database/DB_cache.php

   1 <?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');\r
   2 /**\r
   3  * CodeIgniter\r
   4  *\r
   5  * An open source application development framework for PHP 4.3.2 or newer\r
   6  *\r
   7  * @package             CodeIgniter\r
   8  * @author              ExpressionEngine Dev Team\r
   9  * @copyright   Copyright (c) 2008, EllisLab, Inc.\r
  10  * @license             http://codeigniter.com/user_guide/license.html\r
  11  * @link                http://codeigniter.com\r
  12  * @since               Version 1.0\r
  13  * @filesource\r
  14  */\r
  15 \r
  16 // ------------------------------------------------------------------------\r
  17 \r
  18 /**\r
  19  * Database Cache Class\r
  20  *\r
  21  * @category    Database\r
  22  * @author              ExpressionEngine Dev Team\r
  23  * @link                http://codeigniter.com/user_guide/database/\r
  24  */\r
  25 class CI_DB_Cache {\r
  26 \r
  27         var $CI;\r
  28         var $db;        // allows passing of db object so that multiple database connections and returned db objects can be supported\r
  29 \r
  30         /**\r
  31          * Constructor\r
  32          *\r
  33          * Grabs the CI super object instance so we can access it.\r
  34          *\r
  35          */     \r
  36         function CI_DB_Cache(&$db)\r
  37         {\r
  38                 // Assign the main CI object to $this->CI\r
  39                 // and load the file helper since we use it a lot\r
  40                 $this->CI =& get_instance();\r
  41                 $this->db =& $db;\r
  42                 $this->CI->load->helper('file');        \r
  43         }\r
  44 \r
  45         // --------------------------------------------------------------------\r
  46 \r
  47         /**\r
  48          * Set Cache Directory Path\r
  49          *\r
  50          * @access      public\r
  51          * @param       string  the path to the cache directory\r
  52          * @return      bool\r
  53          */             \r
  54         function check_path($path = '')\r
  55         {\r
  56                 if ($path == '')\r
  57                 {\r
  58                         if ($this->db->cachedir == '')\r
  59                         {\r
  60                                 return $this->db->cache_off();\r
  61                         }\r
  62                 \r
  63                         $path = $this->db->cachedir;\r
  64                 }\r
  65         \r
  66                 // Add a trailing slash to the path if needed\r
  67                 $path = preg_replace("/(.+?)\/*$/", "\\1/",  $path);\r
  68 \r
  69                 if ( ! is_dir($path) OR ! is_really_writable($path))\r
  70                 {\r
  71                         // If the path is wrong we'll turn off caching\r
  72                         return $this->db->cache_off();\r
  73                 }\r
  74                 \r
  75                 $this->db->cachedir = $path;\r
  76                 return TRUE;\r
  77         }\r
  78         \r
  79         // --------------------------------------------------------------------\r
  80 \r
  81         /**\r
  82          * Retrieve a cached query\r
  83          *\r
  84          * The URI being requested will become the name of the cache sub-folder.\r
  85          * An MD5 hash of the SQL statement will become the cache file name\r
  86          *\r
  87          * @access      public\r
  88          * @return      string\r
  89          */\r
  90         function read($sql)\r
  91         {\r
  92                 if ( ! $this->check_path())\r
  93                 {\r
  94                         return $this->db->cache_off();\r
  95                 }\r
  96 \r
  97                 $segment_one = ($this->CI->uri->segment(1) == FALSE) ? 'default' : $this->CI->uri->segment(1);\r
  98                 \r
  99                 $segment_two = ($this->CI->uri->segment(2) == FALSE) ? 'index' : $this->CI->uri->segment(2);\r
 100         \r
 101                 $filepath = $this->db->cachedir.$segment_one.'+'.$segment_two.'/'.md5($sql);            \r
 102                 \r
 103                 if (FALSE === ($cachedata = read_file($filepath)))\r
 104                 {       \r
 105                         return FALSE;\r
 106                 }\r
 107                 \r
 108                 return unserialize($cachedata);                 \r
 109         }       \r
 110 \r
 111         // --------------------------------------------------------------------\r
 112 \r
 113         /**\r
 114          * Write a query to a cache file\r
 115          *\r
 116          * @access      public\r
 117          * @return      bool\r
 118          */\r
 119         function write($sql, $object)\r
 120         {\r
 121                 if ( ! $this->check_path())\r
 122                 {\r
 123                         return $this->db->cache_off();\r
 124                 }\r
 125 \r
 126                 $segment_one = ($this->CI->uri->segment(1) == FALSE) ? 'default' : $this->CI->uri->segment(1);\r
 127                 \r
 128                 $segment_two = ($this->CI->uri->segment(2) == FALSE) ? 'index' : $this->CI->uri->segment(2);\r
 129         \r
 130                 $dir_path = $this->db->cachedir.$segment_one.'+'.$segment_two.'/';\r
 131                 \r
 132                 $filename = md5($sql);\r
 133         \r
 134                 if ( ! @is_dir($dir_path))\r
 135                 {\r
 136                         if ( ! @mkdir($dir_path, DIR_WRITE_MODE))\r
 137                         {\r
 138                                 return FALSE;\r
 139                         }\r
 140                         \r
 141                         @chmod($dir_path, DIR_WRITE_MODE);                      \r
 142                 }\r
 143                 \r
 144                 if (write_file($dir_path.$filename, serialize($object)) === FALSE)\r
 145                 {\r
 146                         return FALSE;\r
 147                 }\r
 148                 \r
 149                 @chmod($dir_path.$filename, DIR_WRITE_MODE);\r
 150                 return TRUE;\r
 151         }\r
 152 \r
 153         // --------------------------------------------------------------------\r
 154 \r
 155         /**\r
 156          * Delete cache files within a particular directory\r
 157          *\r
 158          * @access      public\r
 159          * @return      bool\r
 160          */\r
 161         function delete($segment_one = '', $segment_two = '')\r
 162         {       \r
 163                 if ($segment_one == '')\r
 164                 {\r
 165                         $segment_one  = ($this->CI->uri->segment(1) == FALSE) ? 'default' : $this->CI->uri->segment(1);\r
 166                 }\r
 167                 \r
 168                 if ($segment_two == '')\r
 169                 {\r
 170                         $segment_two = ($this->CI->uri->segment(2) == FALSE) ? 'index' : $this->CI->uri->segment(2);\r
 171                 }\r
 172                 \r
 173                 $dir_path = $this->db->cachedir.$segment_one.'+'.$segment_two.'/';\r
 174                 \r
 175                 delete_files($dir_path, TRUE);\r
 176         }\r
 177 \r
 178         // --------------------------------------------------------------------\r
 179 \r
 180         /**\r
 181          * Delete all existing cache files\r
 182          *\r
 183          * @access      public\r
 184          * @return      bool\r
 185          */\r
 186         function delete_all()\r
 187         {\r
 188                 delete_files($this->db->cachedir, TRUE);\r
 189         }\r
 190 \r
 191 }\r
 192 \r
 193 \r
 194 /* End of file DB_cache.php */\r
 195 /* Location: ./system/database/DB_cache.php */