller) {
$dump .= 'line ' . $caller['line'] . ' of ' . substr($caller['file'], strlen($CFG->dirroot) + 1);
if (isset($caller['function'])) {
$dump .= ': call to ';
if (isset($caller['class'])) {
$dump .= $caller['class'] . $caller['type'];
}
$dump .= $caller['function'] . '()';
}
$dump .= "\n";
}
$event->stackdump = addslashes($dump);
} else {
$event->stackdump = '';
}
$event->id = insert_record('events_queue', $event);
}
events_queue_handler($handler, $event, $errormessage);
}
} else {
debugging("No handler found for event: $eventname");
}
return $failedcount;
}
/**
* checks if an event is registered for this component
* @param string eventname - name of the event
* @param string component - component name, can be mod/data or moodle
* @return bool
*
* PUBLIC
*/
function event_is_registered($component, $eventname) {
function events_is_registered($eventname, $component) {
return record_exists('events_handlers', 'handlermodule', $component, 'eventname', $eventname);
}
/**
* checks if an event is queued for processing - either cron handlers attached or failed instant handlers
* @param string eventname - name of the event
* @return int number of queued events
*
* PUBLIC
*/
function events_pending_count($eventname) {
global $CFG;
$sql = "SELECT COUNT(*) FROM {$CFG->prefix}events_queue_handlers qh, {$CFG->prefix}events_handlers h
WHERE qh.handlerid = h.id AND h.eventname='$eventname'";
return count_records_sql($sql);
}
?>