Elefant provides a caching layer that mimics the Memcache API with some additional conveniences, and provides the following storage options:
The filesystem is the default storage engine.
The cache is available to handlers via the $cache object which is provided by the
Controller when it calls your handler script.
Here is the most common usage pattern:
<?php
$res = $cache->get ('my_list');
if (! $res) {
$res = DB::fetch ('select * from foo');
$cache->set ('my_list', $res, 3600); // 1 hour
}
?>
Alternately, you can implement caching via a callback function, which can help separate your caching logic from your application logic:
<?php
$res = $cache->cache ('my_list', 3600, function () {
return DB::fetch ('select * from foo');
});
?>
The returned data will be cached for you, and the function will only be called when the data isn't found in the cache, or the cached data has expired.
Elefant supports automatic caching of a handler's output with a simple one-liner. To cache the output indefinitely:
<?php
$this->cache = true;
?>
To cache for 5 minutes:
<?php
$this->cache = 300;
?>
Handlers are cached with a key of the form _c_myapp_somehandler where _c_ is
added as a prefix, and slashes in the handler path are converted to underscores.
You can use this to delete a cache entry for an indefinitely cached handler like this:
<?php
$cache->delete ('_c_myapp_somehandler');
?>
It's important to note the limitations of handler caching, namely that any headers
or scripts that have been added via $this->header() or $this->add_script() will
not be cached, so make sure to only cache handlers that don't make use of these.
Elefant provides a command line option to clear your cache folder of not just its cache data but also its compiled templates and site navigation:
./elefant clear-cache
This is a safer alternative to rm -rf cache/* since it is careful not to erase
additional data other apps may be storing in the cache folder, such as image
thumbnails.
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