Caching with PEAR::Cache - Implementing a Framework
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The generateID method creates an md5 hash based on a given value. The hash can be used to identify the cached script results and is passed to the get and save methods when retrieving and storing the data.
<?php
$cached_id = $cache->generateID($_SERVER["PHP_SELF"]);
?> |
The save method accepts a minimum of two arguments: the id and the contents to store in the cache. However, information that changes must be regenerated and recached. A number representing the length of time for which the cached information is to be considered valid may be passed as a third argument (the time is measured in seconds). For example, the following example caches information with a shelf-life of 24 hours:
<?php
// 60 seconds × 60 minutes × 24 hours = 86400 seconds/day
$cache->save($cached_id, $content, 86400);
?> |
If the cached data's life is not set then it will never expire.
Output buffering can be used to capture a script's output for storage as it is being generated. If you're not already familiar with the output buffering functionality provided by PHP, I recommend Michael Bailey's excellent tutorial entitled PHP Output Buffering.
<?php
ob_start();
// ...PHP script which results in output goes here.
$content = ob_get_contents();
ob_end_clean();
$cache->save($cached_id, $content, 3600); //cache for 1 hour
?> |
The get method accepts an id and returns the cached content if it exists. If the content doesn't exist or has expired it will return null.
<?php
if ($content = $cache->get($cached_id))
echo $content;
?> |
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