gnu-social/lib/modules/Realtime/actions/keepalivechannel.php

<?php
/**
 * StatusNet - the distributed open-source microblogging tool
 * Copyright (C) 2011, StatusNet, Inc.
 *
 * action periodically pinged by a page to keep a channel alive
 *
 * PHP version 5
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * @category  Realtime
 * @package   StatusNet
 * @author    Evan Prodromou <evan@status.net>
 * @copyright 2011 StatusNet, Inc.
 * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPL 3.0
 * @link      http://status.net/
 */

if (!defined('STATUSNET')) {
    // This check helps protect against security problems;
    // your code file can't be executed directly from the web.
    exit(1);
}

/**
 * Action periodically pinged by a page to keep a channel alive
 *
 * @category  Realtime
 * @package   StatusNet
 * @author    Evan Prodromou <evan@status.net>
 * @copyright 2011 StatusNet, Inc.
 * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPL 3.0
 * @link      http://status.net/
 */
class KeepalivechannelAction extends Action
{
    protected $channelKey = null;
    protected $channel = null;

    /**
     * For initializing members of the class.
     *
     * @param array $args misc. arguments
     *
     * @return bool true
     * @throws ClientException
     */
    public function prepare(array $args = []): bool
    {
        parent::prepare($args);

        if (!$this->isPost()) {
            // TRANS: Client exception. Do not translate POST.
            throw new ClientException(_m('You have to POST it.'));
        }

        $this->channelKey = $this->trimmed('channelkey');

        if (empty($this->channelKey)) {
            // TRANS: Client exception thrown when the channel key argument is missing.
            throw new ClientException(_m('No channel key argument.'));
        }

        $this->channel = Realtime_channel::getKV('channel_key', $this->channelKey);

        if (empty($this->channel)) {
            // TRANS: Client exception thrown when referring to a non-existing channel.
            throw new ClientException(_m('No such channel.'));
        }

        return true;
    }

    /**
     * Handler method
     *
     * @return void
     */
    public function handle(): void
    {
        $this->channel->touch();

        header('HTTP/1.1 204 No Content');

        return;
    }

    /**
     * Return true if read only.
     *
     * MAY override
     *
     * @param array $args other arguments
     *
     * @return bool is read only action?
     */
    public function isReadOnly($args): bool
    {
        return false;
    }
}