WordPress - Delete expired transients

model-transients.php

<?php
/**
 * Do not allow direct access
 *
 * @since 1.0
 */
if ( ! defined( 'ABSPATH' ) ) die( 'Nothing to find Ma\'am..' );

/**
 * Your Plugin Name - Model Transients
 *
 * @since 1.0
 */
if ( ! class_exists( 'modelTransients' ) )
{

    final class modelTransients
    {

	/**
	 * Set properties
	 *
	 * @since 1.0
	 */
	private $wpdb;

        /**
         * Constructor
         *
         * @since 1.0
         */
        public function __construct()
        {

	    global $wpdb;

	    $this->wpdb = $wpdb;

        } // end constructor

        /**
         * Clear expired transients
         *
         * @since 1.0
         */
        public function expiredTransients()
        {

            $query = "Select * FROM {$this->wpdb->options} WHERE option_name LIKE '%_transient_timeout_%'";

            $rows = $this->wpdb->get_results( $query );

            $time = time() - MINUTE_IN_SECONDS;

            foreach ( $rows as $row ) :

                if ( (int) $row->option_value < $time )
                    $arr[] = $row->option_name;

            endforeach;

            if ( isset( $arr ) )
                foreach ( $arr as $key => $transient )
                    delete_transient( str_replace( '_transient_timeout_', '', $transient ) );

        } // end expiredTransients
    } // end class
} // end if



/**
 * Your Plugin Name - Controller Helpers
 *
 * @since 1.0
 */
if ( ! class_exists( 'controllerHelpers' ) )
{

    final class controllerHelpers
    {

        /**
         * Get the next 12:00 am timestamp
         *
         * @since 1.0
         */
        public function twelveTimestamp()
        {

            $time = time();

            $hour = (int) date( 'H', $time );

            if ( $hour >= 11 ) // to be sure
                $add = 24 - $hour + 2; // next day

            if ( isset( $add ) )
                $setTarget = date( 'Y-m-d', $time + ( $add * HOUR_IN_SECONDS ) ) . ' 12:00:00';

            else
                $setTarget = date( 'Y-m-d', $time ) . ' 12:00:00';

            return DateTime::createFromFormat( 'Y-m-d H:i:s', $setTarget )->getTimestamp();

        } // end twelveTimestamp
    } // end class
} // end if



//It makes sense to set it to a sheduled hook

$prefix = 'my_pref';

if ( ! wp_next_scheduled( $prefix . '_scheduled_hook' ) )
  wp_schedule_event( ( new controllerHelpers )->twelveTimestamp(), 'daily', $prefix . '_scheduled_hook' );

add_action( $prefix . '_scheduled_hook', [ ( new modelTransients ), 'expiredTransients' ] );



//To clear the sheduled hook

$time = wp_next_scheduled( $prefix . '_scheduled_hook' );

wp_unschedule_event( $time, $prefix . '_scheduled_hook' );