[Sommaire] [Imprimer]

   1  <?php
   2  // +----------------------------------------------------------------------+
   3  // | PEAR :: Cache                                                        |
   4  // +----------------------------------------------------------------------+
   5  // | Copyright (c) 1997-2003 The PHP Group                                |
   6  // +----------------------------------------------------------------------+
   7  // | This source file is subject to version 2.0 of the PHP license,       |
   8  // | that is bundled with this package in the file LICENSE, and is        |
   9  // | available at through the world-wide-web at                           |
  10  // | http://www.php.net/license/2_02.txt.                                 |
  11  // | If you did not receive a copy of the PHP license and are unable to   |
  12  // | obtain it through the world-wide-web, please send a note to          |
  13  // | license@php.net so we can mail you a copy immediately.               |
  14  // +----------------------------------------------------------------------+
  15  // | Authors: Ulf Wendel <ulf.wendel@phpdoc.de>                           |
  16  // |          Sebastian Bergmann <sb@sebastian-bergmann.de>               |
  17  // |          Chuck Hagenbuch <chuck@horde.org>                           |
  18  // +----------------------------------------------------------------------+
  19  //
  20  // $Id: db.php,v 1.5 2003/01/04 11:54:46 mj Exp $
  21  
  22  require_once  'DB.php';
  23  require_once  'Cache/Container.php';
  24  
  25  /**
  26  * PEAR/DB Cache Container.
  27  *
  28  * WARNING: Other systems might or might not support certain datatypes of
  29  * the tables shown. As far as I know there's no large binary
  30  * type in SQL-92 or SQL-99. Postgres seems to lack any
  31  * BLOB or TEXT type, for MS-SQL you could use IMAGE, don't know
  32  * about other databases. Please add sugestions for other databases to
  33  * the inline docs.
  34  *
  35  * The field 'changed' has no meaning for the Cache itself. It's just there
  36  * because it's a good idea to have an automatically updated timestamp
  37  * field for debugging in all of your tables.
  38  *
  39  * For _MySQL_ you need this DB table:
  40  *
  41  * CREATE TABLE cache (
  42  *   id          CHAR(32) NOT NULL DEFAULT '',
  43  *   cachegroup  VARCHAR(127) NOT NULL DEFAULT '',
  44  *   cachedata   BLOB NOT NULL DEFAULT '',
  45  *   userdata    VARCHAR(255) NOT NULL DEFAUL '',
  46  *   expires     INT(9) NOT NULL DEFAULT 0,
  47  *
  48  *   changed     TIMESTAMP(14) NOT NULL,
  49  *
  50  *   INDEX (expires),
  51  *   PRIMARY KEY (id, cachegroup)
  52  * )
  53  *
  54  * @author   Sebastian Bergmann <sb@sebastian-bergmann.de>
  55  * @version  $Id: db.php,v 1.5 2003/01/04 11:54:46 mj Exp $
  56  * @package  Cache
  57  */
  58  class Cache_Container_db extends Cache_Container {
  59  
  60      /**
  61      * Name of the DB table to store caching data
  62      *
  63      * @see  Cache_Container_file::$filename_prefix
  64      */
  65      var $cache_table = '';
  66  
  67      /**
  68      * PEAR DB dsn to use.
  69      *
  70      * @var  string
  71      */
  72      var $dsn = '';
  73  
  74      /**
  75      * PEAR DB object
  76      *
  77      * @var  object PEAR_DB
  78      */
  79      var $db;
  80  
  81      function Cache_Container_db($options)
  82      {
  83          if (!is_array($options) || !isset($options['dsn'])) {
  84              return new Cache_Error('No dsn specified!', __FILE__, __LINE__);
  85          }
  86  
  87          $this->setOptions($options,  array_merge($this->allowed_options, array('dsn', 'cache_table')));
  88  
  89          if (!$this->dsn)
  90              return new Cache_Error('No dsn specified!', __FILE__, __LINE__);
  91  
  92          $this->db = DB::connect($this->dsn, true);
  93          if (DB::isError($this->db)) {
  94              return new Cache_Error('DB::connect failed: ' . DB::errorMessage($this->db), __FILE__, __LINE__);
  95          } else {
  96              $this->db->setFetchMode(DB_FETCHMODE_ASSOC);
  97          }
  98      }
  99  
 100      function fetch($id, $group)
 101      {
 102          $query = sprintf("SELECT cachedata, userdata, expires FROM %s WHERE id = '%s' AND cachegroup = '%s'",
 103                           $this->cache_table,
 104                           addslashes($id),
 105                           addslashes($group)
 106                           );
 107  
 108          $res = $this->db->query($query);
 109  
 110          if (DB::isError($res))
 111              return new Cache_Error('DB::query failed: ' . DB::errorMessage($res), __FILE__, __LINE__);
 112  
 113          $row = $res->fetchRow();
 114          if (is_array($row))
 115              $data = array($row['expires'], $this->decode($row['cachedata']), $row['userdata']);
 116          else
 117              $data = array(NULL, NULL, NULL);
 118  
 119          // last used required by the garbage collection
 120          // WARNING: might be MySQL specific
 121          $query = sprintf("UPDATE %s SET changed = (NOW() + 0) WHERE id = '%s' AND cachegroup = '%s'",
 122                              $this->cache_table,
 123                              addslashes($id),
 124                              addslashes($group)
 125                            );
 126  
 127          $res = $this->db->query($query);
 128  
 129          if (DB::isError($res))
 130              return new Cache_Error('DB::query failed: ' . DB::errorMessage($res), __FILE__, __LINE__);
 131  
 132          return $data;
 133      }
 134  
 135      /**
 136      * Stores a dataset.
