MBS-8702: Improve caching (#93)

amd/src/placestore.js

@@ -1,5 +1,5 @@
 let placestore = {
-    version: 2024012601,
+    version: 2024022102,
     id: 0,
     places: [],
     paths: [],
@@ -36,7 +36,7 @@ let placestore = {
             // eslint-disable-next-line no-empty
         } catch { }
         // Update version (only relevant if learning map is saved)
-        this.version = 2024012601;
+        this.version = 2024022102;
     },
     /**
      * Returns placestore as a JSON string ()

backup/moodle2/backup_learningmap_stepslib.php

@@ -32,7 +32,7 @@ protected function define_structure(): backup_nested_element {
         $learningmap = new backup_nested_element(
             'learningmap',
             ['id'],
-            ['course', 'name', 'intro', 'introformat', 'timemodified', 'placestore', 'completiontype']
+            ['course', 'name', 'intro', 'introformat', 'timemodified', 'placestore', 'completiontype', 'backlink']
         );
 
         $learningmap->set_source_table('learningmap', ['id' => backup::VAR_ACTIVITYID]);

backup/moodle2/restore_learningmap_activity_task.class.php

@@ -102,8 +102,8 @@ public function after_restore(): void {
         $item->intro = str_replace('learningmap-svgmap-' . $oldmapid, 'learningmap-svgmap-' . $newmapid, $item->intro);
         $placestore->mapid = $newmapid;
 
-        if (!isset($placestore->version) || $placestore->version < 2024012601) {
-            $placestore->version = 2024012601;
+        if (!isset($placestore->version) || $placestore->version < 2024022102) {
+            $placestore->version = 2024022102;
             // Needs 1 as default value (otherwise all place strokes would be hidden).
             if (!isset($placestore->strokeopacity)) {
                 $placestore->strokeopacity = 1;

classes/autoupdate.php

@@ -73,6 +73,7 @@ public static function update_from_event(\core\event\base $event): void {
      */
     public static function update_from_delete_event(\core\event\base $event): void {
         global $DB;
+
         $data = $event->get_data();
         if (isset($data['courseid']) && $data['courseid'] > 0) {
             $modinfo = get_fast_modinfo($data['courseid']);
@@ -85,6 +86,7 @@ public static function update_from_delete_event(\core\event\base $event): void {
                         foreach ($placestore->places as $p) {
                             if ($p->linkedActivity == $data['objectid']) {
                                 $p->linkedActivity = null;
+                                cachemanager::remove_cmid($data['objectid']);
                                 $changed = true;
                             }
                         }
@@ -95,23 +97,28 @@ public static function update_from_delete_event(\core\event\base $event): void {
                 }
             }
         }
-        self::reset_backlink_cache($event);
+
+        // If the course module was a learningmap, reset the backlink cache of the whole course.
+        self::reset_backlink_cache_if_necessary($event);
     }
 
     /**
-     * Resets backlink cache of the whole course if a learningmap was created / updated / deleted.
+     * Resets backlink cache of the whole course if a learningmap was created / updated / deleted or if
+     * the course settings have changed (as course format may have changed).
      * @param \core\event\base $event
-     * @return void
+     * @return bool
      */
-    public static function reset_backlink_cache(\core\event\base $event): void {
+    public static function reset_backlink_cache_if_necessary(\core\event\base $event): bool {
+        $data = $event->get_data();
         if (isset($data['courseid']) && $data['courseid'] > 0) {
-            $course = $data['courseid'];
-            $cache = \cache::make('mod_learningmap', 'backlinks');
-            $modinfo = get_fast_modinfo($course);
-            $cms = $modinfo->get_cms();
-            foreach ($cms as $cm) {
-                $cache->delete($cm->id);
+            if (
+                ($data['objecttable'] == 'course' && in_array('format', $data['other']['updatedfields'])) ||
+                ($data['objecttable'] == 'course_modules' && $data['other']['modulename'] == 'learningmap')
+            ) {
+                cachemanager::reset_backlink_cache($data['courseid']);
+                return true;
             }
         }
+        return false;
     }
 }

