Custom Scheduled Events. A snippet to gather any custom WP cronjobs

sceduled-events.php

<?php
/**
 * Plugin Name: Custom Scheduled Events
 * Plugin URI: https://premium.wpmudev.org/
 * Description: A snippet to gather any custom WP cronjobs
 * Task: SLS-56
 * Author: Panos Lyrakis @ WPMUDEV
 * Author URI: https://premium.wpmudev.org/
 * License: GPLv2 or later
 */


if ( ! defined( 'ABSPATH' ) || ( defined( 'WP_CLI' ) && WP_CLI ) ) {
	return;
}

if ( ! class_exists( 'WPMUDEV_Custom_Scheduled_Events' ) ) {

	class WPMUDEV_Custom_Scheduled_Events {

		private static $_instance = null;
		private $cron_tasks       = null;
		private $intervals        = array();


		/**
		 * Set up variables.
		 * In this section you can modify the variables according to your needs
		 *
		 * In `set_intervals()` you can set the "intervals" you need to have available
		 *
		 * In `set_cron_tasks` you can set the tasks that you need to be executed on each cron run
		 */

		public function set_intervals() {

			/**
			 * The custom intervals. We set here the intervals that will be available to use in our cron events.
			 *
			 * @var array $intervals
			 *
			 * Array format:
			 *  Event key (interval key) :
			 *      > `interval` : time in seconds
			 *      > `display` : a human readable name to recognize the interval
			 */

			$intervals = array(
				'every_five_minutes' => array(
					'interval' => MINUTE_IN_SECONDS * 5,
					'display'  => __( 'Every Five Minutes' ),
				),
				'every_ten_minutes'  => array(
					'interval' => MINUTE_IN_SECONDS * 10,
					'display'  => __( 'Every Ten Minutes' ),
				),
			);

			$this->intervals = $intervals;

		}


		public function set_cron_tasks() {

			/**
			 * The cron events.
			 *
			 * @var array $events
			 *
			 * Array format:
			 *  Event key (action) :
			 *      > `recurrence` : how often
			 *      > `callback` : the callback function/method
			 *      > `site_id` : when on multisite, you can define the site id this cron will be set
			 */

			$events = array(
				'custom_event'     => array(
					'recurrence' => 'every_five_minutes',
					'callback'   => array( $this, 'callback_one' ),
					'site_id'    => 1,
				),
				'custom_event_two' => array(
					'recurrence' => 'every_ten_minutes',
					'callback'   => array( $this, 'callback_two' ),
				),

			);

			$this->cron_tasks = (object) $events;

		}

		/**
		 * Callbacks.
		 * In the following section you can list your callback methods
		 */

		public function callback_one() {

			/**
			 * Run some code here
			 */

		}

		public function callback_two() {

			/**
			 * Run some code here
			 */

		}

		/**
		 * Basic methods
		 * No need to edit those (ususally)
		 */


		public static function instance() {

			if ( is_null( self::$_instance ) ) {
				self::$_instance = new WPMUDEV_Custom_Scheduled_Events();
			}
			return self::$_instance;

		}


		private function __construct() {

			$this->set_intervals();
			$this->set_cron_action();

			add_filter( 'cron_schedules', array( $this, 'set_cron_schedules' ) );
			add_action( 'wp', array( $this, 'cron_kickstarter' ), 20 );

		}

		public function set_cron_schedules( $schedules ) {

			if ( ! empty( $this->intervals ) ) {
				foreach ( $this->intervals as $key => $interval ) {
					$schedules[ $key ] = array(
						'interval' => $interval['interval'],
						'display'  => $interval['display'],
					);
				}
			}

			return $schedules;

		}


		public function cron_kickstarter() {

			$cron_tasks = $this->get_cron_tasks();

			foreach ( $cron_tasks as $cron_action => $_cron_task ) {

				$cron_task = (object) $_cron_task;

				if ( is_multisite() && property_exists( $cron_task, 'site_id' ) ) {
					if ( get_current_blog_id() !== $cron_task->site_id ) {
						continue;
					}
				}

				if ( ! wp_next_scheduled( $cron_action ) ) {
					wp_schedule_event( time(), $cron_task->recurrence, $cron_action );
				}
			}

		}


		private function set_cron_action() {

			$cron_tasks = $this->get_cron_tasks();

			foreach ( $cron_tasks as $cron_action => $_cron_task ) {

				$cron_task = (object) $_cron_task;
				add_action( $cron_action, $cron_task->callback );
			}

		}

		public function get_cron_tasks() {

			if ( empty( $this->cron_tasks ) ) {
				$this->set_cron_tasks();
			}

			return $this->cron_tasks;

		}

	}

	if ( ! function_exists( 'wpmudev_custom_scheduled_events' ) ) {

		function wpmudev_custom_scheduled_events() {
			return WPMUDEV_Custom_Scheduled_Events::instance();
		};

		add_action( 'plugins_loaded', 'wpmudev_custom_scheduled_events', 10 );
	}
}