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/>.

/**

 * Internal library of functions for module hvp

 *

 * All the hvp specific functions, needed to implement the module

 * logic, should go here. Never include this file from your lib.php!

 *

 * @package    mod_hvp

 * @copyright  2016 Joubel AS <contact@joubel.com>

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

use core\message\message;

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

require_once('autoloader.php');

/**

 * Get array with settings for hvp core

 *

 * @param \context_course|\context_module [$context]

 * @return array Settings

 */

function hvp_get_core_settings($context) {

    global $USER, $CFG;

    $systemcontext = \context_system::instance();

    $basepath = \mod_hvp\view_assets::getsiteroot() . '/';

    // Check permissions and generate ajax paths.

    $ajaxpaths = array();

    $savefreq = false;

    $ajaxpath = "{$basepath}mod/hvp/ajax.php?contextId={$context->instanceid}&token=";

    if ($context->contextlevel == CONTEXT_MODULE && has_capability('mod/hvp:saveresults', $context)) {

        $ajaxpaths['setFinished'] = $ajaxpath . \H5PCore::createToken('result') . '&action=set_finished';

        $ajaxpaths['xAPIResult'] = $ajaxpath . \H5PCore::createToken('xapiresult') . '&action=xapiresult';

    }

    if (has_capability('mod/hvp:savecontentuserdata', $context)) {

        $ajaxpaths['contentUserData'] = $ajaxpath . \H5PCore::createToken('contentuserdata') .

            '&action=contents_user_data&content_id=:contentId&data_type=:dataType&sub_content_id=:subContentId';

        if (get_config('mod_hvp', 'enable_save_content_state')) {

            $savefreq = get_config('mod_hvp', 'content_state_frequency');

        }

    }

    $core = \mod_hvp\framework::instance('core');

    $settings = array(

        'baseUrl' => $basepath,

        'url' => "{$basepath}pluginfile.php/{$context->instanceid}/mod_hvp",

        // NOTE: Separate context from content URL !

        'urlLibraries' => "{$basepath}pluginfile.php/{$systemcontext->id}/mod_hvp/libraries",

        'postUserStatistics' => true,

        'ajax' => $ajaxpaths,

        'saveFreq' => $savefreq,

        'siteUrl' => $CFG->wwwroot,

        'l10n' => array('H5P' => $core->getLocalization()),

        'user' => array(

            'name' => $USER->firstname . ' ' . $USER->lastname,

            'mail' => $USER->email

        ),

        'hubIsEnabled' => get_config('mod_hvp', 'hub_is_enabled') ? true : false,

        'reportingIsEnabled' => true,

        'crossorigin' => isset($CFG->mod_hvp_crossorigin) ? $CFG->mod_hvp_crossorigin : null,

        'crossoriginRegex' => isset($CFG->mod_hvp_crossoriginRegex) ? $CFG->mod_hvp_crossoriginRegex : null,

        'crossoriginCacheBuster' => isset($CFG->mod_hvp_crossoriginCacheBuster) ? $CFG->mod_hvp_crossoriginCacheBuster : null,

        'libraryConfig' => $core->h5pF->getLibraryConfig(),

        'pluginCacheBuster' => hvp_get_cache_buster(),

        'libraryUrl' => $basepath . 'mod/hvp/library/js'

    );

    return $settings;

}

/**

 * Get assets (scripts and styles) for hvp core.

 *

 * @param \context_course|\context_module $context

 * @return array

 */

function hvp_get_core_assets($context) {

    global $PAGE;

    // Get core settings.

    $settings = \hvp_get_core_settings($context);

    $settings['core'] = array(

        'styles' => array(),

        'scripts' => array()

    );

    $settings['loadedJs'] = array();

    $settings['loadedCss'] = array();

    // Make sure files are reloaded for each plugin update.

    $cachebuster = \hvp_get_cache_buster();

    // Use relative URL to support both http and https.

    $liburl = \mod_hvp\view_assets::getsiteroot() . '/mod/hvp/library/';

    $relpath = '/' . preg_replace('/^[^:]+:\/\/[^\/]+\//', '', $liburl);

    // Add core stylesheets.

    foreach (\H5PCore::$styles as $style) {

        $settings['core']['styles'][] = $relpath . $style . $cachebuster;

        $PAGE->requires->css(new moodle_url($liburl . $style . $cachebuster));

    }

    // Add core JavaScript.

    foreach (\H5PCore::$scripts as $script) {

        $settings['core']['scripts'][] = $relpath . $script . $cachebuster;

        $PAGE->requires->js(new moodle_url($liburl . $script . $cachebuster), true);

    }

    return $settings;

}

/**

 * Add required assets for displaying the editor.

