source: moodle/trunk/fuentes/admin/tool/monitor/classes/eventobservers.php @ 136

Last change on this file since 136 was 136, checked in by mabarracus, 4 years ago

Ported code to xenial

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1<?php
2// This file is part of Moodle - http://moodle.org/
3//
4// Moodle is free software: you can redistribute it and/or modify
5// it under the terms of the GNU General Public License as published by
6// the Free Software Foundation, either version 3 of the License, or
7// (at your option) any later version.
8//
9// Moodle is distributed in the hope that it will be useful,
10// but WITHOUT ANY WARRANTY; without even the implied warranty of
11// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12// GNU General Public License for more details.
13//
14// You should have received a copy of the GNU General Public License
15// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
16
17/**
18 * Observer class containing methods monitoring various events.
19 *
20 * @package    tool_monitor
21 * @copyright  2014 onwards Ankit Agarwal <ankit.agrr@gmail.com>
22 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
23 */
24
25namespace tool_monitor;
26
27defined('MOODLE_INTERNAL') || die();
28
29/**
30 * Observer class containing methods monitoring various events.
31 *
32 * @since      Moodle 2.8
33 * @package    tool_monitor
34 * @copyright  2014 onwards Ankit Agarwal <ankit.agrr@gmail.com>
35 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
36 */
37class eventobservers {
38
39    /** @var array $buffer buffer of events. */
40    protected $buffer = array();
41
42    /** @var int Number of entries in the buffer. */
43    protected $count = 0;
44
45    /** @var  eventobservers a reference to a self instance. */
46    protected static $instance;
47
48    /**
49     * Course delete event observer.
50     * This observer monitors course delete event, and when a course is deleted it deletes any rules and subscriptions associated
51     * with it, so no orphan data is left behind.
52     *
53     * @param \core\event\course_deleted $event The course deleted event.
54     */
55    public static function course_deleted(\core\event\course_deleted $event) {
56        $rules = rule_manager::get_rules_by_courseid($event->courseid, 0, 0, false);
57        foreach ($rules as $rule) {
58            rule_manager::delete_rule($rule->id, $event->get_context());
59        }
60    }
61
62    /**
63     * The observer monitoring all the events.
64     *
65     * This observers puts small event objects in buffer for later writing to the database. At the end of the request the buffer
66     * is cleaned up and all data dumped into the tool_monitor_events table.
67     *
68     * @param \core\event\base $event event object
69     */
70    public static function process_event(\core\event\base $event) {
71        if (!get_config('tool_monitor', 'enablemonitor')) {
72            return; // The tool is disabled. Nothing to do.
73        }
74
75        if (empty(self::$instance)) {
76            self::$instance = new static();
77            // Register shutdown handler - this is useful for buffering, processing events, etc.
78            \core_shutdown_manager::register_function(array(self::$instance, 'process_buffer'));
79        }
80
81        self::$instance->buffer_event($event);
82
83        if (PHPUNIT_TEST) {
84            // Process buffer after every event when unit testing.
85            self::$instance->process_buffer();
86
87        }
88    }
89
90    /**
91     * Api to buffer events to store, to reduce db queries.
92     *
93     * @param \core\event\base $event
94     */
95    protected function buffer_event(\core\event\base $event) {
96
97        // If there are no subscriptions for this event do not buffer it.
98        if (!\tool_monitor\subscription_manager::event_has_subscriptions($event->eventname, $event->courseid)) {
99            return;
100        }
101
102        $eventdata = $event->get_data();
103        $eventobj = new \stdClass();
104        $eventobj->eventname = $eventdata['eventname'];
105        $eventobj->contextid = $eventdata['contextid'];
106        $eventobj->contextlevel = $eventdata['contextlevel'];
107        $eventobj->contextinstanceid = $eventdata['contextinstanceid'];
108        if ($event->get_url()) {
109            // Get link url if exists.
110            $eventobj->link = $event->get_url()->out();
111        } else {
112            $eventobj->link = '';
113        }
114        $eventobj->courseid = $eventdata['courseid'];
115        $eventobj->timecreated = $eventdata['timecreated'];
116
117        $this->buffer[] = $eventobj;
118        $this->count++;
119    }
120
121    /**
122     * This method process all events stored in the buffer.
123     *
124     * This is a multi purpose api. It does the following:-
125     * 1. Write event data to tool_monitor_events
126     * 2. Find out users that need to be notified about rule completion and schedule a task to send them messages.
127     */
128    public function process_buffer() {
129        global $DB;
130
131        $events = $this->flush(); // Flush data.
132
133        $select = "SELECT COUNT(id) FROM {tool_monitor_events} ";
134        $now = time();
135        $messagestosend = array();
136        $allsubids = array();
137
138        // Let us now process the events and check for subscriptions.
139        foreach ($events as $eventobj) {
140            $subscriptions = subscription_manager::get_subscriptions_by_event($eventobj);
141            $idstosend = array();
142            foreach ($subscriptions as $subscription) {
