classes/kohana/fragment.php

   1 <?php defined('SYSPATH') or die('No direct script access.');
   2 /**
   3  * View fragment caching. This is primarily used to cache small parts of a view
   4  * that rarely change. For instance, you may want to cache the footer of your
   5  * template because it has very little dynamic content. Or you could cache a
   6  * user profile page and delete the fragment when the user updates.
   7  *
   8  * For obvious reasons, fragment caching should not be applied to any
   9  * content that contains forms.
  10  *
  11  * [!!] Multiple language (I18n) support was added in v3.0.4.
  12  *
  13  * @package    Kohana
  14  * @category   Helpers
  15  * @author     Kohana Team
  16  * @copyright  (c) 2009-2010 Kohana Team
  17  * @license    http://kohanaframework.org/license
  18  * @uses       Kohana::cache
  19  */
  20 class Kohana_Fragment {
  21
  22         /**
  23          * @var  integer  default number of seconds to cache for
  24          */
  25         public static $lifetime = 30;
  26
  27         /**
  28          * @var  boolean  use multilingual fragment support?
  29          */
  30         public static $i18n = FALSE;
  31
  32         // List of buffer => cache key
  33         protected static $_caches = array();
  34
  35         /**
  36          * Generate the cache key name for a fragment.
  37          *
  38          *     $key = Fragment::_cache_key('footer', TRUE);
  39          *
  40          * @param   string   fragment name
  41          * @param   boolean  multilingual fragment support
  42          * @return  string
  43          * @uses    I18n::lang
  44          * @since   3.0.4
  45          */
  46         protected static function _cache_key($name, $i18n = NULL)
  47         {
  48                 if ($i18n === NULL)
  49                 {
  50                         // Use the default setting
  51                         $i18n = Fragment::$i18n;
  52                 }
  53
  54                 // Language prefix for cache key
  55                 $i18n = ($i18n === TRUE) ? I18n::lang() : '';
  56
  57                 // Note: $i18n and $name need to be delimited to prevent naming collisions
  58                 return 'Fragment::cache('.$i18n.'+'.$name.')';
  59         }
  60
  61         /**
  62          * Load a fragment from cache and display it. Multiple fragments can
  63          * be nested with different life times.
  64          *
  65          *     if ( ! Fragment::load('footer')) {
  66          *         // Anything that is echo'ed here will be saved
  67          *         Fragment::save();
  68          *     }
  69          *
  70          * @param   string   fragment name
  71          * @param   integer  fragment cache lifetime
  72          * @param   boolean  multilingual fragment support
  73          * @return  boolean
  74          */
  75         public static function load($name, $lifetime = NULL, $i18n = NULL)
  76         {
  77                 // Set the cache lifetime
  78                 $lifetime = ($lifetime === NULL) ? Fragment::$lifetime : (int) $lifetime;
  79
  80                 // Get the cache key name
  81                 $cache_key = Fragment::_cache_key($name, $i18n);
  82
  83                 if ($fragment = Kohana::cache($cache_key, NULL, $lifetime))
  84                 {
  85                         // Display the cached fragment now
  86                         echo $fragment;
  87
  88                         return TRUE;
  89                 }
  90                 else
  91                 {
  92                         // Start the output buffer
  93                         ob_start();
  94
  95                         // Store the cache key by the buffer level
  96                         Fragment::$_caches[ob_get_level()] = $cache_key;
  97
  98                         return FALSE;
  99                 }
 100         }
 101
 102         /**
 103          * Saves the currently open fragment in the cache.
 104          *
 105          *     Fragment::save();
 106          *
 107          * @return  void
 108          */
 109         public static function save()
 110         {
 111                 // Get the buffer level
 112                 $level = ob_get_level();
 113
 114                 if (isset(Fragment::$_caches[$level]))
 115                 {
 116                         // Get the cache key based on the level
 117                         $cache_key = Fragment::$_caches[$level];
 118
 119                         // Delete the cache key, we don't need it anymore
 120                         unset(Fragment::$_caches[$level]);
 121
 122                         // Get the output buffer and display it at the same time
 123                         $fragment = ob_get_flush();
 124
 125                         // Cache the fragment
 126                         Kohana::cache($cache_key, $fragment);
 127                 }
 128         }
 129
 130         /**
 131          * Delete a cached fragment.
 132          *
 133          *     Fragment::delete($key);
 134          *
 135          * @param   string   fragment name
 136          * @param   boolean  multilingual fragment support
 137          * @return  void
 138          */
 139         public static function delete($name, $i18n = NULL)
 140         {
 141                 // Invalid the cache
 142                 Kohana::cache(Fragment::_cache_key($name, $i18n), NULL, -3600);
 143         }
 144
 145 } // End Fragment