 *

 * @param int $id Content being edited. null for creating new content

 * @param string $mformid Id of Moodle form

 *

 * @throws coding_exception

 * @throws moodle_exception

 */

function hvp_add_editor_assets($id = null, $mformid = null) {

    global $PAGE, $CFG, $COURSE;

    // First we need to determine the context for permission handling.

    if ($id) {

        // Use cm context when editing existing content.

        $cm = get_coursemodule_from_instance('hvp', $id);

        $context = \context_module::instance($cm->id);

    } else {

        // Use course context when there's no content, i.e. adding new content.

        $context = \context_course::instance($COURSE->id);

    }

    $settings = \hvp_get_core_assets($context);

    // Use jQuery and styles from core.

    $assets = array(

        'css' => $settings['core']['styles'],

        'js' => $settings['core']['scripts']

    );

    // Use relative URL to support both http and https.

    $url = \mod_hvp\view_assets::getsiteroot() . '/mod/hvp/';

    $url = '/' . preg_replace('/^[^:]+:\/\/[^\/]+\//', '', $url);

    // Make sure files are reloaded for each plugin update.

    $cachebuster = \hvp_get_cache_buster();

    // Add editor styles.

    foreach (H5peditor::$styles as $style) {

        $assets['css'][] = $url . 'editor/' . $style . $cachebuster;

    }

    // Add editor JavaScript.

    foreach (H5peditor::$scripts as $script) {

        // We do not want the creator of the iframe inside the iframe.

        if ($script !== 'scripts/h5peditor-editor.js') {

            $assets['js'][] = $url . 'editor/' . $script . $cachebuster;

        }

    }

    // Add JavaScript with library framework integration (editor part).

    $PAGE->requires->js(new moodle_url('/mod/hvp/editor/scripts/h5peditor-editor.js' . $cachebuster), true);

    $PAGE->requires->js(new moodle_url('/mod/hvp/editor/scripts/h5peditor-init.js' . $cachebuster), true);

    $PAGE->requires->js(new moodle_url('/mod/hvp/editor.js' . $cachebuster), true);

    // Add translations.

    $language = \mod_hvp\framework::get_language();

    $languagescript = "editor/language/{$language}.js";

    if (!file_exists("{$CFG->dirroot}/mod/hvp/{$languagescript}")) {

        $languagescript = 'editor/language/en.js';

    }

    $PAGE->requires->js(new moodle_url('/mod/hvp/' . $languagescript . $cachebuster), true);

    // Add JavaScript settings.

    $root = \mod_hvp\view_assets::getsiteroot();

    $filespathbase = "{$root}/pluginfile.php/{$context->id}/mod_hvp/";

    $contentvalidator = \mod_hvp\framework::instance('contentvalidator');

    $editorajaxtoken = \H5PCore::createToken('editorajax');

    $interface = \mod_hvp\framework::instance('interface');

    $siteuuid = $interface->getOption('site_uuid', null);

    $secret   = $interface->getOption('hub_secret', null);

    $enablecontenthub = !empty($siteuuid) && !empty($secret);

    $settings['editor'] = array(

      'filesPath' => $filespathbase . 'editor',

      'fileIcon' => array(

        'path' => $url . 'editor/images/binary-file.png',

        'width' => 50,

        'height' => 50,

      ),

      'ajaxPath' => "{$url}ajax.php?contextId={$context->id}&token={$editorajaxtoken}&action=",

      'libraryUrl' => $url . 'editor/',

      'copyrightSemantics' => $contentvalidator->getCopyrightSemantics(),

      'metadataSemantics' => $contentvalidator->getMetadataSemantics(),

      'assets' => $assets,

      // @codingStandardsIgnoreLine

      'apiVersion' => H5PCore::$coreApi,

      'language' => $language,

      'formId' => $mformid,

      'hub' => [

        'contentSearchUrl' => \H5PHubEndpoints::createURL(\H5PHubEndpoints::CONTENT) . '/search',

      ],

      'enableContentHub' => $enablecontenthub,

    );

    if ($id !== null) {

        $settings['editor']['nodeVersionId'] = $id;

        // Find cm context.