classes/cachemanager.php

@@ -0,0 +1,113 @@
+<?php
+// This file is part of Moodle - https://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <https://www.gnu.org/licenses/>.
+
+namespace mod_learningmap;
+
+/**
+ * Cache manager class for mod_learningmap
+ *
+ * @package     mod_learningmap
+ * @copyright   2021-2024, ISB Bayern
+ * @author      Stefan Hanauska <[email protected]>
+ * @license     http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class cachemanager {
+    /**
+     * Reset the backlink cache for a course (includes rebuilding it) or the whole instance (if $courseid is 0).
+     *
+     * @param int $courseid The id of the course (defaults to 0).
+     * @return void
+     */
+    public static function reset_backlink_cache(int $courseid = 0): void {
+        if (get_config('mod_learningmap', 'backlinkallowed') == 0) {
+            return;
+        }
+
+        $cache = \cache::make('mod_learningmap', 'backlinks');
+
+        if (empty($courseid)) {
+            // This also deletes the cache key 'fillstate', so the whole cache is invalidated.
+            $cache->purge();
+        } else {
+            $modinfo = get_fast_modinfo($courseid);
+            $cms = $modinfo->get_cms();
+            $cache->delete_many(array_keys($cms));
+        }
+        self::build_backlink_cache($courseid);
+    }
+
+    /**
+     * Builds the backlink cache for a course or for the whole instance (e.g. after purging the cache).
+     * Building the cache for a course should only be used as a fallback if the cache is not filled for the whole instance.
+     *
+     * @param int $courseid Id of the course, if 0 the cache will be built for the whole instance.
+     * @return void
+     */
+    public static function build_backlink_cache(int $courseid = 0) {
+        global $DB;
+
+        if (get_config('mod_learningmap', 'backlinkallowed') == 0) {
+            return;
+        }
+
+        $backlinks = [];
+        $cache = \cache::make('mod_learningmap', 'backlinks');
+
+        $conditions = ['backlink' => 1];
+        if (!empty($courseid)) {
+            $conditions['course'] = $courseid;
+        }
+
+        $records = $DB->get_recordset('learningmap', $conditions, '', 'id, placestore, backlink, course');
+        foreach ($records as $record) {
+            $modinfo = get_fast_modinfo($record->course);
+            $module = $modinfo->instances['learningmap'][$record->id];
+            $placestore = json_decode($record->placestore);
+            $coursepageurl = course_get_format($module->course)->get_view_url($module->sectionnum);
+            $coursepageurl->set_anchor('module-' . $module->id);
+            foreach ($placestore->places as $place) {
+                $url = !empty($module->showdescription) ?
+                    $coursepageurl->out() :
+                    new \moodle_url('/mod/learningmap/view.php', ['id' => $module->id]);
+                $backlinks[$place->linkedActivity][$module->id] = [
+                    'url' => $url,
+                    'name' => $module->name,
+                    'cmid' => $module->id,
+                ];
+            }
+        }
+
+        foreach ($backlinks as $cmid => $backlink) {
+            $cache->set($cmid, $backlink);
+        }
+
+        if (empty($courseid)) {
+            // Finally set the flag to indicate that the cache is properly built.
+            $cache->set('fillstate', time());
+        }
+    }
+
+    /**
+     * Removes a cmid from the backlink cache (e.g. when the course module was deleted).
+     *
+     * @param int $cmid Course module id
+     * @return void
+     */
+    public static function remove_cmid(int $cmid) {
+        $cache = \cache::make('mod_learningmap', 'backlinks');
+        $cache->delete($cmid);
+    }
+}

classes/task/fill_backlink_cache.php

@@ -0,0 +1,61 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+namespace mod_learningmap\task;
+
+use mod_learningmap\cachemanager;
+
+/**
+ * Task to fill backlink cache.
+ *
+ * @package    mod_learningmap
+ * @copyright  2021-2024, ISB Bayern
+ * @author     Stefan Hanauska
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class fill_backlink_cache extends \core\task\scheduled_task {
+    /**
+     * Get a descriptive name for this task (shown to admins).
+     *
+     * @return string
+     */
+    public function get_name() {
+        return get_string('fill_backlink_cache_task', 'mod_learningmap');
+    }
+
+    /**
+     * Fill backlink cache.
+     */
+    public function execute() {
+        if (get_config('mod_learningmap', 'backlinkallowed') == 0) {
+            return;
+        }
+
+        $cache = \cache::make('mod_learningmap', 'backlinks');
+
+        $fillstate = $cache->get('fillstate');
+
+        // If the cache is filled within the last 24 hours, do nothing.
+        if (!empty($fillstate) && $fillstate < time() - 60 * 60 * 24) {
+            mtrace('Backlink cache is already filled within the last 24 hours. Exiting.');
+            return;
+        }
+
+        mtrace('Building backlink cache started...');
+        cachemanager::build_backlink_cache();
+        mtrace('Building backlink cache finished.');
+    }
+}