mirror of
https://github.com/moodle/moodle.git
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618 lines
22 KiB
PHP
618 lines
22 KiB
PHP
<?php
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// This file is part of Moodle - http://moodle.org/
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//
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// Moodle is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// Moodle is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with Moodle. If not, see <http://www.gnu.org/licenses/>.
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/**
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* Library of functions for events manipulation.
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*
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* The public API is all at the end of this file.
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*
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* @package core
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* @copyright 1999 onwards Martin Dougiamas {@link http://moodle.com}
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* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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*/
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defined('MOODLE_INTERNAL') || die();
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/**
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* Loads the events definitions for the component (from file). If no
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* events are defined for the component, we simply return an empty array.
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*
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* @access protected To be used from eventslib only
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*
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* @param string $component examples: 'moodle', 'mod_forum', 'block_quiz_results'
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* @return array Array of capabilities or empty array if not exists
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*/
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function events_load_def($component) {
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global $CFG;
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if ($component === 'unittest') {
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$defpath = $CFG->dirroot.'/lib/tests/fixtures/events.php';
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} else {
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$defpath = core_component::get_component_directory($component).'/db/events.php';
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}
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$handlers = array();
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if (file_exists($defpath)) {
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require($defpath);
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}
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// make sure the definitions are valid and complete; tell devs what is wrong
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foreach ($handlers as $eventname => $handler) {
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if ($eventname === 'reset') {
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debugging("'reset' can not be used as event name.");
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unset($handlers['reset']);
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continue;
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}
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if (!is_array($handler)) {
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debugging("Handler of '$eventname' must be specified as array'");
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unset($handlers[$eventname]);
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continue;
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}
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if (!isset($handler['handlerfile'])) {
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debugging("Handler of '$eventname' must include 'handlerfile' key'");
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unset($handlers[$eventname]);
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continue;
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}
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if (!isset($handler['handlerfunction'])) {
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debugging("Handler of '$eventname' must include 'handlerfunction' key'");
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unset($handlers[$eventname]);
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continue;
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}
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if (!isset($handler['schedule'])) {
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$handler['schedule'] = 'instant';
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}
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if ($handler['schedule'] !== 'instant' and $handler['schedule'] !== 'cron') {
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debugging("Handler of '$eventname' must include valid 'schedule' type (instant or cron)'");
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unset($handlers[$eventname]);
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continue;
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}
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if (!isset($handler['internal'])) {
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$handler['internal'] = 1;
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}
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$handlers[$eventname] = $handler;
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}
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return $handlers;
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}
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/**
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* Gets the capabilities that have been cached in the database for this
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* component.
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*
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* @access protected To be used from eventslib only
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*
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* @param string $component examples: 'moodle', 'mod_forum', 'block_quiz_results'
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* @return array of events
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*/
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function events_get_cached($component) {
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global $DB;
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$cachedhandlers = array();
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if ($storedhandlers = $DB->get_records('events_handlers', array('component'=>$component))) {
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foreach ($storedhandlers as $handler) {
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$cachedhandlers[$handler->eventname] = array (
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'id' => $handler->id,
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'handlerfile' => $handler->handlerfile,
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'handlerfunction' => $handler->handlerfunction,
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'schedule' => $handler->schedule,
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'internal' => $handler->internal);
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}
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}
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return $cachedhandlers;
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}
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/**
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* Updates all of the event definitions within the database.
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*
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* Unfortunately this isn't as simple as removing them all and then readding
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* the updated event definitions. Chances are queued items are referencing the
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* existing definitions.
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*
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* Note that the absence of the db/events.php event definition file
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* will cause any queued events for the component to be removed from
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* the database.