        $cm      = \get_coursemodule_from_instance('hvp', $id);

        $context = \context_module::instance($cm->id);

        // Override content URL.

        $contenturl = "{$root}/pluginfile.php/{$context->id}/mod_hvp/content/{$id}";

        $settings['contents']['cid-' . $id]['contentUrl'] = $contenturl;

    }

    $PAGE->requires->data_for_js('H5PIntegration', $settings, true);

}

/**

 * Add core JS and CSS to page.

 *

 * @param moodle_page $page

 * @param moodle_url|string $liburl

 * @param array|null $settings

 * @throws \coding_exception

 */

function hvp_admin_add_generic_css_and_js($page, $liburl, $settings = null) {

    // @codingStandardsIgnoreLine

    foreach (\H5PCore::$adminScripts as $script) {

        $page->requires->js(new moodle_url($liburl . $script . hvp_get_cache_buster()), true);

    }

    if ($settings === null) {

        $settings = array();

    }

    $settings['containerSelector'] = '#h5p-admin-container';

    $settings['l10n'] = array(

        'NA' => get_string('notapplicable', 'hvp'),

        'viewLibrary' => '',

        'deleteLibrary' => '',

        'upgradeLibrary' => get_string('upgradelibrarycontent', 'hvp')

    );

    $page->requires->data_for_js('H5PAdminIntegration', $settings, true);

    $page->requires->css(new moodle_url($liburl . 'styles/h5p.css' . hvp_get_cache_buster()));

    $page->requires->css(new moodle_url($liburl . 'styles/h5p-admin.css' . hvp_get_cache_buster()));

    // Add settings.

    $page->requires->data_for_js('h5p', hvp_get_core_settings(\context_system::instance()), true);

}

/**

 * Get a query string with the plugin version number to include at the end

 * of URLs. This is used to force the browser to reload the asset when the

 * plugin is updated.

 *

 * @return string

 */

function hvp_get_cache_buster() {

    return '?ver=' . get_config('mod_hvp', 'version');

}

/**

 * Restrict access to a given content type.

 *

 * @param int $library_id

 * @param bool $restrict

 */

function hvp_restrict_library($libraryid, $restrict) {

    global $DB;

    $DB->update_record('hvp_libraries', (object) array(

        'id' => $libraryid,

        'restricted' => $restrict ? 1 : 0

    ));

}

/**

 * Handle content upgrade progress

 *

 * @method hvp_content_upgrade_progress

 * @param  int $library_id

 * @return object An object including the json content for the H5P instances

 *                (maximum 40) that should be upgraded.

 */

function hvp_content_upgrade_progress($libraryid) {

    global $DB;

    $tolibraryid = filter_input(INPUT_POST, 'libraryId');

    // Verify security token.

    if (!\H5PCore::validToken('contentupgrade', required_param('token', PARAM_RAW))) {

        print get_string('upgradeinvalidtoken', 'hvp');

        return;

    }

    // Get the library we're upgrading to.

    $tolibrary = $DB->get_record('hvp_libraries', array(

        'id' => $tolibraryid

    ));

    if (!$tolibrary) {

        print get_string('upgradelibrarymissing', 'hvp');

        return;

    }

    // Prepare response.

    $out = new stdClass();

    $out->params = array();

    $out->token = \H5PCore::createToken('contentupgrade');

    $out->metadata = array();

    // Prepare our interface.

    $interface = \mod_hvp\framework::instance('interface');

    // Get updated params.

    $params = filter_input(INPUT_POST, 'params');

    if ($params !== null) {

        // Update params.

        $params = json_decode($params);

        foreach ($params as $id => $param) {

            $upgraded = json_decode($param);

            $metadata = isset($upgraded->metadata) ? $upgraded->metadata : array();

            $fields = array_merge(\H5PMetadata::toDBArray($metadata, false, false), array(

                'id' => $id,

                'main_library_id' => $tolibrary->id,

                'json_content' => json_encode($upgraded->params),

                'filtered' => ''

            ));

            $DB->update_record('hvp', $fields);

            // Log content upgrade successful.

            new \mod_hvp\event(

                'content', 'upgrade',

                $id, $DB->get_field_sql("SELECT name FROM {hvp} WHERE id = ?", array($id)),

                $tolibrary->machine_name, $tolibrary->major_version . '.' . $tolibrary->minor_version

            );

        }

    }

    // Determine if any content has been skipped during the process.

