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See Release Notes

  • Bug fixes for general core bugs in 4.2.x will end 22 April 2024 (12 months).
  • Bug fixes for security issues in 4.2.x will end 7 October 2024 (18 months).
  • PHP version: minimum PHP 8.0.0 Note: minimum PHP version has increased since Moodle 4.1. PHP 8.1.x is supported too.
<?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/>.

/**
 * Classes for converting files between different file formats.
 *
 * @package    core_files
 * @copyright  2017 Andrew Nicols <andrew@nicols.co.uk>
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */
namespace core_files;

defined('MOODLE_INTERNAL') || die();

use stored_file;

/**
 * Class representing a conversion currently in progress.
 *
 * @package    core_files
 * @copyright  2017 Andrew Nicols <andrew@nicols.co.uk>
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */
class conversion extends \core\persistent {

    /**
     * Status value representing a conversion waiting to start.
     */
    const STATUS_PENDING = 0;

    /**
     * Status value representing a conversion in progress.
     */
    const STATUS_IN_PROGRESS = 1;

    /**
     * Status value representing a successful conversion.
     */
    const STATUS_COMPLETE = 2;

    /**
     * Status value representing a failed conversion.
     */
    const STATUS_FAILED = -1;

    /**
     * Table name for this persistent.
     */
    const TABLE = 'file_conversion';

    /**
     * Define properties.
     *
     * @return array
     */
    protected static function define_properties() {
        return array(
            'sourcefileid' => [
                'type' => PARAM_INT,
            ],
            'targetformat' => [
                'type' => PARAM_ALPHANUMEXT,
            ],
            'status' => [
                'type' => PARAM_INT,
                'choices' => [
                    self::STATUS_PENDING,
                    self::STATUS_IN_PROGRESS,
                    self::STATUS_COMPLETE,
                    self::STATUS_FAILED,
                ],
                'default' => self::STATUS_PENDING,
            ],
            'statusmessage' => [
                'type' => PARAM_RAW,
                'null' => NULL_ALLOWED,
                'default' => null,
            ],
            'converter' => [
                'type' => PARAM_RAW,
                'null' => NULL_ALLOWED,
                'default' => null,
            ],
            'destfileid' => [
                'type' => PARAM_INT,
                'null' => NULL_ALLOWED,
                'default' => null,
            ],
            'data' => [
                'type' => PARAM_RAW,
                'null' => NULL_ALLOWED,
                'default' => null,
            ],
        );
    }

    /**
     * Fetch all conversions relating to the specified file.
     *
     * Only conversions which have a valid file are returned.
     *
     * @param   stored_file $file The source file being converted
     * @param   string $format The targetforamt to filter to
     * @return  conversion[]
     */
    public static function get_conversions_for_file(stored_file $file, $format) {
        global $DB;
        $instances = [];

        // Conversion records are intended for tracking a conversion in progress or recently completed.
        // The record is removed periodically, but the destination file is not.
        // We need to fetch all conversion records which match the source file and target, and also all source and
        // destination files which do not have a conversion record.
        $sqlfields = self::get_sql_fields('c', 'conversion');

