[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  // +----------------------------------------------------------------------+
  18  //
  19  // $Id: phplib.php,v 1.3 2003/01/04 11:54:46 mj Exp $
  20  
  21  require_once  'Cache/Container.php';
  22  
  23  /**
  24  * Stores cache data into a database table using PHPLibs DB abstraction.
  25  *
  26  * WARNING: Other systems might or might not support certain datatypes of 
  27  * the tables shown. As far as I know there's no large binary 
  28  * type in SQL-92 or SQL-99. Postgres seems to lack any 
  29  * BLOB or TEXT type, for MS-SQL you could use IMAGE, don't know 
  30  * about other databases. Please add sugestions for other databases to 
  31  * the inline docs.
  32  *
  33  * The field 'changed' is used by the garbage collection. Depending on 
  34  * your databasesystem you might have to subclass fetch() and garbageCollection().
  35  *
  36  * For _MySQL_ you need this DB table:
  37  *
  38  * CREATE TABLE cache (
  39  *   id          CHAR(32) NOT NULL DEFAULT '',
  40  *   cachegroup  VARCHAR(127) NOT NULL DEFAULT '',
  41  *   cachedata   BLOB NOT NULL DEFAULT '',
  42  *   userdata    VARCHAR(255) NOT NULL DEFAUL '',
  43  *   expires     INT(9) NOT NULL DEFAULT 0,
  44  *  
  45  *   changed     TIMESTAMP(14) NOT NULL,
  46  *  
  47  *   INDEX (expires),
  48  *   PRIMARY KEY (id, cachegroup)
  49  * )
  50  *
  51  * 
  52  * @author   Ulf Wendel  <ulf.wendel@phpdoc.de>, Sebastian Bergmann <sb@sebastian-bergmann.de>
  53  * @version  $Id: phplib.php,v 1.3 2003/01/04 11:54:46 mj Exp $
  54  * @package  Cache
  55  * @see      save()
  56  */
  57  class Cache_Container_phplib extends Cache_Container {
  58    
  59      /**
  60      * Name of the DB table to store caching data
  61      * 
  62      * @see  Cache_Container_file::$filename_prefix
  63      */  
  64      var $cache_table = 'cache';
  65  
  66      /**
  67      * PHPLib object
  68      * 
  69      * @var  object PEAR_DB
  70      */
  71      var $db;
  72  
  73      /**
  74      * Name of the PHPLib DB class to use
  75      * 
  76      * @var  string  
  77      * @see  $db_path, $local_path
  78      */
  79      var $db_class = '';
  80  
  81      /**
  82      * Filename of your local.inc
  83      * 
  84      * If empty, 'local.inc' is assumed.
  85      *
  86      * @var       string
  87      */
  88      var $local_file = '';
  89  
  90      /**
  91      * Include path for you local.inc
  92      *
  93      * HINT: If your're not using PHPLib's prepend.php you must 
  94      * take care that all classes (files) references by you 
  95      * local.inc are included automatically. So you might 
  96      * want to write a new local2.inc that only referrs to 
  97      * the database class (file) you're using and includes all required files.
  98      *
  99      * @var  string  path to your local.inc - make sure to add a trailing slash
 100      * @see  $local_file
 101      */
 102      var $local_path = '';
 103  
 104      /**
 105      * Creates an instance of a phplib db class to use it for storage.
