application/CachedPage.php

   1 <?php
   2 /**
   3  * Simple cache system, mainly for the RSS/ATOM feeds
   4  */
   5 class CachedPage
   6 {
   7     // Directory containing page caches
   8     private $cacheDir;
   9
  10     // Full URL of the page to cache -typically the value returned by pageUrl()
  11     private $url;
  12
  13     // Should this URL be cached (boolean)?
  14     private $shouldBeCached;
  15
  16     // Name of the cache file for this URL
  17     private $filename;
  18
  19     /**
  20      * Creates a new CachedPage
  21      *
  22      * @param string $cacheDir       page cache directory
  23      * @param string $url            page URL
  24      * @param bool   $shouldBeCached whether this page needs to be cached
  25      */
  26     public function __construct($cacheDir, $url, $shouldBeCached)
  27     {
  28         // TODO: check write access to the cache directory
  29         $this->cacheDir = $cacheDir;
  30         $this->url = $url;
  31         $this->filename = $this->cacheDir.'/'.sha1($url).'.cache';
  32         $this->shouldBeCached = $shouldBeCached;
  33     }
  34
  35     /**
  36      * Returns the cached version of a page, if it exists and should be cached
  37      *
  38      * @return string a cached version of the page if it exists, null otherwise
  39      */
  40     public function cachedVersion()
  41     {
  42         if (!$this->shouldBeCached) {
  43             return null;
  44         }
  45         if (is_file($this->filename)) {
  46             return file_get_contents($this->filename);
  47         }
  48         return null;
  49     }
  50
  51     /**
  52      * Puts a page in the cache
  53      *
  54      * @param string $pageContent XML content to cache
  55      */
  56     public function cache($pageContent)
  57     {
  58         if (!$this->shouldBeCached) {
  59             return;
  60         }
  61         file_put_contents($this->filename, $pageContent);
  62     }
  63 }