How to properly handle nonce caching?

[LukaszJaro]

Hi,

I have a contact form that uses a nonce, when the nonce expires it stays in the cache unless page reload occurs. Since the nonce value is stale and no longer valid, it causes the form to fail. Is there a filter for specific nonce exclusion?

[westonruter]

That's a good question. What caching strategy are you using for pages?

[LukaszJaro]

STRATEGY_STALE_WHILE_REVALIDATE

add_filter(
	'wp_service_worker_navigation_caching_strategy',
	function() {
		return WP_Service_Worker_Caching_Routes::STRATEGY_STALE_WHILE_REVALIDATE;
	}
);

add_filter(
	'wp_service_worker_navigation_caching_strategy_args',
	function( $args ) {
		$args['cacheName']                           = 'pages';
		$args['plugins']['expiration']['maxEntries'] = 20;
		return $args;
	}
);

[westonruter]

OK, thank you. Yes, I can definitely see how this would be problem. One possibility would be to make pages expire within the lifespan of the nonce. This can be done using maxAgeSeconds, for example:

add_filter(
	'wp_service_worker_navigation_caching_strategy_args',
	function( $args ) {
		$args['cacheName']                           = 'pages';
		$args['plugins']['expiration']['maxEntries'] = 20;

		// 👇 New!
		/** This filter is documented in wp-includes/pluggable.php */
		$max_age_seconds = apply_filters( 'nonce_life', DAY_IN_SECONDS );
		$args['plugins']['expiration']['maxAgeSeconds'] = $max_age_seconds;

		return $args;
	}
);

The value and applied filter there is copied from wp_nonce_tick() in core.

[LukaszJaro]

Brilliant, thanks! I'm going to give this a shot

[LukaszJaro]

Thanks @westonruter ! That seemed to do it, no issues so far. Looking forward to the new plugin version!

[westonruter]

Added this guidance to the new wiki page: https://github.com/GoogleChromeLabs/pwa-wp/wiki/Service-Worker