 106      *
 107      * @param    mixed   If empty the object tries to used the 
 108      *                   preconfigured class variables. If given it 
 109      *                   must be an array with:
 110      *                     db_class => name of the DB class to use
 111      *                   optional:
 112      *                     db_file => filename of the DB class
 113      *                     db_path => path to the DB class
 114      *                     local_file => kind of local.inc
 115      *                     local_patk => path to the local.inc
 116      *                   see $local_path for some hints.s
 117      * @see  $local_path
 118      */
 119      function Cache_Container_phplib($options = '') {
 120          if (is_array($options))
 121              $this->setOptions($options,  array_merge($this->allowed_options, array('db_class', 'db_file', 'db_path', 'local_file', 'local_path')));
 122  
 123          if (!$this->db_class)
 124              return new Cache_Error('No database class specified.', __FILE__, __LINE__);
 125  
 126          // include the required files
 127          if ($this->db_file)
 128              include_once($this->db_path . $this->db_file);
 129  
 130          if ($this->local_file)
 131              include_once($this->local_path . $this->local_file);
 132  
 133          // create a db object 
 134          $this->db = new $this->db_class;
 135      } // end constructor
 136  
 137      function fetch($id, $group) {
 138          $query = sprintf("SELECT expires, cachedata, userdata FROM %s WHERE id = '%s' AND cachegroup = '%s'",
 139                              $this->cache_table, 
 140                              $id,
 141                              $group
 142                           );
 143          $this->db->query($query);
 144          if (!$this->db->Next_Record())
 145              return array(NULL, NULL, NULL);
 146  
 147          // last used required by the garbage collection   
 148          // WARNING: might be MySQL specific         
 149          $query = sprintf("UPDATE %s SET changed = (NOW() + 0) WHERE id = '%s' AND cachegroup = '%s'",
 150                              $this->cache_table,
 151                              $id,
 152                              $group
 153                            );
 154          $this->db->query($query);
 155          return array($this->db->f('expires'), $this->decode($this->db->f('cachedata')), $this->db->f('userdata'));
 156      } // end func fetch
 157  
 158      /**
 159      * Stores a dataset.
 160      * 
 161      * WARNING: we use the SQL command REPLACE INTO this might be 
 162      * MySQL specific. As MySQL is very popular the method should
 163      * work fine for 95% of you.
 164      */
 165      function save($id, $data, $expires, $group) {
 166          $this->flushPreload($id, $group);
 167  
 168          $query = sprintf("REPLACE INTO %s (cachedata, expires, id, cachegroup) VALUES ('%s', %d, '%s', '%s')",
 169                              $this->cache_table,
 170                              addslashes($this->encode($data)),
 171                              $this->getExpiresAbsolute($expires) ,
 172                              $id,
 173                              $group
 174                           );
 175          $this->db->query($query);
 176  
 177          return (boolean)$this->db->affected_rows(); 
 178      } // end func save
 179  
 180      function remove($id, $group) {
 181          $this->flushPreload($id, $group);
 182          $this->db->query(
 183                          sprintf("DELETE FROM %s WHERE id = '%s' AND cachegroup = '%s'",
 184                              $this->cache_table,
 185                              $id,
 186                              $group
 187                            )
 188                      );
 189  
 190          return (boolean)$this->db->affected_rows();
 191      } // end func remove
 192  
 193      function flush($group) {
 194          $this->flushPreload();
 195  
 196          if ($group) {
 197              $this->db->query(sprintf("DELETE FROM %s WHERE cachegroup = '%s'", $this->cache_table, $group));    
 198          } else {
 199              $this->db->query(sprintf("DELETE FROM %s", $this->cache_table));    
 200          }
 201  
 202          return $this->db->affected_rows();
 203      } // end func flush
 204  
 205      function idExists($id, $group) {
 206          $this->db->query(
 207                          sprintf("SELECT id FROM %s WHERE ID = '%s' AND cachegroup = '%s'", 
 208                              $this->cache_table,
 209                              $id, 
 210                              $group
 211                          )   
 212                      );
 213  
 214          return (boolean)$this->db->nf();                         
 215      } // end func isExists
 216  
 217      function garbageCollection($maxlifetime) {
 218          $this->flushPreload();
 219  
 220          $this->db->query( 
 221                          sprintf("DELETE FROM %s WHERE (expires <= %d AND expires > 0) OR changed <= (NOW() - %d)",
 222                              $this->cache_table, 
 223                              time(),
 224                              $maxlifetime
 225                          )
 226                      );
 227  
 228          //check for total size of cache
 229          $query = sprintf('select sum(length(cachedata)) as CacheSize from %s',
 230                           $this->cache_table
 231                         );
 232  
 233          $this->db->query($query);
 234          $this->db->Next_Record();
 235          $cachesize = $this->db->f('CacheSize');
 236          //if cache is to big.
 237          if ($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              $this->db->query($query);
 244  
 245              $keep_size=0;
 246              while ($keep_size < $this->lowwater && $this->db->Next_Record() )
 247              {
 248                  $keep_size += $this->db->f('size');
 249              }
 250              //delete all entries, which were changed before the "lowwwater mark"
 251              $query = sprintf('delete from %s where changed <= '.$this->db->f('changed'),
 252                                       $this->cache_table
 253                                     );
 254  
 255              $this->db->query($query);
 256          }
 257      } // end func garbageCollection
 258  }
 259  ?>