    $skipped = filter_input(INPUT_POST, 'skipped');

    if ($skipped !== null) {

        $out->skipped = json_decode($skipped);

        // Clean up input, only numbers.

        foreach ($out->skipped as $i => $id) {

            $out->skipped[$i] = intval($id);

        }

        $skipped = implode(',', $out->skipped);

    } else {

        $out->skipped = array();

    }

    // Get number of contents for this library.

    $out->left = $interface->getNumContent($libraryid, $skipped);

    if ($out->left) {

        $skipquery = empty($skipped) ? '' : " AND id NOT IN ($skipped)";

        // Find the 40 first contents using this library version and add to params.

        $results = $DB->get_records_sql(

            "SELECT id, json_content as params, name as title, authors, source, year_from, year_to,

                    license, license_version, changes, license_extras, author_comments, default_language,

                    a11y_title

               FROM {hvp}

              WHERE main_library_id = ?

                    {$skipquery}

           ORDER BY name ASC", array($libraryid), 0 , 40

        );

        foreach ($results as $content) {

            $out->params[$content->id] = '{"params":' . $content->params .

                                         ',"metadata":' . \H5PMetadata::toJSON($content) . '}';

        }

    }

    return $out;

}

/**

 * Gets the information needed when content is upgraded

 *

 * @method hvp_get_library_upgrade_info

 * @param  string $name

 * @param  int $major

 * @param  int $minor

 * @return object Library metadata including name, version, semantics and path

 *                to upgrade script

 */

function hvp_get_library_upgrade_info($name, $major, $minor) {

    $library = (object) array(

        'name' => $name,

        'version' => (object) array(

            'major' => $major,

            'minor' => $minor

        )

    );

    $core = \mod_hvp\framework::instance();

    $library->semantics = $core->loadLibrarySemantics($library->name, $library->version->major, $library->version->minor);

    $context = \context_system::instance();

    $libraryfoldername = "{$library->name}-{$library->version->major}.{$library->version->minor}";

    if (\mod_hvp\file_storage::fileExists($context->id, 'libraries', '/' . $libraryfoldername . '/', 'upgrades.js')) {

        $basepath = \mod_hvp\view_assets::getsiteroot() . '/';

        $library->upgradesScript = "{$basepath}pluginfile.php/{$context->id}/mod_hvp/libraries/{$libraryfoldername}/upgrades.js";

    }

    return $library;

}

/**

 * Check permissions to view given user's results

 *

 * @param int $userid Id of the user the results belong to

 * @param context $context Current context, usually course context

 *

 * @return bool true if current user has permission to view given user results

 */

function hvp_has_view_results_permission($userid, $context) {

    global $USER;

    // Check if user can view all results.

    if (has_capability('mod/hvp:viewallresults', $context)) {

        return true;

    }

    // Check if viewing own results, and have permission for it.

    return $userid === (int) $USER->id ? has_capability('mod/hvp:viewresults', $context) : false;

}

/**

 * Require view results capability for this page

 *

 * @param int $userid User id who owns results

 * @param context $context Current context

 * @param int $redirectcontentid Redirect to this content id if not allowed

 *  to view own results

 */

function hvp_require_view_results_permission($userid, $context, $redirectcontentid = null) {

    global $USER;

    if (!hvp_has_view_results_permission($userid, $context)) {

        if ($userid === (int) $USER->id && isset($redirectcontentid)) {

            // Not allowed to view own results, redirect.

            redirect(new moodle_url('/mod/hvp/view.php', ['id' => $redirectcontentid]));

        } else {

            // Other user's results, require capability to view all results.

            require_capability('mod/hvp:viewallresults', $context);

        }

    }

}

/**

 * Sends notification messages to the interested parties that assign the role capability

 *

 * @param object $recipient user object of the intended recipient

 * @param $submitter

 * @param object $a associative array of replaceable fields for the templates

 *

 * @return int|false as for {@link message_send()}.

 * @throws coding_exception

 */

function hvp_send_notification($recipient, $submitter, $a) {

    // Recipient info for template.

