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   1  <?php
   2  
   3  /** This file is part of KCFinder project
   4    *
   5    *      @desc HTTP cache helper class
   6    *   @package KCFinder
   7    *   @version 2.21
   8    *    @author Pavel Tzonkov <[email protected]>
   9    * @copyright 2010 KCFinder Project
  10    *   @license http://www.opensource.org/licenses/gpl-2.0.php GPLv2
  11    *   @license http://www.opensource.org/licenses/lgpl-2.1.php LGPLv2
  12    *      @link http://kcfinder.sunhater.com
  13    */
  14  
  15  class httpCache {
  16      const DEFAULT_TYPE = "text/html";
  17      const DEFAULT_EXPIRE = 604800; // in seconds
  18  
  19    /** Cache a file. The $type parameter might define the MIME type of the file
  20      * or path to magic file to autodetect the MIME type. If you skip $type
  21      * parameter the method will try with the default magic file. Autodetection
  22      * of MIME type requires Fileinfo PHP extension used in file::getMimeType()
  23      * @param string $file
  24      * @param string $type
  25      * @param integer $expire
  26      * @param array $headers */
  27  
  28      static function file($file, $type=null, $expire=null, array $headers=null) {
  29          $mtime = @filemtime($file);
  30          if ($mtime !== false) self::checkMTime($mtime);
  31  
  32          if ($type === null) {
  33              $magic = ((substr($type, 0, 1) == "/") || preg_match('/^[a-z]\:/i', $type))
  34                  ? $type : null;
  35              $type = file::getMimeType($file, $magic);
  36              if (!$type) $type = null;
  37          }
  38  
  39          self::content(@file_get_contents($file), $mtime, $type, $expire, $headers, false);
  40      }
  41  
  42    /** Cache the given $content with $mtime modification time.
  43      * @param binary $content
  44      * @param integer $mtime
  45      * @param string $type
  46      * @param integer $expire
  47      * @param array $headers
  48      * @param bool $checkMTime */
  49  
  50      static function content($content, $mtime, $type=null, $expire=null, array $headers=null, $checkMTime=true) {
  51          if ($checkMTime) self::checkMTime($mtime);
  52          if ($type === null) $type = self::DEFAULT_TYPE;
  53          if ($expire === null) $expire = self::DEFAULT_EXPIRE;
  54          $size = strlen($content);
  55          $expires = gmdate("D, d M Y H:i:s", time() + $expire) . " GMT";
  56          header("Content-Type: $type");
  57          header("Expires: $expires");
  58          header("Cache-Control: max-age=$expire");
  59          header("Pragma: !invalid");
  60          header("Content-Length: $size");
  61          if ($headers !== null) foreach ($headers as $header) header($header);
  62          echo $content;
  63      }
  64  
  65    /** Check if given modification time is newer than client-side one. If not,
  66      * the method will tell the client to get the content from its own cache.
  67      * Afterwards the script process will be terminated. This feature requires
  68      * the PHP to be configured as Apache module.
  69      * @param integer $mtime */
  70  
  71      static function checkMTime($mtime) {
  72          header("Last-Modified: " . gmdate("D, d M Y H:i:s", $mtime) . " GMT");
  73  
  74          $headers = function_exists("getallheaders")
  75              ? getallheaders()
  76              : (function_exists("apache_request_headers")
  77                  ? apache_request_headers()
  78                  : false);
  79  
  80          if (is_array($headers) && isset($headers['If-Modified-Since'])) {
  81              $client_mtime = explode(';', $headers['If-Modified-Since']);
  82              $client_mtime = strtotime($client_mtime[0]);
  83              if ($client_mtime >= $mtime) {
  84                  header('HTTP/1.1 304 Not Modified');
  85                  die;
  86              }
  87          }
  88      }
  89  }
  90  
  91  ?>