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 mod_bigbluebuttonbn;

use cache;

use cache_store;

use context_course;

use core_tag_tag;

use Exception;

use Firebase\JWT\Key;

use mod_bigbluebuttonbn\local\config;

use mod_bigbluebuttonbn\local\exceptions\bigbluebutton_exception;

use mod_bigbluebuttonbn\local\exceptions\meeting_join_exception;

use mod_bigbluebuttonbn\local\helpers\roles;

use mod_bigbluebuttonbn\local\proxy\bigbluebutton_proxy;

use stdClass;

/**

 * Class to describe a BBB Meeting.

 *

 * @package   mod_bigbluebuttonbn

 * @copyright 2021 Andrew Lyons <andrew@nicols.co.uk>

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

 */

class meeting {

    /** @var instance The bbb instance */

    protected $instance;

    /** @var stdClass Info about the meeting */

    protected $meetinginfo = null;

    /**

     * Constructor for the meeting object.

     *

     * @param instance $instance

     */

    public function __construct(instance $instance) {

        $this->instance = $instance;

    }

    /**

     * Helper to join a meeting.

     *

     *

     * It will create the meeting if not already created.

     *

     * @param instance $instance

     * @param int $origin

     * @return string

     * @throws meeting_join_exception this is sent if we cannot join (meeting full, user needs to wait...)

     */

    public static function join_meeting(instance $instance, $origin = logger::ORIGIN_BASE): string {

        // See if the session is in progress.

        $meeting = new meeting($instance);

        // As the meeting doesn't exist, try to create it.

        if (empty($meeting->get_meeting_info(true)->createtime)) {

            $meeting->create_meeting();

        }

        return $meeting->join($origin);

    }

    /**

     * Get currently stored meeting info

     *

     * @return stdClass

     */

    public function get_meeting_info() {

        if (!$this->meetinginfo) {

            $this->meetinginfo = $this->do_get_meeting_info();

        }

        return $this->meetinginfo;

    }

    /**

     * Return meeting information for the specified instance.

     *

     * @param instance $instance

     * @param bool $updatecache Whether to update the cache when fetching the information

     * @return stdClass

     */

    public static function get_meeting_info_for_instance(instance $instance, bool $updatecache = false): stdClass {

        $meeting = new self($instance);

        return $meeting->do_get_meeting_info($updatecache);

    }

    /**

     * Helper function returns a sha1 encoded string that is unique and will be used as a seed for meetingid.

     *

     * @return string

     */

    public static function get_unique_meetingid_seed() {

        global $DB;

        do {

            $encodedseed = sha1(plugin::random_password(12));

            $meetingid = (string) $DB->get_field('bigbluebuttonbn', 'meetingid', ['meetingid' => $encodedseed]);

        } while ($meetingid == $encodedseed);

        return $encodedseed;

    }

    /**

     * Is meeting running ?

     *

     * @return bool

     */

    public function is_running() {

        return $this->get_meeting_info()->statusrunning ?? false;

    }

    /**

     * Force update the meeting in cache.

     */

    public function update_cache() {

        $this->meetinginfo = $this->do_get_meeting_info(true);

    }

    /**

     * Get meeting attendees

     *

     * @return array[]

     */

    public function get_attendees(): array {

        return $this->get_meeting_info()->attendees ?? [];

    }

    /**

     * Can the meeting be joined ?

     *

     * @return bool

     */

    public function can_join() {

        return $this->get_meeting_info()->canjoin;

    }

    /**

     * Total number of moderators and viewers.

     *

     * @return int

     */

    public function get_participant_count() {

        return $this->get_meeting_info()->totalusercount;

    }

    /**

     * Creates a bigbluebutton meeting, send the message to BBB and returns the response in an array.

     *

     * @return array

     */

    public function create_meeting() {

        $data = $this->create_meeting_data();

        $metadata = $this->create_meeting_metadata();

        $presentation = $this->instance->get_presentation_for_bigbluebutton_upload(); // The URL must contain nonce.