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*
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* @category event
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* @param string $component examples: 'moodle', 'mod_forum', 'block_quiz_results'
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* @return boolean always returns true
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*/
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function events_update_definition($component='moodle') {
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global $DB;
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// load event definition from events.php
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$filehandlers = events_load_def($component);
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// load event definitions from db tables
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// if we detect an event being already stored, we discard from this array later
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// the remaining needs to be removed
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$cachedhandlers = events_get_cached($component);
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foreach ($filehandlers as $eventname => $filehandler) {
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if (!empty($cachedhandlers[$eventname])) {
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if ($cachedhandlers[$eventname]['handlerfile'] === $filehandler['handlerfile'] &&
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$cachedhandlers[$eventname]['handlerfunction'] === serialize($filehandler['handlerfunction']) &&
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$cachedhandlers[$eventname]['schedule'] === $filehandler['schedule'] &&
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$cachedhandlers[$eventname]['internal'] == $filehandler['internal']) {
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// exact same event handler already present in db, ignore this entry
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unset($cachedhandlers[$eventname]);
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continue;
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} else {
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// same event name matches, this event has been updated, update the datebase
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$handler = new stdClass();
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$handler->id = $cachedhandlers[$eventname]['id'];
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$handler->handlerfile = $filehandler['handlerfile'];
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$handler->handlerfunction = serialize($filehandler['handlerfunction']); // static class methods stored as array
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$handler->schedule = $filehandler['schedule'];
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$handler->internal = $filehandler['internal'];
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$DB->update_record('events_handlers', $handler);
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unset($cachedhandlers[$eventname]);
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continue;
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}
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} else {
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// if we are here, this event handler is not present in db (new)
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// add it
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$handler = new stdClass();
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$handler->eventname = $eventname;
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$handler->component = $component;
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$handler->handlerfile = $filehandler['handlerfile'];
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$handler->handlerfunction = serialize($filehandler['handlerfunction']); // static class methods stored as array
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$handler->schedule = $filehandler['schedule'];
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$handler->status = 0;
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$handler->internal = $filehandler['internal'];
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$DB->insert_record('events_handlers', $handler);
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}
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}
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// clean up the left overs, the entries in cached events array at this points are deprecated event handlers
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// and should be removed, delete from db
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events_cleanup($component, $cachedhandlers);
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events_get_handlers('reset');
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return true;
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}
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/**
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* Remove all event handlers and queued events
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*
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* @category event
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* @param string $component examples: 'moodle', 'mod_forum', 'block_quiz_results'
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*/
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function events_uninstall($component) {
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$cachedhandlers = events_get_cached($component);
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events_cleanup($component, $cachedhandlers);
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events_get_handlers('reset');
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}
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/**
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* Deletes cached events that are no longer needed by the component.
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*
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* @access protected To be used from eventslib only
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*
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* @param string $component examples: 'moodle', 'mod_forum', 'block_quiz_results'
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* @param array $cachedhandlers array of the cached events definitions that will be
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* @return int number of unused handlers that have been removed
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*/
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function events_cleanup($component, $cachedhandlers) {
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global $DB;
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$deletecount = 0;
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foreach ($cachedhandlers as $eventname => $cachedhandler) {
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if ($qhandlers = $DB->get_records('events_queue_handlers', array('handlerid'=>$cachedhandler['id']))) {
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//debugging("Removing pending events from queue before deleting of event handler: $component - $eventname");
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foreach ($qhandlers as $qhandler) {
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events_dequeue($qhandler);
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}
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}
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$DB->delete_records('events_handlers', array('eventname'=>$eventname, 'component'=>$component));
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$deletecount++;
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}
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return $deletecount;
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}
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/****************** End of Events handler Definition code *******************/
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/**
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* Puts a handler on queue
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*
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* @access protected To be used from eventslib only
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*
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* @param stdClass $handler event handler object from db
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* @param stdClass $event event data object
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* @param string $errormessage The error message indicating the problem
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* @return int id number of new queue handler
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*/
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function events_queue_handler($handler, $event, $errormessage) {
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global $DB;
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if ($qhandler = $DB->get_record('events_queue_handlers', array('queuedeventid'=>$event->id, 'handlerid'=>$handler->id))) {
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debugging("Please check code: Event id $event->id is already queued in handler id $qhandler->id");
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return $qhandler->id;
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}
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// make a new queue handler
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$qhandler = new stdClass();
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$qhandler->queuedeventid = $event->id;
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$qhandler->handlerid = $handler->id;
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$qhandler->errormessage = $errormessage;
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$qhandler->timemodified = time();
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if ($handler->schedule === 'instant' and $handler->status == 1) {
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$qhandler->status = 1; //already one failed attempt to dispatch this event
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} else {
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$qhandler->status = 0;
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}
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return $DB->insert_record('events_queue_handlers', $qhandler);
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}
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/**
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* trigger a single event with a specified handler
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*
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* @access protected To be used from eventslib only
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*
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* @param stdClass $handler This shoudl be a row from the events_handlers table.
