silverstripe-framework/docs/en/reference/flushable.md
Sean Harvey 2b316e79e5 NEW Provide a consistent way of triggering flush
Provides an interface for classes to implement their own flush()
functionality. This function gets called early in a request on
all implementations of Flushable when flush=1|all is requested in the
URL.

This fix came out of an issue where Requirements combined files were not
being cleaned up after dev/build?flush=1, due to the fact that flush
would only occur when you called it while on a page that used those
combined files, but not in any other contexts. This will now call flush
on any implementors of Flushable regardless of the context of where
flush was called.
2014-08-22 09:24:27 +12:00

1.5 KiB

Flushable

Introduction

Allows a class to define it's own flush functionality, which is triggered when flush=1 is requested in the URL.

[api:FlushRequestFilter] is run before a request is made, calling flush() statically on all implementors of [api:Flushable].

Usage

To use this API, you need to make your class implement [api:Flushable], and define a flush() static function, this defines the actions that need to be executed on a flush request.

Using with SS_Cache

This example uses [api:SS_Cache] in some custom code, and the same cache is cleaned on flush:

:::php
<?php
class MyClass extends DataObject implements Flushable {

	public static function flush() {
		SS_Cache::factory('mycache')->clean(Zend_Cache::CLEANING_MODE_ALL);
	}

	public function MyCachedContent() {
		$cache = SS_Cache::factory('mycache')
		$something = $cache->get('mykey');
		if(!$something) {
			$something = 'value to be cached';
			$cache->save($something);
		}
		return $something;
	}

}

Using with filesystem

Another example, some temporary files are created in a directory in assets, and are deleted on flush. This would be useful in an example like GD or Imagick generating resampled images, but we want to delete any cached images on flush so they are re-created on demand.

:::php
<?php
class MyClass extends DataObject implements Flushable {

	public static function flush() {
		foreach(glob(ASSETS_PATH . '/_tempfiles/*.jpg') as $file) {
			unlink($file);
		}
	}

}