        $presentationname = $presentation['name'] ?? null;

        $presentationurl = $presentation['url'] ?? null;

        $response = bigbluebutton_proxy::create_meeting(

            $data,

            $metadata,

            $presentationname,

            $presentationurl,

            $this->instance->get_instance_id()

        );

        // New recording management: Insert a recordingID that corresponds to the meeting created.

        if ($this->instance->is_recorded()) {

            $recording = new recording(0, (object) [

                'courseid' => $this->instance->get_course_id(),

                'bigbluebuttonbnid' => $this->instance->get_instance_id(),

                'recordingid' => $response['internalMeetingID'],

                'groupid' => $this->instance->get_group_id()]

            );

            $recording->create();

        }

        return $response;

    }

    /**

     * Send an end meeting message to BBB server

     */

    public function end_meeting() {

        bigbluebutton_proxy::end_meeting(

            $this->instance->get_meeting_id(),

            $this->instance->get_moderator_password(),

            $this->instance->get_instance_id()

        );

    }

    /**

     * Get meeting join URL

     *

     * @return string

     */

    public function get_join_url(): string {

        return bigbluebutton_proxy::get_join_url($this->instance, $this->get_meeting_info()->createtime);

    }

    /**

     * Get meeting join URL for guest

     *

     * @param string $userfullname

     * @return string

     */

    public function get_guest_join_url(string $userfullname): string {

        return bigbluebutton_proxy::get_guest_join_url($this->instance, $this->get_meeting_info()->createtime, $userfullname);

    }

    /**

     * Return meeting information for this meeting.

     *

     * @param bool $updatecache Whether to update the cache when fetching the information

     * @return stdClass

     */

    protected function do_get_meeting_info(bool $updatecache = false): stdClass {

        $instance = $this->instance;

        $meetinginfo = (object) [

            'instanceid' => $instance->get_instance_id(),

            'bigbluebuttonbnid' => $instance->get_instance_id(),

            'groupid' => $instance->get_group_id(),

            'meetingid' => $instance->get_meeting_id(),

            'cmid' => $instance->get_cm_id(),

            'ismoderator' => $instance->is_moderator(),

            'joinurl' => $instance->get_join_url()->out(),

            'userlimit' => $instance->get_user_limit(),

            'presentations' => [],

        ];

        if ($instance->get_instance_var('openingtime')) {

            $meetinginfo->openingtime = intval($instance->get_instance_var('openingtime'));

        }

        if ($instance->get_instance_var('closingtime')) {

            $meetinginfo->closingtime = intval($instance->get_instance_var('closingtime'));

        }

        $activitystatus = bigbluebutton_proxy::view_get_activity_status($instance);

        // This might raise an exception if info cannot be retrieved.

        // But this might be totally fine as the meeting is maybe not yet created on BBB side.

        $totalusercount = 0;

        // This is the default value for any meeting that has not been created.

        $meetinginfo->statusrunning = false;

        $meetinginfo->createtime = null;

        $info = self::retrieve_cached_meeting_info($this->instance, $updatecache);

        if (!empty($info)) {

            $meetinginfo->statusrunning = $info['running'] === 'true';

            $meetinginfo->createtime = $info['createTime'] ?? null;

            $totalusercount = isset($info['participantCount']) ? $info['participantCount'] : 0;

        }

        $meetinginfo->statusclosed = $activitystatus === 'ended';

        $meetinginfo->statusopen = !$meetinginfo->statusrunning && $activitystatus === 'open';

        $meetinginfo->totalusercount = $totalusercount;

        $canjoin = !$instance->user_must_wait_to_join() || $meetinginfo->statusrunning;

        // Limit has not been reached.

        $canjoin = $canjoin && (!$instance->has_user_limit_been_reached($totalusercount));

        // User should only join during scheduled session start and end time, if defined.

        $canjoin = $canjoin && ($instance->is_currently_open());

        // Double check that the user has the capabilities to join.

        $canjoin = $canjoin && $instance->can_join();

        $meetinginfo->canjoin = $canjoin;

        // If user is administrator, moderator or if is viewer and no waiting is required, join allowed.

        if ($meetinginfo->statusrunning) {

            $meetinginfo->startedat = floor(intval($info['startTime']) / 1000); // Milliseconds.

