trace.php

<?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/>.

/**
 * Tracking pixel endpoint.
 *
 * @package    local_bbcomailing
 * @copyright  2026 David Herney @ BambuCo
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */

// Require_login is not needed here.
// phpcs:disable moodle.Files.RequireLogin.Missing
require_once('../../config.php');
require_once($CFG->libdir . '/filelib.php');

$code = required_param('code', PARAM_ALPHANUMEXT);

$record = $DB->get_record('local_bbcomailing_send', ['code' => $code], 'id, viewtime');

if ($record && empty($record->viewtime)) {
    $DB->set_field('local_bbcomailing_send', 'viewtime', time(), ['id' => $record->id]);
}

// Always return a 1x1 transparent pixel PNG.
$img = $CFG->dirroot . '/local/bbcomailing/pix/trace.png';
send_file($img, 'trace.png', null, 0, false, false, 'image/png');
exit;