    $a->useridnumber = $recipient->id;

    $a->username     = fullname($recipient);

    $a->userusername = $recipient->username;

    // Prepare the message.

    $message                    = new message();

    $message->component         = 'mod_hvp';

    $message->name              = 'submission';

    $message->userfrom          = $submitter;

    $message->userto            = $recipient;

    $message->subject           = get_string('emailnotifysubject', 'hvp', $a);

    $message->fullmessage       = get_string('emailnotifybody', 'hvp', $a);

    $message->fullmessageformat = FORMAT_PLAIN;

    $message->fullmessagehtml   = '';

    $message->smallmessage      = get_string('emailnotifysmall', 'hvp', $a);

    $message->courseid          = $a->courseid;

    $message->contexturl     = $a->hvpreporturl;

    $message->contexturlname = $a->hvpname;

    return message_send($message);

}

/**

 * Sends a confirmation message to the student confirming that the attempt was processed.

 *

 * @param object $a useful information that can be used in the message

 *      subject and body.

 *

 * @return int|false as for {@link message_send()}.

 * @throws coding_exception

 */

function hvp_send_confirmation($recipient, $a) {

    // Add information about the recipient to $a.

    $a->username     = fullname($recipient);

    $a->userusername = $recipient->username;

    // Prepare the message.

    $eventdata               = new \core\message\message();

    $eventdata->courseid     = $a->courseid;

    $eventdata->component    = 'mod_hvp';

    $eventdata->name         = 'confirmation';

    $eventdata->notification = 1;

    $eventdata->userfrom          = core_user::get_noreply_user();

    $eventdata->userto            = $recipient;

    $eventdata->subject           = get_string('emailconfirmsubject', 'hvp', $a);

    $eventdata->fullmessage       = get_string('emailconfirmbody', 'hvp', $a);

    $eventdata->fullmessageformat = FORMAT_PLAIN;

    $eventdata->fullmessagehtml   = '';

    $eventdata->smallmessage   = get_string('emailconfirmsmall', 'hvp', $a);

    $eventdata->contexturl     = $a->hvpurl;

    $eventdata->contexturlname = $a->hvpname;

    return message_send($eventdata);

}

/**

 * Send all the required messages when a h5p attempt is submitted.

 *

 * @param object $course the course

 * @param object $hvp the h5p

 * @param object $attempt this attempt just finished

 * @param context $context the h5p context

 * @param object $cm the coursemodule for this h5p

 *

 * @return bool true if all necessary messages were sent successfully, else false.

 * @throws coding_exception

 * @throws dml_exception

 */

function hvp_send_notification_messages($course, $hvp, $attempt, $context, $cm) {

    global $CFG, $DB;

    // Do nothing if required objects not present.

    if (empty($course) or empty($hvp) or empty($attempt) or empty($context)) {

        throw new coding_exception('$course, $hvp, $attempt, $context and $cm must all be set.');

    }

    $submitter = $DB->get_record('user', array('id' => $attempt->userid), '*', MUST_EXIST);

    // Check for confirmation required.

    $sendconfirm        = false;

    $notifyexcludeusers = '';

    if (has_capability('mod/hvp:emailconfirmsubmission', $context, $submitter, false)) {

        $notifyexcludeusers = $submitter->id;

        $sendconfirm        = true;

    }

    // Check for notifications required.

    $notifyfields = 'u.id, u.username, u.idnumber, u.email, u.emailstop, u.lang,

            u.timezone, u.mailformat, u.maildisplay, u.auth, u.suspended, u.deleted, ';

    $notifyfields .= get_all_user_name_fields(true, 'u');

    $groups       = groups_get_all_groups($course->id, $submitter->id, $cm->groupingid);

    if (is_array($groups) && count($groups) > 0) {

        $groups = array_keys($groups);

    } else if (groups_get_activity_groupmode($cm, $course) != NOGROUPS) {

        // If the user is not in a group, and the hvp is set to group mode,

        // then set $groups to a non-existant id so that only users with

        // 'moodle/site:accessallgroups' get notified.

        $groups = - 1;

    } else {

        $groups = '';

    }

    $userstonotify = get_users_by_capability($context, 'mod/hvp:emailnotifysubmission',

        $notifyfields, '', '', '', $groups, $notifyexcludeusers, false, false, true);

    if (empty($userstonotify) && !$sendconfirm) {

        return true; // Nothing to do.

