Cache Extras

This add-on adds additional cache-related methods to the SimplePie object such as cache file name, cache timestamp, and cache time remaining.

1. Create a new file called simplepie_cache_extras.inc and place it in the same directory as your simplepie.inc file.
2. On the SimplePie-enabled page you want to use this extension on, make sure you include it in the same way that you include simplepie.inc.

<?php
class SimplePie_Cache_Extras extends SimplePie
{
	function get_cache_object()
	{
		$cache =& new $this->cache_class($this->cache_location, call_user_func($this->cache_name_function, $this->feed_url), 'spc');
		return $cache;
	}
 
	function get_cache_filename()
	{
		$cache = $this->get_cache_object();
		return $cache->name;
	}
 
	function get_cache_timestamp()
	{
		$cache = $this->get_cache_object();
		return $cache->mtime();
	}
 
	function get_cache_time_remaining($format = false)
	{
		$cache = $this->get_cache_object();
		$remaining = ($cache->mtime() + $this->cache_duration) - time();
 
		if ($format)
		{
			return SimplePie_Misc::time_hms($remaining);
		}
		else
		{
			return $remaining;
		}
	}
}
?>

• get_cache_object()
  Returns the SimplePie_Cache object that SimplePie is using. This is used by the other methods to return their data.
• get_cache_filename()
  Returns the path and filename of the cache file for this feed.
• get_cache_timestamp()
  Returns a UNIX timestamp for the time when the feed was cached.
• get_cache_time_remaining()
  Returns the remaining time (in seconds) until the cache is considered stale, and SimplePie will re-check the feed for freshness. Optionally, you can pass true as the parameter, and it will return the remaining time in a hh:mm:ss format instead.

<?php
require_once('simplepie.inc');
require_once('simplepie_cache_extras.inc');
 
// Instead of a new SimplePie(), we'll do a new SimplePie_Cache_Extras() since we extended the SimplePie class.
$feed = new SimplePie_Cache_Extras('http://digg.com/rss/index.xml');
$feed->handle_content_type();
 
// Let's display the filename of the cached feed.
echo 'Cached file name: ' . $feed->get_cache_filename() . '<br />';
 
// When was this cache file created?
echo 'File was cached at: ' . $feed->get_cache_timestamp() . ' (' . date('j F Y, g:i a', $feed->get_cache_timestamp()) . ')<br />';
 
// How long until the cache expires?
echo 'Time remaining until next cache check: ' . $feed->get_cache_time_remaining() . ' seconds (' . $feed->get_cache_time_remaining(true) . ' hh:mm:ss)<br />';
 
echo '<hr />';
 
foreach ($feed->get_items() as $item)
{
	echo '<a href="' . $item->get_permalink() . '">' . $item->get_title() . '</a><br />';
}
?>

For anyone who can't get this to work I managed to get it to work by doing the following below. I commented out the main line in the get_cache_object() function and added in the line as shown below which I found in the main simplepie.inc file.

This worked right away and allowed all the cache functions to start working. Hopefully I've not done anything silly here though?

<?php
class SimplePie_Cache_Extras extends SimplePie
{
	function get_cache_object()
	{
//		$cache =& new $this->cache_class($this->cache_location, call_user_func($this->cache_name_function, $this->feed_url), 'spc');
		$cache = call_user_func(array($this->cache_class, 'create'), $this->cache_location, call_user_func($this->cache_name_function, $this->feed_url), 'spc');
		return $cache;
	}
 
	function get_cache_filename()
	{
		$cache = $this->get_cache_object();
		return $cache->name;
	}
 
	function get_cache_timestamp()
	{
		$cache = $this->get_cache_object();
		return $cache->mtime();
	}
 
	function get_cache_time_remaining($format = false)
	{
		$cache = $this->get_cache_object();
		$remaining = ($cache->mtime() + $this->cache_duration) - time();
 
		if ($format)
		{
			return SimplePie_Misc::time_hms($remaining);
		}
		else
		{
			return $remaining;
		}
	}
}
?>