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* @param stdClass $eventdata An object containing information about the event
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* @param string $errormessage error message indicating problem
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* @return bool|null True means event processed, false means retry event later; may throw exception, NULL means internal error
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*/
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function events_dispatch($handler, $eventdata, &$errormessage) {
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global $CFG;
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$function = unserialize($handler->handlerfunction);
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if (is_callable($function)) {
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// oki, no need for includes
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} else if (file_exists($CFG->dirroot.$handler->handlerfile)) {
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include_once($CFG->dirroot.$handler->handlerfile);
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} else {
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$errormessage = "Handler file of component $handler->component: $handler->handlerfile can not be found!";
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return null;
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}
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// checks for handler validity
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if (is_callable($function)) {
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$result = call_user_func($function, $eventdata);
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if ($result === false) {
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$errormessage = "Handler function of component $handler->component: $handler->handlerfunction requested resending of event!";
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return false;
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}
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return true;
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} else {
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$errormessage = "Handler function of component $handler->component: $handler->handlerfunction not callable function or class method!";
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return null;
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}
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}
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/**
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* given a queued handler, call the respective event handler to process the event
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*
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* @access protected To be used from eventslib only
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*
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* @param stdClass $qhandler events_queued_handler row from db
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* @return boolean true means event processed, false means retry later, NULL means fatal failure
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*/
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function events_process_queued_handler($qhandler) {
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global $DB;
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// get handler
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if (!$handler = $DB->get_record('events_handlers', array('id'=>$qhandler->handlerid))) {
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debugging("Error processing queue handler $qhandler->id, missing handler id: $qhandler->handlerid");
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//irrecoverable error, remove broken queue handler
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events_dequeue($qhandler);
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return NULL;
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}
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// get event object
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if (!$event = $DB->get_record('events_queue', array('id'=>$qhandler->queuedeventid))) {
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// can't proceed with no event object - might happen when two crons running at the same time
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debugging("Error processing queue handler $qhandler->id, missing event id: $qhandler->queuedeventid");
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//irrecoverable error, remove broken queue handler
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events_dequeue($qhandler);
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return NULL;
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}
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// call the function specified by the handler
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try {
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$errormessage = 'Unknown error';
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if (events_dispatch($handler, unserialize(base64_decode($event->eventdata)), $errormessage)) {
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//everything ok
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events_dequeue($qhandler);
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return true;
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}
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} catch (Exception $e) {
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// the problem here is that we do not want one broken handler to stop all others,
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// cron handlers are very tricky because the needed data might have been deleted before the cron execution
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$errormessage = "Handler function of component $handler->component: $handler->handlerfunction threw exception :" .
