An incredibly simple queue system for WordPress.

Installation

Drop wp-queue.php anywhere you like (preferably mu-plugins or plugins folder).

Activate if necessary.

Topics

The queue uses topics to organize things. You place data in a topic and subscribe to a topic.

Putting things on the queue

Call WP_Queue::enqueue( $topic, $data, $delay ) where $topic is the topic to place $data on the queue and $delay is the number of seconds to delay putting it on the queue.

Subscribing to topics

Call WP_Queue::subscribe( $topic, $callable ) where $topic is the topic to subscribe to and $callable is a callable to callback with. It must accept 1 argument and that argument will be the $data you pass in from WP_Queue::enqueue.

Queue Guarantees

The queue operates on a best-effort, at least once basis. It's possible to receive duplicates, however, extremely unlikely. It's also possible that a message will get lost, however, also extremely unlikely. It's built on wp-cron, so it must be enabled to receive subscriptions.

Caveats

• Requires wp-cron
• Subscriptions are called from php's shutdown hook. Use absolute paths in your callbacks if you need file access.