plugins/Realtime/Realtime_channel.php

   1 <?php
   2 /**
   3  * StatusNet - the distributed open-source microblogging tool
   4  * Copyright (C) 2011, StatusNet, Inc.
   5  *
   6  * A channel for real-time browser data
   7  *
   8  * PHP version 5
   9  *
  10  * This program is free software: you can redistribute it and/or modify
  11  * it under the terms of the GNU Affero General Public License as published by
  12  * the Free Software Foundation, either version 3 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU Affero General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU Affero General Public License
  21  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  22  *
  23  * @category  Realtime
  24  * @package   StatusNet
  25  * @author    Evan Prodromou <evan@status.net>
  26  * @copyright 2011 StatusNet, Inc.
  27  * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPL 3.0
  28  * @link      http://status.net/
  29  */
  30
  31 if (!defined('STATUSNET')) {
  32     exit(1);
  33 }
  34
  35 /**
  36  * A channel for real-time browser data
  37  *
  38  * For each user currently browsing the site, we want to know which page they're on
  39  * so we can send real-time updates to their browser.
  40  *
  41  * @category Realtime
  42  * @package  StatusNet
  43  * @author   Evan Prodromou <evan@status.net>
  44  * @license  http://www.fsf.org/licensing/licenses/agpl.html AGPLv3
  45  * @link     http://status.net/
  46  *
  47  * @see      DB_DataObject
  48  */
  49
  50 class Realtime_channel extends Managed_DataObject
  51 {
  52         const TIMEOUT = 1800; // 30 minutes
  53
  54     public $__table = 'realtime_channel'; // table name
  55
  56     public $user_id;       // int -> user.id, can be null
  57     public $action;        // string
  58     public $arg1;          // argument
  59     public $arg2;          // argument, usually null
  60     public $channel_key;   // 128-bit shared secret key
  61     public $audience;      // listener count
  62     public $created;       // created date
  63     public $modified;      // modified date
  64
  65     /**
  66      * Get an instance by key
  67      *
  68      * This is a utility method to get a single instance with a given key value.
  69      *
  70      * @param string $k Key to use to lookup (usually 'user_id' for this class)
  71      * @param mixed  $v Value to lookup
  72      *
  73      * @return Realtime_channel object found, or null for no hits
  74      *
  75      */
  76     function staticGet($k, $v=null)
  77     {
  78         return Managed_DataObject::staticGet('Realtime_channel', $k, $v);
  79     }
  80
  81     /**
  82      * Get an instance by compound key
  83      *
  84      * @param array $kv array of key-value mappings
  85      *
  86      * @return Realtime_channel object found, or null for no hits
  87      *
  88      */
  89     function pkeyGet($kv)
  90     {
  91         return Managed_DataObject::pkeyGet('Realtime_channel', $kv);
  92     }
  93
  94     /**
  95      * The One True Thingy that must be defined and declared.
  96      */
  97     public static function schemaDef()
  98     {
  99         return array(
 100             'description' => 'A channel of realtime notice data',
 101             'fields' => array(
 102                 'user_id' => array('type' => 'int',
 103                                                                    'not null' => false,
 104                                                                    'description' => 'user viewing page; can be null'),
 105                 'action' => array('type' => 'varchar',
 106                                                   'length' => 255,
 107                                                                   'not null' => true,
 108                                                                   'description' => 'page being viewed'),
 109                                 'arg1' => array('type' => 'varchar',
 110                                                             'length' => 255,
 111                                                             'not null' => false,
 112                                                             'description' => 'page argument, like username or tag'),
 113                             'arg2' => array('type' => 'varchar',
 114                                                         'length' => 255,
 115                                                         'not null' => false,
 116                                                         'description' => 'second page argument, like tag for showstream'),
 117                             'channel_key' => array('type' => 'varchar',
 118                                                    'length' => 32,
 119                                                    'not null' => true,
 120                                                    'description' => 'shared secret key for this channel'),
 121                             'audience' => array('type' => 'integer',
 122                                     'not null' => true,
 123                                     'default' => 0,