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$e->getMessage() . "\n" . format_backtrace($e->getTrace(), true);
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if (!empty($e->debuginfo)) {
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$errormessage .= $e->debuginfo;
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}
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}
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//dispatching failed
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$qh = new stdClass();
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$qh->id = $qhandler->id;
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$qh->errormessage = $errormessage;
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$qh->timemodified = time();
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$qh->status = $qhandler->status + 1;
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$DB->update_record('events_queue_handlers', $qh);
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debugging($errormessage);
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return false;
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}
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/**
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* Removes this queued handler from the events_queued_handler table
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*
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* Removes events_queue record from events_queue if no more references to this event object exists
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*
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* @access protected To be used from eventslib only
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*
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* @param stdClass $qhandler A row from the events_queued_handler table
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*/
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function events_dequeue($qhandler) {
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global $DB;
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// first delete the queue handler
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$DB->delete_records('events_queue_handlers', array('id'=>$qhandler->id));
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// if no more queued handler is pointing to the same event - delete the event too
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if (!$DB->record_exists('events_queue_handlers', array('queuedeventid'=>$qhandler->queuedeventid))) {
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$DB->delete_records('events_queue', array('id'=>$qhandler->queuedeventid));
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}
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}
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/**
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* Returns handlers for given event. Uses caching for better perf.
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*
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* @access protected To be used from eventslib only
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*
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* @staticvar array $handlers
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* @param string $eventname name of event or 'reset'
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* @return array|false array of handlers or false otherwise
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*/
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function events_get_handlers($eventname) {
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global $DB;
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static $handlers = array();
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if ($eventname === 'reset') {
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$handlers = array();
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return false;
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}
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if (!array_key_exists($eventname, $handlers)) {
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$handlers[$eventname] = $DB->get_records('events_handlers', array('eventname'=>$eventname));
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}
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return $handlers[$eventname];
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}
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/**
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* Events cron will try to empty the events queue by processing all the queued events handlers
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*
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* @access public Part of the public API
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* @category event
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* @param string $eventname empty means all
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* @return int number of dispatched events
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*/
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function events_cron($eventname='') {
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global $DB;
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$failed = array();
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$processed = 0;
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if ($eventname) {
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$sql = "SELECT qh.*
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FROM {events_queue_handlers} qh, {events_handlers} h
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WHERE qh.handlerid = h.id AND h.eventname=?
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ORDER BY qh.id";
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$params = array($eventname);
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} else {
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$sql = "SELECT *
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FROM {events_queue_handlers}
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ORDER BY id";
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$params = array();
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}
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$rs = $DB->get_recordset_sql($sql, $params);
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foreach ($rs as $qhandler) {
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if (isset($failed[$qhandler->handlerid])) {
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// do not try to dispatch any later events when one already asked for retry or ended with exception
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continue;
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}
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$status = events_process_queued_handler($qhandler);
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if ($status === false) {
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// handler is asking for retry, do not send other events to this handler now
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$failed[$qhandler->handlerid] = $qhandler->handlerid;
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} else if ($status === NULL) {
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// means completely broken handler, event data was purged
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$failed[$qhandler->handlerid] = $qhandler->handlerid;
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} else {
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$processed++;
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}
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}
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$rs->close();
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// remove events that do not have any handlers waiting
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$sql = "SELECT eq.id
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FROM {events_queue} eq
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LEFT JOIN {events_queue_handlers} qh ON qh.queuedeventid = eq.id
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WHERE qh.id IS NULL";
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$rs = $DB->get_recordset_sql($sql);
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foreach ($rs as $event) {
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//debugging('Purging stale event '.$event->id);
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$DB->delete_records('events_queue', array('id'=>$event->id));
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}
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$rs->close();
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return $processed;
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}
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/**
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* Do not call directly, this is intended to be used from new event base only.
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*
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* @private
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* @param string $eventname name of the event
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* @param mixed $eventdata event data object
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* @return int number of failed events
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*/
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function events_trigger_legacy($eventname, $eventdata) {
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global $CFG, $USER, $DB;
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$failedcount = 0; // number of failed events.
