[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  // |          Christian Stocker <chregu@phant.ch>                         |
  17  // |          Vinai Kopp <kopp@netzarbeiter.de>                           |
  18  // +----------------------------------------------------------------------+
  19  //
  20  // $Id: Output.php,v 1.6 2003/01/04 11:54:45 mj Exp $
  21  
  22  require_once  'Cache.php';
  23  
  24  /**
  25  * Class to cache the output of a script using the output buffering functions
  26  *
  27  * Simple output cache. Some pages require lots of time to compute. Caching the
  28  * output can increase the overall speed dramatically, especially if you use
  29  * a Shared Memory storage container.
  30  *
  31  * As you can see in the example the usage is extemely simple. To cache a script
  32  * simple put some few lines of code in front of your script and some at the end.
  33  * A preferrable place for this are the auto_prepend and auto_append files (=> php.ini).
  34  *
  35  * Usage example:
  36  *
  37  *  // place this somewhere in a central config file
  38  *  define(CACHE_STORAGE_CLASS, 'file');
  39  *  // file storage needs a dir to put the cache files
  40  *  define(CACHE_DIR, '/var/tmp/');
  41  *
  42  *  // get a cache object
  43  *  $cache = new Cache_Output(CACHE_STORAGE_CLASS, array('cache_dir' => CACHE_DIR));
  44  *
  45  *  // compute the unique handle.
  46  *  // if your script depends on Cookie and HTTP Post data as well
  47  *  // you should use:
  48  *  // $cache_handle = array(
  49  *  //                       'file' => $REQUEST_URI,
  50  *  //                       'post' => $HTTP_POST_VARS,
  51  *  //                       'cookie'  => $HTTP_COOKIE_VARS
  52  *  //                    );
  53  *  // But be warned, using all GET or POST Variables as a seed
  54  *  // can be used for a DOS attack. Calling http://www.example.com/example.php?whatever
  55  *  // where whatever is a random text might be used to flood your cache.
  56  *  $cache_handle = $cache->generateID($REQUEST_URI);
  57  *
  58  *  // now the magic happens: if cached call die()
  59  *  // to end the time consumptiong script script execution and use the cached value!
  60  *  if ($content = $cache->start($cache_handle)) {
  61  *     print $content;
  62  *     print '<p>Cache hit</p>';
  63  *     die();
  64  *  }
  65  *
  66  *  // time consumption script goes here.
  67  *
  68  *  // store the output of the cache into the cache and print the output.
  69  *  print $cache->end();
  70  *  print "<p>Cache miss, stored using the ID '$id'.</p>";
  71  *
  72  *  If you do not want to cache a whole page - no problem:
  73  *
  74  *  if (!($content = $cache->start($cache_handle))) {
  75  *     // do the computation here
  76  *     print $cache->end()
  77  *  } else {
  78  *     print $content;
  79  *  }
  80  *
  81  *  If you need an example script check the (auto_)prepend and (auto_)append
  82  *  files of my homepage:
  83  *
  84  *    http://www.ulf-wendel.de/php/show_source.php?file=prepend
  85  *    http://www.ulf-wendel.de/php/show_source.php?file=append
  86  *
  87  *  Don't know how to use it or you need profiling informations?`
  88  *  Ask Christian he was patient with me and he'll be so with your questions ;).
  89  *
  90  *  Have fun!
  91  *
  92  * @authors  Ulf Wendel <ulf.wendel@phpdoc.de>
  93  * @version  $ID: $
  94  * @package  Cache
  95  * @access   public
  96  */
  97  class Cache_Output extends Cache {
  98  
  99      /**
 100      * ID passed to start()
 101      *
 102      * @var  string
 103      * @see  start(), end()
 104      */
 105      var $output_id = '';
 106  
 107      /**
 108      * Group passed to start()
 109      *
 110      * @var  string
 111      * @see  start(), end()
 112      */
 113      var $output_group = '';
 114  
 115      /**
 116      * PEAR-Deconstructor
 117      * Call deconstructor of parent
 118      */
 119      function _Cache_Output()
 120      {
 121                  $this->_Cache();
 122      }
 123  
 124      /**
 125      * starts the output buffering and returns an empty string or returns the cached output from the cache.
 126      *
 127      * @param    string  dataset ID
 128      * @param    string  cache group
 129      * @return   string
 130      * @access   public
 131      */
 132      function start($id, $group = 'default') {
 133          if (!$this->caching)
 134              return '';
 135  
 136          // this is already cached return it from the cache so that the user
 137          // can use the cache content and stop script execution
 138          if ($content = $this->get($id, $group))
 139              return $content;
 140  
 141          // remember some data to be able to fill the cache on calling end()
 142          $this->output_id = $id;
 143          $this->output_group = $group;
 144  
 145          // WARNING: we need the output buffer - possible clashes
 146          ob_start();
 147          ob_implicit_flush(false);
 148  
 149          return '';
 150      } // end func start
 151  
 152      /*
 153      * Stores the content of the output buffer into the cache and returns the content.
 154      *
 155      * @param    mixed   lifetime of the cached data in seconds - 0 for endless. More formats available. see Container::getExpiresAbsolute()
 156      * @param    string  additional userdefined data
 157      * @return   string  cached output
 158      * @access   public
 159      * @see      endPrint(), endGet(), Container::getExpiresAbsolute()
 160      */
 161      function end($expire = 0, $userdata = '') {
 162          $content = ob_get_contents();
 163          ob_end_clean();
 164  
 165          // store in the cache
 166          if ($this->caching)
 167              $this->container->save($this->output_id, $content, $expire, $this->output_group, $userdata);
 168  
 169          return $content;
 170      } // end func end()
 171  
 172      /**
 173      * Stores the content of the output buffer into the cache and prints the content.
 174      *
 175      * @brother  end()
 176      */
 177      function endPrint($expire = 0, $userdata = '') {
 178          $this->printContent($this->end($expire, $userdata));
 179      } // end func endPrint
 180  
 181      /**
 182      * Sends the data to the user.
 183      * This is for compatibility with OutputCompression
 184      * 
 185      * @param    string
 186      * @access   public
 187      */    
 188      function printContent($content = '') {
 189          if ('' == $content)
 190              $content = &$this->container->cachedata;
 191              
 192          print $content;
 193      }
 194      /**
 195      * Returns the content of the output buffer but does not store it into the cache.
 196      *
 197      * Use this method if the content of your script is markup (XML)
 198      * that has to be parsed/converted (XSLT) before you can output
 199      * and store it into the cache using save().
 200      *
 201      * @return   string
 202      * @access   public
 203      * @see      endPrint(), end()
 204      */
 205      function endGet() {
 206          $content = ob_get_contents();
 207          ob_end_clean();
 208  
 209          $this->output_id = '';
 210          $this->output_group = '';
 211  
 212          return $content;
 213      } // end func endGet
 214  } // end class output
 215  ?>