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Where does WordPress default SimplePie save cache data? I could only find relevant info about cache durations but not the location. SimplePie has a method called set_cache_location() but I cannot find it being used in WordPress.

I'm writing a plugin and if a cache folder is available already by default, I'd like to use it rather than creating for my plugin.

Does anybody know it?

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up vote 1 down vote accepted

In WordPress, the WP_Feed_Cache class uses the WP_Feed_Cache_Transient class to store the results into a transient.

So, short answer, either in the database or in the Object Cache if you have a persistent object cache stored.

If you need to cache something for a period of time, use a transient.


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Thanks for the info. I looked into the source in feed.php and there are lines $feed->set_cache_class('WP_Feed_Cache'); $feed->set_file_class('WP_SimplePie_File'); It looks these are the ones setting a transient. I have a custom class which extends SimplePie which WordPress includes. In that case, can I just use these methods and simply pass the words, WP_Feed_Cache and WP_SimplePie_File? – Teno Aug 30 '12 at 18:30
You should use set_transient described in the link above. – Wyck Aug 30 '12 at 18:49
Do you mean I should use set_transient() separately from SimplePie? Or are you suggesting that I should implement the function into the custom extended class? – Teno Aug 30 '12 at 18:57
As I test with my custom class extending the default WordPress SimplePie class, in addition to the above methods, set_cache_class('WP_Feed_Cache') and set_file_class('WP_SimplePie_File'), set_cache_duration(apply_filters('wp_feed_cache_transient_lifetime', $cacheduration, $url)) works fine without errors. – Teno Aug 30 '12 at 19:23
If you're using it in your plugin, you do want to use set_cache_class() and set_file_class() there, not set_transient – Ryan McCue Aug 31 '12 at 1:26

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