MDL-66667 course: add course image cache

2021-03-15 12:50:35 +11:00
parent fc335f5ea0
commit 2affc87d2b
8 changed files with 371 additions and 15 deletions
@@ -0,0 +1,102 @@
+<?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 core_course\cache;
+
+use cache_data_source;
+use cache_definition;
+use moodle_url;
+use core_course_list_element;
+
+/**
+ * Class to describe cache data source for course image.
+ *
+ * @package    core
+ * @subpackage course
+ * @author     Dmitrii Metelkin <[email protected]>
+ * @copyright  2021 Catalyst IT
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class course_image implements cache_data_source {
+
+    /** @var course_image */
+    protected static $instance = null;
+
+    /**
+     * Returns an instance of the data source class that the cache can use for loading data using the other methods
+     * specified by this interface.
+     *
+     * @param cache_definition $definition
+     * @return \core_course\cache\course_image
+     */
+    public static function get_instance_for_cache(cache_definition $definition): course_image {
+        if (is_null(self::$instance)) {
+            self::$instance = new course_image();
+        }
+        return self::$instance;
+    }
+
+    /**
+     * Loads the data for the key provided ready formatted for caching.
+     *
+     * @param string|int $key The key to load.
+     * @return string|bool Returns course image url as a string or false if the image is not exist
+     */
+    public function load_for_cache($key) {
+        $course = get_fast_modinfo($key)->get_course();
+        return $this->get_image_url_from_overview_files($course);
+    }
+
+    /**
+     * Returns image URL from course overview files.
+     *
+     * @param \stdClass $course Course object.
+     * @return null|string Image URL or null if it's not exists.
+     */
+    protected function get_image_url_from_overview_files(\stdClass $course): ?string {
+        $courseinlist = new core_course_list_element($course);
+        foreach ($courseinlist->get_course_overviewfiles() as $file) {
+            if ($file->is_valid_image()) {
+                return moodle_url::make_pluginfile_url(
+                    $file->get_contextid(),
+                    $file->get_component(),
+                    $file->get_filearea(),
+                    null,
+                    $file->get_filepath(),
+                    $file->get_filename()
+                )->out();
+            }
+        }
+
+        // Returning null if no image found to let it be cached
+        // as false is what cache API returns then a data is not found in cache.
+        return null;
+    }
+
+    /**
+     * Loads several keys for the cache.
+     *
+     * @param array $keys An array of keys each of which will be string|int.
+     * @return array An array of matching data items.
+     */
+    public function load_many_for_cache(array $keys): array {
+        $records = [];
+        foreach ($keys as $key) {
+            $records[$key] = $this->load_for_cache($key);
+        }
+        return $records;
+    }
+}