chamilo-lms2/main/survey/link.php

<?php
/* For licensing terms, see /license.txt */

require_once '../inc/global.inc.php';

$survey_id = isset($_REQUEST['i']) ? intval($_REQUEST['i']) : null;

if (empty($survey_id)) {
    api_not_allowed(true);
}
if (!SurveyManager::survey_generation_hash_available()) {
    api_not_allowed(true);
}
$course_info  = api_get_course_info_by_id($_REQUEST['c']);

$hash_is_valid = SurveyManager::validate_survey_hash(
    $survey_id,
    $_REQUEST['c'],
    $_REQUEST['s'],
    $_REQUEST['g'],
    $_REQUEST['h']
);
if ($hash_is_valid && $course_info) {
    $survey_data = SurveyManager::get_survey(
        $survey_id,
        null,
        $course_info['code']
    );

    $invitation_code = api_get_unique_id();

    $params = array(
            'c_id' => $_REQUEST['c'],
            'session_id' => $_REQUEST['s'],
            'user' => $invitation_code,
            'survey_code' => $survey_data['code'],
            'invitation_code' => $invitation_code,
            'invitation_date' => api_get_utc_datetime()
    );
    $invitation_id = SurveyUtil::save_invitation($params);

    if ($invitation_id) {
        $link = api_get_path(WEB_CODE_PATH).'survey/fillsurvey.php?invitationcode='.$invitation_code.'&course='.$course_info['code'];
        header('Location: '.$link);
        exit;
    }
} else {
    api_not_allowed(true);
}