Cache List in phpWebSite
by Matt McNaney
--------------------------

PhpWebSite has a caching class from the Pear library. It is easy to
use but be aware of the following issues:

- If the display is user specific, as in it is only seen by one user,
  caching is probably a waste of resources. Try a cache something that
  is to the benefit of several viewers.

- Be careful caching data that requires a different view depending on
  who is logged in. For example, you may have Edit links available for
  certain users. If you cache the data for a regular user, the
  administrators will not see those links.

- Don't cache individual templates. The template class takes care of that
  automatically. Do cache the results of several templates observing
  the rules above.

Cache in action
----------------------------
Here is how your code might look on a simple application:

$key = 'myModsContent';
$lifetime = 600; // number of seconds until cache refresh
                 // default is set in CACHE_LIFETIME in the
                 // config/core/config.php file
                 // 600 seconds = 10 minutes

$content = PHPWS_Cache::get($key, $lifetime);

if (empty($content)) {
  $content = getContentTheHardWay();
  PHPWS_Cache::save($key, $content);
}
 
Layout::add($content);


Pretty simple.
First, create a 'key' for your content. This should be unique so don't
use something like:

$key = 'stuff';

because there is a chance some other module developer may use it as
well.

Next, check to see a cache has been created already using the 'get'
function. If a cache has not been created or the cache has expired,
you will get NULL back.

Should you get nothing back from the 'get' function, create your
content as normal and then use the 'save' function with the 'key' you
made earlier.

Finally, display the either the cached content or the created content
using Layout.

If you need to clear the cache then use the clearCache function:
PHPWS_Cache::clearCache();

This will clear all the caches for the site so use it sparingly.

If you want to remove the cache for just your process:

PHPWS_Cache::remove($key);