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// pull out all registered event handlers
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if ($handlers = events_get_handlers($eventname)) {
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foreach ($handlers as $handler) {
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$errormessage = '';
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if ($handler->schedule === 'instant') {
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if ($handler->status) {
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//check if previous pending events processed
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if (!$DB->record_exists('events_queue_handlers', array('handlerid'=>$handler->id))) {
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// ok, queue is empty, lets reset the status back to 0 == ok
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$handler->status = 0;
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$DB->set_field('events_handlers', 'status', 0, array('id'=>$handler->id));
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// reset static handler cache
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events_get_handlers('reset');
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}
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}
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// dispatch the event only if instant schedule and status ok
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if ($handler->status or (!$handler->internal and $DB->is_transaction_started())) {
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// increment the error status counter
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$handler->status++;
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$DB->set_field('events_handlers', 'status', $handler->status, array('id'=>$handler->id));
|
|
// reset static handler cache
|
|
events_get_handlers('reset');
|
|
|
|
} else {
|
|
$errormessage = 'Unknown error';
|
|
$result = events_dispatch($handler, $eventdata, $errormessage);
|
|
if ($result === true) {
|
|
// everything is fine - event dispatched
|
|
continue;
|
|
} else if ($result === false) {
|
|
// retry later - set error count to 1 == send next instant into cron queue
|
|
$DB->set_field('events_handlers', 'status', 1, array('id'=>$handler->id));
|
|
// reset static handler cache
|
|
events_get_handlers('reset');
|
|
} else {
|
|
// internal problem - ignore the event completely
|
|
$failedcount ++;
|
|
continue;
|
|
}
|
|
}
|
|
|
|
// update the failed counter
|
|
$failedcount ++;
|
|
|
|
} else if ($handler->schedule === 'cron') {
|
|
//ok - use queueing of events only
|
|
|
|
} else {
|
|
// unknown schedule - ignore event completely
|
|
debugging("Unknown handler schedule type: $handler->schedule");
|
|
$failedcount ++;
|
|
continue;
|
|
}
|
|
|
|
// if even type is not instant, or dispatch asked for retry, queue it
|
|
$event = new stdClass();
|
|
$event->userid = $USER->id;
|
|
$event->eventdata = base64_encode(serialize($eventdata));
|
|
$event->timecreated = time();
|
|
if (debugging()) {
|
|
$dump = '';
|
|
$callers = debug_backtrace();
|
|
foreach ($callers as $caller) {
|
|
if (!isset($caller['line'])) {
|
|
$caller['line'] = '?';
|
|
}
|
|
if (!isset($caller['file'])) {
|
|
$caller['file'] = '?';
|
|
}
|
|
$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 = $dump;
|
|
} else {
|
|
$event->stackdump = '';
|
|
}
|
|
$event->id = $DB->insert_record('events_queue', $event);
|
|
events_queue_handler($handler, $event, $errormessage);
|
|
}
|
|
} else {
|
|
// No handler found for this event name - this is ok!
|
|
}
|
|
|
|
return $failedcount;
|
|
}
|
|
|
|
/**
|
|
* checks if an event is registered for this component
|
|
*
|
|
* @access public Part of the public API
|
|
*
|
|
* @param string $eventname name of the event
|
|
* @param string $component component name, can be mod/data or moodle
|
|
* @return bool
|
|
*/
|
|
function events_is_registered($eventname, $component) {
|
|
global $DB;
|
|
return $DB->record_exists('events_handlers', array('component'=>$component, 'eventname'=>$eventname));
|
|
}
|
|
|
|
/**
|
|
* checks if an event is queued for processing - either cron handlers attached or failed instant handlers
|
|
*
|
|
* @access public Part of the public API
|
|
*
|
|
* @param string $eventname name of the event
|
|
* @return int number of queued events
|
|
*/
|
|
function events_pending_count($eventname) {
|
|
global $DB;
|
|
|
|
$sql = "SELECT COUNT('x')
|
|
FROM {events_queue_handlers} qh
|
|
JOIN {events_handlers} h ON h.id = qh.handlerid
|
|
WHERE h.eventname = ?";
|
|
|
|
return $DB->count_records_sql($sql, array($eventname));
|
|
}
|