Proyectos de Subversion Moodle

<?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 <dmitriim@catalyst-au.net>

 * @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) {

        // We should use get_course() instead of get_fast_modinfo() for better performance.

        $course = get_course($key);

        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;

    }

}