            $meetinginfo->moderatorcount = $info['moderatorCount'];

            $meetinginfo->moderatorplural = $info['moderatorCount'] > 1;

            $meetinginfo->participantcount = $totalusercount - $meetinginfo->moderatorcount;

            $meetinginfo->participantplural = $meetinginfo->participantcount > 1;

        }

        $meetinginfo->statusmessage = $this->get_status_message($meetinginfo, $instance);

        $presentation = $instance->get_presentation(); // This is for internal use.

        if (!empty($presentation)) {

            $meetinginfo->presentations[] = $presentation;

        }

        $meetinginfo->attendees = [];

        if (!empty($info['attendees'])) {

            // Ensure each returned attendee is cast to an array, rather than a simpleXML object.

            foreach ($info['attendees'] as $attendee) {

                $meetinginfo->attendees[] = (array) $attendee;

            }

        }

        $meetinginfo->guestaccessenabled = $instance->is_guest_allowed();

        if ($meetinginfo->guestaccessenabled && $instance->is_moderator()) {

            $meetinginfo->guestjoinurl = $instance->get_guest_access_url()->out();

            $meetinginfo->guestpassword = $instance->get_guest_access_password();

        }

        $meetinginfo->features = $instance->get_enabled_features();

        return $meetinginfo;

    }

    /**

     * Deduce status message from the current meeting info and the instance

     *

     * Returns the human-readable message depending on if the user must wait to join, the meeting has not

     * yet started ...

     * @param object $meetinginfo

     * @param instance $instance

     * @return string

     */

    protected function get_status_message(object $meetinginfo, instance $instance): string {

        if ($instance->has_user_limit_been_reached($meetinginfo->totalusercount)) {

            return get_string('view_message_conference_user_limit_reached', 'bigbluebuttonbn');

        }

        if ($meetinginfo->statusrunning) {

            return get_string('view_message_conference_in_progress', 'bigbluebuttonbn');

        }

        if ($instance->user_must_wait_to_join() && !$instance->user_can_force_join()) {

            return get_string('view_message_conference_wait_for_moderator', 'bigbluebuttonbn');

        }

        if ($instance->before_start_time()) {

            return get_string('view_message_conference_not_started', 'bigbluebuttonbn');

        }

        if ($instance->has_ended()) {

            return get_string('view_message_conference_has_ended', 'bigbluebuttonbn');

        }

        return get_string('view_message_conference_room_ready', 'bigbluebuttonbn');

    }

    /**

     * Gets a meeting info object cached or fetched from the live session.

     *

     * @param instance $instance

     * @param bool $updatecache

     *

     * @return array

     */

    protected static function retrieve_cached_meeting_info(instance $instance, $updatecache = false) {

        $meetingid = $instance->get_meeting_id();

        $cachettl = (int) config::get('waitformoderator_cache_ttl');

        $cache = cache::make_from_params(cache_store::MODE_APPLICATION, 'mod_bigbluebuttonbn', 'meetings_cache');

        $result = $cache->get($meetingid);

        $now = time();

        if (!$updatecache && !empty($result) && $now < ($result['creation_time'] + $cachettl)) {

            // Use the value in the cache.

            return (array) json_decode($result['meeting_info']);

        }

        // We set the cache to an empty value so then if get_meeting_info raises an exception we still have the

        // info about the last creation_time, so we don't ask the server again for a bit.

        $defaultcacheinfo = ['creation_time' => time(), 'meeting_info' => '[]'];

        // Pings again and refreshes the cache.

        try {

            $meetinginfo = bigbluebutton_proxy::get_meeting_info($meetingid);

            $cache->set($meetingid, ['creation_time' => time(), 'meeting_info' => json_encode($meetinginfo)]);

        } catch (bigbluebutton_exception $e) {

            // The meeting is not created on BBB side, so we set the value in the cache so we don't poll again

            // and return an empty array.

            $cache->set($meetingid, $defaultcacheinfo);

            return [];

        }

        return $meetinginfo;

    }

    /**

     * Conversion between form settings and lockSettings as set in BBB API.

     */

    const LOCK_SETTINGS_MEETING_DATA = [

        'disablecam' => 'lockSettingsDisableCam',

        'disablemic' => 'lockSettingsDisableMic',

        'disableprivatechat' => 'lockSettingsDisablePrivateChat',

        'disablepublicchat' => 'lockSettingsDisablePublicChat',

        'disablenote' => 'lockSettingsDisableNote',

        'hideuserlist' => 'lockSettingsHideUserList'

    ];

    /**

     * Helper to prepare data used for create meeting.