143                $starttime = $now - $subscription->timewindow;
144                $starttime = ($starttime > $subscription->lastnotificationsent) ? $starttime : $subscription->lastnotificationsent;
145                if ($subscription->courseid == 0) {
146                    // Site level subscription. Count all events.
147                    $where = "eventname = :eventname AND timecreated >  :starttime";
148                    $params = array('eventname' => $eventobj->eventname, 'starttime' => $starttime);
149                } else {
150                    // Course level subscription.
151                    if ($subscription->cmid == 0) {
152                        // All modules.
153                        $where = "eventname = :eventname AND courseid = :courseid AND timecreated > :starttime";
154                        $params = array('eventname' => $eventobj->eventname, 'courseid' => $eventobj->courseid,
155                                'starttime' => $starttime);
156                    } else {
157                        // Specific module.
158                        $where = "eventname = :eventname AND courseid = :courseid AND contextinstanceid = :cmid
159                                AND timecreated > :starttime";
160                        $params = array('eventname' => $eventobj->eventname, 'courseid' => $eventobj->courseid,
161                                'cmid' => $eventobj->contextinstanceid, 'starttime' => $starttime);
162
163                    }
164                }
165                $sql = $select . "WHERE " . $where;
166                $count = $DB->count_records_sql($sql, $params);
167                if (!empty($count) && $count >= $subscription->frequency) {
168                    $idstosend[] = $subscription->id;
169
170                    // Trigger a subscription_criteria_met event.
171                    // It's possible that the course has been deleted since the criteria was met, so in that case use
172                    // the system context. Set it here and change later if needed.
173                    $context = \context_system::instance();
174                    // We can't perform if (!empty($subscription->courseid)) below as it uses the magic method
175                    // __get to return the variable, which will always result in being empty.
176                    $courseid = $subscription->courseid;
177                    if (!empty($courseid)) {
178                        if ($coursecontext = \context_course::instance($courseid, IGNORE_MISSING)) {
179                            $context = $coursecontext;
180                        }
181                    }
182
183                    $params = array(
184                        'userid' => $subscription->userid,
185                        'courseid' => $subscription->courseid,
186                        'context' => $context,
187                        'other' => array(
188                            'subscriptionid' => $subscription->id
189                        )
190                    );
191                    $event = \tool_monitor\event\subscription_criteria_met::create($params);
192                    $event->trigger();
193                }
194            }
195            if (!empty($idstosend)) {
196                $messagestosend[] = array('subscriptionids' => $idstosend, 'event' => $eventobj);
197                $allsubids = array_merge($allsubids, $idstosend);
198            }
199        }
200
201        if (!empty($allsubids)) {
202            // Update the last trigger flag.
203            list($sql, $params) = $DB->get_in_or_equal($allsubids, SQL_PARAMS_NAMED);
204            $params['now'] = $now;
205            $sql = "UPDATE {tool_monitor_subscriptions} SET lastnotificationsent = :now WHERE id $sql";
206            $DB->execute($sql, $params);
207        }
208
209        // Schedule a task to send notification.
210        if (!empty($messagestosend)) {
211            $adhocktask = new notification_task();
212            $adhocktask->set_custom_data($messagestosend);
213            $adhocktask->set_component('tool_monitor');
214            \core\task\manager::queue_adhoc_task($adhocktask);
215        }
216    }
217
218    /**
219     * Protected method that flushes the buffer of events and writes them to the database.
220     *
221     * @return array a copy of the events buffer.
222     */
223    protected function flush() {
224        global $DB;
225
226        // Flush the buffer to the db.
227        $events = $this->buffer;
228        $DB->insert_records('tool_monitor_events', $events); // Insert the whole chunk into the database.
229        $this->buffer = array();
230        $this->count = 0;
231        return $events;
232    }
233
234    /**
235     * Observer that monitors user deleted event and delete user subscriptions.
236     *
237     * @param \core\event\user_deleted $event the event object.
238     */
239    public static function user_deleted(\core\event\user_deleted $event) {
240        $userid = $event->objectid;
241        subscription_manager::delete_user_subscriptions($userid);
242    }
243
244    /**
245     * Observer that monitors course module deleted event and delete user subscriptions.
246     *
247     * @param \core\event\course_module_deleted $event the event object.
248     */
249    public static function course_module_deleted(\core\event\course_module_deleted $event) {
250        $cmid = $event->contextinstanceid;
251        subscription_manager::delete_cm_subscriptions($cmid);
252    }
253}
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