 124                                     'description' => 'reference count'),
 125                 'created' => array('type' => 'datetime',
 126                                                                    'not null' => true,
 127                                                                    'description' => 'date this record was created'),
 128                 'modified' => array('type' => 'datetime',
 129                                                                 'not null' => true,
 130                                                             'description' => 'date this record was modified'),
 131             ),
 132             'primary key' => array('channel_key'),
 133             'unique keys' => array('realtime_channel_user_page_idx' => array('user_id', 'action', 'arg1', 'arg2')),
 134             'foreign keys' => array(
 135                 'realtime_channel_user_id_fkey' => array('user', array('user_id' => 'id')),
 136             ),
 137             'indexes' => array(
 138                 'realtime_channel_modified_idx' => array('modified'),
 139                 'realtime_channel_page_idx' => array('action', 'arg1', 'arg2')
 140             ),
 141         );
 142     }
 143
 144     static function saveNew($user_id, $action, $arg1, $arg2)
 145     {
 146         $channel = new Realtime_channel();
 147
 148         $channel->user_id = $user_id;
 149         $channel->action  = $action;
 150         $channel->arg1    = $arg1;
 151         $channel->arg2    = $arg2;
 152         $channel->audience  = 1;
 153
 154         $channel->channel_key = common_good_rand(16); // 128-bit key, 32 hex chars
 155
 156         $channel->created  = common_sql_now();
 157         $channel->modified = $channel->created;
 158
 159                 $channel->insert();
 160
 161                 return $channel;
 162     }
 163
 164     static function getChannel($user_id, $action, $arg1, $arg2)
 165     {
 166         $channel = self::fetchChannel($user_id, $action, $arg1, $arg2);
 167
 168         // Ignore (and delete!) old channels
 169
 170         if (!empty($channel)) {
 171                         $modTime = strtotime($channel->modified);
 172                         if ((time() - $modTime) > self::TIMEOUT) {
 173                                 $channel->delete();
 174                                 $channel = null;
 175                         }
 176         }
 177
 178         if (empty($channel)) {
 179                 $channel = self::saveNew($user_id, $action, $arg1, $arg2);
 180         }
 181
 182         return $channel;
 183     }
 184
 185     static function getAllChannels($action, $arg1, $arg2)
 186     {
 187         $channel = new Realtime_channel();
 188
 189         $channel->action = $action;
 190
 191         if (is_null($arg1)) {
 192                 $channel->whereAdd('arg1 is null');
 193         } else {
 194                 $channel->arg1 = $arg1;
 195         }
 196
 197         if (is_null($arg2)) {
 198                 $channel->whereAdd('arg2 is null');
 199         } else {
 200                 $channel->arg2 = $arg2;
 201         }
 202
 203         $channel->whereAdd('modified > "' . common_sql_date(time() - self::TIMEOUT) . '"');
 204
 205         $channels = array();
 206
 207         if ($channel->find()) {
 208                 $channels = $channel->fetchAll();
 209         }
 210
 211         return $channels;
 212     }
 213
 214     static function fetchChannel($user_id, $action, $arg1, $arg2)
 215     {
 216         $channel = new Realtime_channel();
 217
 218         if (is_null($user_id)) {
 219                 $channel->whereAdd('user_id is null');
 220         } else {
 221                 $channel->user_id = $user_id;
 222         }
 223
 224         $channel->action = $action;
 225
 226         if (is_null($arg1)) {
 227                 $channel->whereAdd('arg1 is null');
 228         } else {
 229                 $channel->arg1 = $arg1;
 230         }
 231
 232         if (is_null($arg2)) {
 233                 $channel->whereAdd('arg2 is null');
 234         } else {
 235                 $channel->arg2 = $arg2;
 236         }
 237
 238         if ($channel->find(true)) {
 239             $channel->increment();
 240                 return $channel;
 241         } else {
 242                 return null;
 243         }
 244     }
 245
 246     function increment()
 247     {
 248         // XXX: race
 249         $orig = clone($this);
 250         $this->audience++;
 251         $this->modified = common_sql_now();
 252         $this->update($orig);
 253     }
 254
 255     function touch()
 256     {
 257         // XXX: race
 258         $orig = clone($this);
 259         $this->modified = common_sql_now();
 260         $this->update($orig);
 261     }
 262
 263     function decrement()
 264     {
 265         // XXX: race
 266         if ($this->audience == 1) {
 267             $this->delete();
 268         } else {
 269             $orig = clone($this);
 270             $this->audience--;
 271             $this->modified = common_sql_now();
 272             $this->update($orig);
 273         }
 274     }
 275 }