 137      *
 138      * WARNING: we use the SQL command REPLACE INTO this might be
 139      * MySQL specific. As MySQL is very popular the method should
 140      * work fine for 95% of you.
 141      */
 142      function save($id, $data, $expires, $group, $userdata)
 143      {
 144          $this->flushPreload($id, $group);
 145  
 146          $query = sprintf("REPLACE INTO %s (userdata, cachedata, expires, id, cachegroup) VALUES ('%s', '%s', %d, '%s', '%s')",
 147                           $this->cache_table,
 148                           addslashes($userdata),
 149                           addslashes($this->encode($data)),
 150                            $this->getExpiresAbsolute($expires) ,
 151                           addslashes($id),
 152                           addslashes($group)
 153                          );
 154  
 155          $res = $this->db->query($query);
 156  
 157          if (DB::isError($res)) {
 158              return new Cache_Error('DB::query failed: ' . DB::errorMessage($res) , __FILE__, __LINE__);
 159          }
 160      }
 161  
 162      function remove($id, $group)
 163      {
 164          $this->flushPreload($id, $group);
 165  
 166          $query = sprintf("DELETE FROM %s WHERE id = '%s' and cachegroup = '%s'",
 167                           $this->cache_table,
 168                           addslashes($id),
 169                           addslashes($group)
 170                          );
 171  
 172          $res = $this->db->query($query);
 173  
 174          if (DB::isError($res))
 175              return new Cache_Error('DB::query failed: ' . DB::errorMessage($res), __FILE__, __LINE__);
 176      }
 177  
 178      function flush($group = '')
 179      {
 180          $this->flushPreload();
 181  
 182           if ($group) {
 183              $query = sprintf("DELETE FROM %s WHERE cachegroup = '%s'", $this->cache_table, addslashes($group));
 184          } else {
 185              $query = sprintf("DELETE FROM %s", $this->cache_table);
 186          }
 187  
 188          $res = $this->db->query($query);
 189  
 190          if (DB::isError($res))
 191              return new Cache_Error('DB::query failed: ' . DB::errorMessage($res), __FILE__, __LINE__);
 192      }
 193  
 194      function idExists($id, $group)
 195      {
 196          $query = sprintf("SELECT id FROM %s WHERE ID = '%s' AND cachegroup = '%s'",
 197                           $this->cache_table,
 198                           addslashes($id),
 199                           addslashes($group)
 200                          );
 201  
 202          $res = $this->db->query($query);
 203  
 204          if (DB::isError($res))
 205              return new Cache_Error('DB::query failed: ' . DB::errorMessage($res), __FILE__, __LINE__);
 206  
 207          $row = $res->fetchRow();
 208  
 209          if (is_array($row)) {
 210              return true;
 211          } else {
 212              return false;
 213          }
 214      }
 215  
 216      function garbageCollection($maxlifetime)
 217      {
 218          $this->flushPreload();
 219  
 220          $query = sprintf('DELETE FROM %s WHERE (expires <= %d AND expires > 0) OR changed <= %d',
 221                           $this->cache_table,
 222                           time(),
 223                           time() - $maxlifetime
 224                         );
 225  
 226          $res = $this->db->query($query);
 227  
 228          $query = sprintf('select sum(length(cachedata)) as CacheSize from %s',
 229                           $this->cache_table
 230                         );
 231          $cachesize = $this->db->GetOne($query);
 232          if (DB::isError($cachesize)) {
 233              return new Cache_Error('DB::query failed: ' . DB::errorMessage($cachesize), __FILE__, __LINE__);
 234          }
 235  
 236          //if cache is to big.
 237          if ($cachesize > $this->highwater)
 238          {
 239              //find the lowwater mark.
 240              $query = sprintf('select length(cachedata) as size, changed from %s order by changed DESC',
 241                                       $this->cache_table
 242                         );
 243              $res = $this->db->query($query);
 244              if (DB::isError($res)) {
 245                  return new Cache_Error('DB::query failed: ' . DB::errorMessage($res), __FILE__, __LINE__);
 246              }
 247  
 248              $numrows = $this->db->numRows($res);
 249              $keep_size = 0;
 250              while ($keep_size < $this->lowwater && $numrows--) {
 251                  $entry = $res->fetchRow(DB_FETCHMODE_ASSOC);
 252                  $keep_size += $entry['size'];
 253              }
 254  
 255              //delete all entries, which were changed before the "lowwwater mark"
 256              $query = sprintf('delete from %s where changed <= '.($entry['changed'] ? $entry['changed'] : 0),
 257                                       $this->cache_table
 258                                     );
 259              $res = $this->db->query($query);
 260          }
 261  
 262          if (DB::isError($res)) {
 263              return new Cache_Error('DB::query failed: ' . DB::errorMessage($res), __FILE__, __LINE__);
 264          }
 265      }
 266  
 267  }
 268  ?>