    }

    $a = new stdClass();

    // Course info.

    $a->courseid        = $course->id;

    $a->coursename      = $course->fullname;

    $a->courseshortname = $course->shortname;

    // H5P info.

    $a->hvpname       = $hvp->name;

    $report           = "{$CFG->wwwroot}/mod/hvp/review.php?id={$hvp->id}&course={$course->id}&user={$submitter->id}";

    $a->hvpreporturl  = $report;

    $a->hvpreportlink = '<a href="' . $a->hvpreporturl . '">' .

                        format_string($hvp->name, true, ['context' => $context]) . ' report</a>';

    $a->hvpurl        = $CFG->wwwroot . '/mod/hvp/view.php?id=' . $cm->id;

    $a->hvplink       = '<a href="' . $a->hvpurl . '">' .

                        format_string($hvp->name, true, ['context' => $context]) . '</a>';

    $a->hvpid         = $hvp->id;

    $a->hvpcmid       = $cm->id;

    // Student who sat the hvp info.

    $a->studentidnumber = $submitter->id;

    $a->studentname     = fullname($submitter);

    $a->studentusername = $submitter->username;

    $allok = true;

    // Send notifications if required.

    if (!empty($userstonotify)) {

        foreach ($userstonotify as $recipient) {

            $allok = $allok && hvp_send_notification($recipient, $submitter, $a);

        }

    }

    // Send confirmation if required. We send the student confirmation last, so

    // that if message sending is being intermittently buggy, which means we send

    // some but not all messages, and then try again later, then teachers may get

    // duplicate messages, but the student will always get exactly one.

    if ($sendconfirm) {

        $allok = $allok && hvp_send_confirmation($submitter, $a);

    }

    return $allok;

}

/**

 * Callback for the attempt_submitted event.

 * Sends out notification messages.

 *

 * @param $event

 *

 * @throws coding_exception

 * @throws dml_exception

 */

function hvp_attempt_submitted_handler($event) {

    global $DB, $PAGE;

    $course  = $DB->get_record('course', array('id' => $event->courseid));

    $cm      = get_coursemodule_from_id('hvp', $event->get_context()->instanceid, $event->courseid);

    $hvp     = $DB->get_record('hvp', array('id' => $cm->instance));

    $attempt = (object) [

        'userid' => $event->userid

    ];

    $context = context_module::instance($cm->id);

    $PAGE->set_context($context);

    hvp_send_notification_messages($course, $hvp, $attempt, $context, $cm);

}

/**

 * Check and update content hub status for shared content.

 *

 * @param $content

 */

function hvp_update_hub_status($content) {

    $synced = intval($content['synced']);

    // Only check sync status when waiting.

    if (empty($content['contentHubId']) || $synced !== H5PContentHubSyncStatus::WAITING) {

        return false;

    }

    $core = \mod_hvp\framework::instance();

    $newstate = $core->getHubContentStatus($content['contentHubId'], $synced);

    if ($newstate !== false) {

        $core->h5pF->updateContentFields($content['id'], array('synced' => $newstate));

        return $newstate;

    }

    return false;

}

/**

 * Create URL for Content Hub to download content

 *

 * @param $content

 */

function hvp_create_hub_export_url($cmid, $content) {

    // Create URL.

    $modulecontext = \context_module::instance($cmid);

    $slug          = $content['slug'] ? $content['slug'] . '-' : '';

    $filename      = "{$slug}{$content['id']}.h5p";

    $exporturl     = \moodle_url::make_pluginfile_url($modulecontext->id, 'mod_hvp', 'exports', '', '', $filename)

        ->out(false);

    // To prevent anyone else from downloading we add an extra token.

    $time  = time();

    $data  = $time . ':' . get_config('mod_hvp', 'site_uuid');

    $hash  = hash_hmac('SHA512', $data, get_config('mod_hvp', 'hub_secret'), true);

    $token = hvp_base64_encode($time) . '.' . hvp_base64_encode($hash);

    return "$exporturl?hub=$token";

}

/**

 * URL compatible base64 encoding.

 *

 * @param  string  $string

 *

 * @return string

 */

function hvp_base64_encode($string) {

    return str_replace('=', '', strtr(base64_encode($string), '+/', '-_'));

}