     * @todo moderatorPW and attendeePW will be removed from create after release of BBB v2.6.

     *

     * @return array

     */

    protected function create_meeting_data() {

        $data = ['meetingID' => $this->instance->get_meeting_id(),

            'name' => \mod_bigbluebuttonbn\plugin::html2text($this->instance->get_meeting_name(), 64),

            'attendeePW' => $this->instance->get_viewer_password(),

            'moderatorPW' => $this->instance->get_moderator_password(),

            'logoutURL' => $this->instance->get_logout_url()->out(false),

        ];

        $data['record'] = $this->instance->should_record() ? 'true' : 'false';

        // Check if auto_start_record is enable.

        if ($data['record'] == 'true' && $this->instance->should_record_from_start()) {

            $data['autoStartRecording'] = 'true';

        }

        // Check if hide_record_button is enable.

        if (!$this->instance->should_show_recording_button()) {

            $data['allowStartStopRecording'] = 'false';

        }

        $data['welcome'] = trim($this->instance->get_welcome_message());

        $voicebridge = intval($this->instance->get_voice_bridge());

        if ($voicebridge > 0 && $voicebridge < 79999) {

            $data['voiceBridge'] = $voicebridge;

        }

        $maxparticipants = intval($this->instance->get_user_limit());

        if ($maxparticipants > 0) {

            $data['maxParticipants'] = $maxparticipants;

        }

        if ($this->instance->get_mute_on_start()) {

            $data['muteOnStart'] = 'true';

        }

        // Here a bit of a change compared to the API default behaviour: we should not allow guest to join

        // a meeting managed by Moodle by default.

        if ($this->instance->is_guest_allowed()) {

            $data['guestPolicy'] = $this->instance->is_moderator_approval_required() ? 'ASK_MODERATOR' : 'ALWAYS_ACCEPT';

        }

        // Locks settings.

        foreach (self::LOCK_SETTINGS_MEETING_DATA as $instancevarname => $lockname) {

            $instancevar = $this->instance->get_instance_var($instancevarname);

            if (!is_null($instancevar)) {

                $data[$lockname] = $instancevar ? 'true' : 'false';

                if ($instancevar) {

                    $data['lockSettingsLockOnJoin'] = 'true'; // This will be locked whenever one settings is locked.

                }

            }

        }

        return $data;

    }

    /**

     * Helper for preparing metadata used while creating the meeting.

     *

     * @return array

     */

    protected function create_meeting_metadata() {

        global $USER;

        // Create standard metadata.

        $origindata = $this->instance->get_origin_data();

        $metadata = [

            'bbb-origin' => $origindata->origin,

            'bbb-origin-version' => $origindata->originVersion,

            'bbb-origin-server-name' => $origindata->originServerName,

            'bbb-origin-server-common-name' => $origindata->originServerCommonName,

            'bbb-origin-tag' => $origindata->originTag,

            'bbb-context' => $this->instance->get_course()->fullname,

            'bbb-context-id' => $this->instance->get_course_id(),

            'bbb-context-name' => trim(html_to_text($this->instance->get_course()->fullname, 0)),

            'bbb-context-label' => trim(html_to_text($this->instance->get_course()->shortname, 0)),

            'bbb-recording-name' => plugin::html2text($this->instance->get_meeting_name(), 64),

            'bbb-recording-description' => plugin::html2text($this->instance->get_meeting_description(),

                64),

            'bbb-recording-tags' =>

                implode(',', core_tag_tag::get_item_tags_array('core',

                    'course_modules', $this->instance->get_cm_id())), // Same as $id.

        ];

        // Special metadata for recording processing.

        if ((boolean) config::get('recordingstatus_enabled')) {

            $metadata["bn-recording-status"] = json_encode(

                [

                    'email' => ['"' . fullname($USER) . '" <' . $USER->email . '>'],

                    'context' => $this->instance->get_view_url(),

                ]

            );

        }

        if ((boolean) config::get('recordingready_enabled')) {

            $metadata['bbb-recording-ready-url'] = $this->instance->get_record_ready_url()->out(false);

        }

        if ((boolean) config::get('meetingevents_enabled')) {

            $metadata['analytics-callback-url'] = $this->instance->get_meeting_event_notification_url()->out(false);

        }

        return $metadata;

    }

    /**

     * Helper for responding when storing live meeting events is requested.