        // Fetch actual conversions which relate to the specified source file, and have a matching conversion record,
        // and either have a valid destination file which still exists, or do not have a destination file at all.
        $sql = "SELECT {$sqlfields}
                FROM {" . self::TABLE . "} c
< INNER JOIN {files} conversionsourcefile ON conversionsourcefile.id = c.sourcefileid
> JOIN {files} conversionsourcefile ON conversionsourcefile.id = c.sourcefileid
LEFT JOIN {files} conversiondestfile ON conversiondestfile.id = c.destfileid
< WHERE < conversionsourcefile.contenthash = :ccontenthash
> WHERE conversionsourcefile.contenthash = :ccontenthash
AND c.targetformat = :cformat
< AND ( < c.destfileid IS NULL OR conversiondestfile.id IS NOT NULL < )";
> AND (c.destfileid IS NULL OR conversiondestfile.id IS NOT NULL)";
// Fetch a empty conversion record for each source/destination combination that we find to match where the // destination file is in the correct filearea/filepath/filename combination to meet the requirements. // This ensures that existing conversions are used where possible, even if there is no 'conversion' record for // them. $sql .= " UNION ALL SELECT NULL AS conversionid, orphanedsourcefile.id AS conversionsourcefileid, :oformat AS conversiontargetformat, 2 AS conversionstatus, NULL AS conversionstatusmessage, NULL AS conversionconverter, orphaneddestfile.id AS conversiondestfileid, NULL AS conversiondata, 0 AS conversiontimecreated, 0 AS conversiontimemodified, 0 AS conversionusermodified FROM {files} orphanedsourcefile INNER JOIN {files} orphaneddestfile ON ( orphaneddestfile.filename = orphanedsourcefile.contenthash AND orphaneddestfile.component = 'core' AND orphaneddestfile.filearea = 'documentconversion' AND orphaneddestfile.filepath = :ofilepath ) LEFT JOIN {" . self::TABLE . "} orphanedconversion ON orphanedconversion.destfileid = orphaneddestfile.id WHERE orphanedconversion.id IS NULL AND orphanedsourcefile.id = :osourcefileid "; $records = $DB->get_records_sql($sql, [ 'ccontenthash' => $file->get_contenthash(), 'osourcefileid' => $file->get_id(),
< 'cfilepath' => "/{$format}/",
'ofilepath' => "/{$format}/", 'cformat' => $format, 'oformat' => $format, ]); foreach ($records as $record) { $data = self::extract_record($record, 'conversion'); $newrecord = new static(0, $data); $instances[] = $newrecord; } return $instances; } /** * Remove all old conversion records. */ public static function remove_old_conversion_records() { global $DB; $DB->delete_records_select(self::TABLE, 'timemodified <= :weekagosecs', [ 'weekagosecs' => time() - WEEKSECS, ]); } /** * Remove orphan records. * * Records are considered orphans when their source file not longer exists. * In this scenario we do not want to keep the converted file any longer, * in particular to be compliant with privacy laws. */ public static function remove_orphan_records() { global $DB; $sql = " SELECT c.id FROM {" . self::TABLE . "} c LEFT JOIN {files} f ON f.id = c.sourcefileid WHERE f.id IS NULL"; $ids = $DB->get_fieldset_sql($sql, []); if (empty($ids)) { return; } list($insql, $inparams) = $DB->get_in_or_equal($ids, SQL_PARAMS_NAMED); $DB->delete_records_select(self::TABLE, "id $insql", $inparams); } /** * Set the source file id for the conversion. * * @param stored_file $file The file to convert * @return $this */ public function set_sourcefile(stored_file $file) { $this->raw_set('sourcefileid', $file->get_id()); return $this; } /** * Fetch the source file. * * @return stored_file|false The source file */ public function get_sourcefile() { $fs = get_file_storage(); return $fs->get_file_by_id($this->get('sourcefileid')); } /** * Set the destination file for this conversion. * * @param string $filepath The path to the converted file * @return $this */ public function store_destfile_from_path($filepath) { if ($record = $this->get_file_record()) { $fs = get_file_storage(); $existing = $fs->get_file( $record['contextid'], $record['component'], $record['filearea'], $record['itemid'], $record['filepath'], $record['filename'] ); if ($existing) { $existing->delete(); } $file = $fs->create_file_from_pathname($record, $filepath); $this->raw_set('destfileid', $file->get_id()); } return $this; } /** * Set the destination file for this conversion. * * @param string $content The content of the converted file * @return $this */ public function store_destfile_from_string($content) { if ($record = $this->get_file_record()) { $fs = get_file_storage(); $existing = $fs->get_file( $record['contextid'], $record['component'], $record['filearea'], $record['itemid'], $record['filepath'], $record['filename'] ); if ($existing) { $existing->delete(); } $file = $fs->create_file_from_string($record, $content); $this->raw_set('destfileid', $file->get_id()); } return $this; } /** * Get the destination file. * * @return stored_file|bool Destination file */ public function get_destfile() { $fs = get_file_storage(); return $fs->get_file_by_id($this->get('destfileid')); } /** * Helper to ensure that the returned status is always an int. * * @return int status */ protected function get_status() { return (int) $this->raw_get('status'); } /** * Get an instance of the current converter. * * @return converter_interface|false current converter instance */ public function get_converter_instance() { $currentconverter = $this->get('converter'); if ($currentconverter && class_exists($currentconverter)) { return new $currentconverter(); } else { return false; } } /** * Transform data into a storable format. * * @param \stdClass $data The data to be stored * @return $this */ protected function set_data($data) { $this->raw_set('data', json_encode($data)); return $this; } /** * Transform data into a storable format. * * @return \stdClass The stored data */ protected function get_data() { $data = $this->raw_get('data'); if (!empty($data)) { return json_decode($data); } return (object) []; } /** * Return the file record base for use in the files table. * * @return array|bool */ protected function get_file_record() { $file = $this->get_sourcefile(); if (!$file) { // If the source file was removed before we completed, we must return early. return false; } return [ 'contextid' => \context_system::instance()->id, 'component' => 'core', 'filearea' => 'documentconversion', 'itemid' => 0, 'filepath' => "/" . $this->get('targetformat') . "/", 'filename' => $file->get_contenthash(), ]; } }