Caching#

Object caching#

All functions that provide data to templates must have no side effects, as the value is cached after first access. For example, this controller method will not behave as you might imagine.

namespace App\Model;

use SilverStripe\ORM\DataObject;

class MyObject extends DataObject
{
    // ...

    private $counter = 0;

    public function getCounter()
    {
        $this->counter += 1;

        return $this->counter;
    }
}

$Counter, $Counter, $Counter

// returns 1, 1, 1

When we render $Counter to the template we would expect the value to increase and output 1, 2, 3. However, as $Counter is cached at the first access, the value of 1 is used each time it is invoked in this template.

Partial caching#

Partial caching is a feature that allows caching of a portion of a page as a single string value. For more details read its own documentation.

Example:

<% cached $CacheKey if $CacheCondition %>
    $CacheableContent
<% end_cached %>