     *

     * The callback with a POST request includes:

     *  - Authentication: Bearer <A JWT token containing {"exp":<TIMESTAMP>} encoded with HS512>

     *  - Content Type: application/json

     *  - Body: <A JSON Object>

     *

     * @param instance $instance

     * @param object $data

     * @return string

     */

    public static function meeting_events(instance $instance, object $data): string {

        $bigbluebuttonbn = $instance->get_instance_data();

        // Validate that the bigbluebuttonbn activity corresponds to the meeting_id received.

        $meetingidelements = explode('[', $data->{'meeting_id'});

        $meetingidelements = explode('-', $meetingidelements[0]);

        if (!isset($bigbluebuttonbn) || $bigbluebuttonbn->meetingid != $meetingidelements[0]) {

            return 'HTTP/1.0 410 Gone. The activity may have been deleted';

        }

        // We make sure events are processed only once.

        $overrides = ['meetingid' => $data->{'meeting_id'}];

        $meta['internalmeetingid'] = $data->{'internal_meeting_id'};

        $meta['callback'] = 'meeting_events';

        $meta['meetingid'] = $data->{'meeting_id'};

        $eventcount = logger::log_event_callback($instance, $overrides, $meta);

        if ($eventcount === 1) {

            // Process the events.

            self::process_meeting_events($instance, $data);

            return 'HTTP/1.0 200 Accepted. Enqueued.';

        } else {

            return 'HTTP/1.0 202 Accepted. Already processed.';

        }

    }

    /**

     * Helper function enqueues list of meeting events to be stored and processed as for completion.

     *

     * @param instance $instance

     * @param stdClass $jsonobj

     */

    protected static function process_meeting_events(instance $instance, stdClass $jsonobj) {

        $meetingid = $jsonobj->{'meeting_id'};

        $recordid = $jsonobj->{'internal_meeting_id'};

        $attendees = $jsonobj->{'data'}->{'attendees'};

        foreach ($attendees as $attendee) {

            $userid = $attendee->{'ext_user_id'};

            $overrides['meetingid'] = $meetingid;

            $overrides['userid'] = $userid;

            $meta['recordid'] = $recordid;

            $meta['data'] = $attendee;

            // Stores the log.

            logger::log_event_summary($instance, $overrides, $meta);

            // Enqueue a task for processing the completion.

            bigbluebutton_proxy::enqueue_completion_event($instance->get_instance_data(), $userid);

        }

    }

    /**

     * Prepare join meeting action

     *

     * @param int $origin

     * @return void

     */

    protected function prepare_meeting_join_action(int $origin) {

        $this->do_get_meeting_info(true);

        if ($this->is_running()) {

            if ($this->instance->has_user_limit_been_reached($this->get_participant_count())) {

                throw new meeting_join_exception('userlimitreached');

            }

        } else if ($this->instance->user_must_wait_to_join()) {

            // If user is not administrator nor moderator (user is student) and waiting is required.

            throw new meeting_join_exception('waitformoderator');

        }

        // Moodle event logger: Create an event for meeting joined.

        logger::log_meeting_joined_event($this->instance, $origin);

        // Before executing the redirect, increment the number of participants.

        roles::participant_joined($this->instance->get_meeting_id(), $this->instance->is_moderator());

    }

    /**

     * Join a meeting.

     *

     * @param int $origin The spec

     * @return string The URL to redirect to

     * @throws meeting_join_exception

     */

    public function join(int $origin): string {

        $this->prepare_meeting_join_action($origin);

        return $this->get_join_url();

    }

    /**

     * Join a meeting as a guest.

     *

     * @param int $origin The spec

     * @param string $userfullname Fullname for the guest user

     * @return string The URL to redirect to

     * @throws meeting_join_exception

     */

    public function guest_join(int $origin, string $userfullname): string {

        $this->prepare_meeting_join_action($origin);

        return $this->get_join_url();

    }

}