WP REST API Cache

Enable caching for the WordPress REST API and the increase speed of your application.

• Installation
• Actions
• How to use actions
• Filters
• How to use filters

Installation

1. Copy the wp-rest-api-cache folder into your wp-content/plugins folder
2. Activate the WP REST API Cache plugin via the plugin admin page

Actions

Action	Argument(s)
wp_rest_cache_skipped	mixed $result WP_REST_Server $server WP_REST_Request $request
rest_cache_request_flush_cache	string $message string $type WP_User $user

How to use actions

add_action( 'wp_rest_cache_skipped', function( $result, \WP_REST_Server $server, \WP_REST_Request $request ) {
	// Do something here, like create a log entry using Wonolog.
	do_action( 'wonolog.log', new Log(
		sprintf( 'The `%s` REST route cache was skipped.', $request->get_route() ),
		\Monolog\Logger::NOTICE,
		\Inpsyde\Wonolog\Channels::DEBUG,
		[
			$result,
			$server,
			$request,
		]
	) );
}, 10, 3 );

add_action( 'rest_cache_request_flush_cache', function( $message, $type, WP_User $user ) {
	// Do something here, like create a log entry using Wonolog.
	do_action( 'wonolog.log', new Log(
		sprintf( 'The `%s` user just flushed the object cache.', $user->user_login ),
		\Monolog\Monolog\Logger::NOTICE,
		\Inpsyde\Wonolog\Channels::DEBUG,
		[
			$message,
			$type,
			$user
		]
	) );
}, 10, 3 );

Filters

Filter	Argument(s)
rest_cache_headers	array $headers string $request_uri WP_REST_Server $server WP_REST_Request $request WP_REST_Response $response (rest_post_dispatch only)
rest_cache_skip	boolean $skip ( default: WP_DEBUG ) string $request_uri WP_REST_Server $server WP_REST_Request $request
rest_cache_key	string $request_uri WP_REST_Server $server WP_REST_Request $request
rest_cache_group	string $cache_group
rest_cache_timeout	int $timeout int $length int $period
rest_cache_update_options	array $options
rest_cache_get_options	array $options
rest_cache_show_admin	boolean $show
rest_cache_show_admin_menu	boolean $show
rest_cache_show_admin_bar_menu	boolean $show
allowed_rest_cache_status	array $status HTTP Header statuses (defaults to array( 200 )
rest_cache_control_no_cache_value	array $cache_control Cache-Control header to not cache request. (defaults to array( 'private', 'no-cache', 'no-store', 'must-revalidate' )

How to use filters

• sending headers

add_filter( 'rest_cache_headers', function( $headers ) {
	$headers['Cache-Control'] = 'public, max-age=3600';
	
	return $headers;
} );

• changing the cache timeout

add_filter( 'rest_cache_timeout', function() {
	// https://codex.wordpress.org/Transients_API#Using_Time_Constants
	return 15 * DAY_IN_SECONDS;
} );

or

add_filter( 'rest_cache_get_options', function( $options ) {
	if ( ! isset( $options['timeout'] ) ) {
		$options['timeout'] = array();
	}

	// https://codex.wordpress.org/Transients_API#Using_Time_Constants
	$options['timeout']['length'] = 15;
	$options['timeout']['period'] = DAY_IN_SECONDS;
	
	return $options;
} );

• skipping cache

add_filter( 'rest_cache_skip', function( $skip, $request_uri ) {
	if ( ! $skip && false !== stripos( 'wp-json/acf/v2', $request_uri ) ) {
		return true;
	}

	return $skip;
}, 10, 2 );

If rest_cache_skip is true, this action is called: wp_rest_cache_skipped.

add_action( 'wp_rest_cache_skipped', function( $result, WP_REST_Server $server, WP_REST_Request $request ) {
	// Do something here
}, 10, 3 );

• deleting cache

Soft delete: Append rest_cache_delete to your query param; &rest_cache_delete=1.
soft delete will delete the cache after the current request completes (on WordPress shutdown).

Hard delete: Append rest_cache_delete && rest_force_delete to your query param; &rest_cache_delete=1&rest_force_delete=1.
hard delete will delete the cache before the request, forcing it to repopulate.

• show / hide admin links

• empty ALL cache on post-save this is not ideal

You can use WordPress' default filter "save_post" if you would like to empty ALL the cache on save of a post, page or custom post type.

add_action( 'save_post', function( $post_id ) {
  if ( class_exists( 'WP_REST_Cache' ) ) {
    WP_REST_Cache::flush_all_cache();
  }
} );

• clear endpoint cache on transition

You can use WordPress' default filter "save_post" if you would like to empty ALL the cache on save of a post, page or custom post type. THIS IS A WORK IN PROGRESS.

add_action( 'transition_post_status', function( $new_status, $old_status, WP_Post $post ) {
  if ( 'publish' === $new_status && 'publish' !== $old_status ) {
    if ( class_exists( 'WP_REST_Cache' ) ) {
        //$url = get_permalink( $post->ID );
        //$key = WP_REST_Cache::get_cache_key();
        //WP_REST_Cache::delete_cache_by_key( $key );
    }
  }
} );