<?php
/**
* StatusNet - the distributed open-source microblogging tool
* Copyright (C) 2011, StatusNet, Inc.
*
* A channel for real-time browser data
*
* 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')) {
exit(1);
}
/**
* A channel for real-time browser data
*
* For each user currently browsing the site, we want to know which page they're on
* so we can send real-time updates to their browser.
*
* @category Realtime
* @package StatusNet
* @author Evan Prodromou <evan@status.net>
* @license http://www.fsf.org/licensing/licenses/agpl.html AGPLv3
* @link http://status.net/
*
* @see DB_DataObject
*/
class Realtime_channel extends Managed_DataObject
{
const TIMEOUT = 1800; // 30 minutes
public $__table = 'realtime_channel'; // table name
public $user_id; // int -> user.id, can be null
public $action; // varchar(191) not 255 because utf8mb4 takes more space
public $arg1; // varchar(191) argument not 255 because utf8mb4 takes more space
public $arg2; // varchar(191) usually null not 255 because utf8mb4 takes more space
public $channel_key; // 128-bit shared secret key
public $audience; // listener count
public $created; // created date
public $modified; // modified date
/**
* The One True Thingy that must be defined and declared.
*/
public static function schemaDef()
{
return array(
'description' => 'A channel of realtime notice data',
'fields' => array(
'user_id' => array('type' => 'int',
'not null' => false,
'description' => 'user viewing page; can be null'),
'action' => array('type' => 'varchar',
'length' => 191,
'not null' => true,
'description' => 'page being viewed'),
'arg1' => array('type' => 'varchar',
'length' => 191,
'not null' => false,
'description' => 'page argument, like username or tag'),
'arg2' => array('type' => 'varchar',
'length' => 191,
'not null' => false,
'description' => 'second page argument, like tag for showstream'),
'channel_key' => array('type' => 'varchar',
'length' => 32,
'not null' => true,
'description' => 'shared secret key for this channel'),
'audience' => array('type' => 'integer',
'not null' => true,
'default' => 0,
'description' => 'reference count'),
'created' => array('type' => 'datetime',
'not null' => true,
'description' => 'date this record was created'),
'modified' => array('type' => 'datetime',
'not null' => true,
'description' => 'date this record was modified'),
),
'primary key' => array('channel_key'),
'unique keys' => array('realtime_channel_user_page_idx' => array('user_id', 'action', 'arg1', 'arg2')),
'foreign keys' => array(
'realtime_channel_user_id_fkey' => array('user', array('user_id' => 'id')),
),
'indexes' => array(
'realtime_channel_modified_idx' => array('modified'),
'realtime_channel_page_idx' => array('action', 'arg1', 'arg2')
),
);
}
static function saveNew($user_id, $action, $arg1, $arg2)
{
$channel = new Realtime_channel();
$channel->user_id = $user_id;
$channel->action = $action;
$channel->arg1 = $arg1;
$channel->arg2 = $arg2;
$channel->audience = 1;
$channel->channel_key = common_random_hexstr(16); // 128-bit key, 32 hex chars
$channel->created = common_sql_now();
$channel->modified = $channel->created;
$channel->insert();
return $channel;
}
static function getChannel($user_id, $action, $arg1, $arg2)
{
$channel = self::fetchChannel($user_id, $action, $arg1, $arg2);
// Ignore (and delete!) old channels
if (!empty($channel)) {
$modTime = strtotime($channel->modified);
if ((time() - $modTime) > self::TIMEOUT) {
$channel->delete();
$channel = null;
}
}
if (empty($channel)) {
$channel = self::saveNew($user_id, $action, $arg1, $arg2);
}
return $channel;
}
static function getAllChannels($action, $arg1, $arg2)
{
$channel = new Realtime_channel();
$channel->action = $action;
if (is_null($arg1)) {
$channel->whereAdd('arg1 is null');
} else {
$channel->arg1 = $arg1;
}
if (is_null($arg2)) {
$channel->whereAdd('arg2 is null');
} else {
$channel->arg2 = $arg2;
}
$channel->whereAdd('modified > "' . common_sql_date(time() - self::TIMEOUT) . '"');
$channels = array();
if ($channel->find()) {
$channels = $channel->fetchAll();
}
return $channels;
}
static function fetchChannel($user_id, $action, $arg1, $arg2)
{
$channel = new Realtime_channel();
if (is_null($user_id)) {
$channel->whereAdd('user_id is null');
} else {
$channel->user_id = $user_id;
}
$channel->action = $action;
if (is_null($arg1)) {
$channel->whereAdd('arg1 is null');
} else {
$channel->arg1 = $arg1;
}
if (is_null($arg2)) {
$channel->whereAdd('arg2 is null');
} else {
$channel->arg2 = $arg2;
}
if ($channel->find(true)) {
$channel->increment();
return $channel;
} else {
return null;
}
}
function increment()
{
// XXX: race
$orig = clone($this);
$this->audience++;
$this->modified = common_sql_now();
$this->update($orig);
}
function touch()
{
// XXX: race
$orig = clone($this);
$this->modified = common_sql_now();
$this->update($orig);
}
function decrement()
{
// XXX: race
if ($this->audience == 1) {
$this->delete();
} else {
$orig = clone($this);
$this->audience--;
$this->modified = common_sql_now();
$this->update($orig);
}
}
}