WordPress Function to Perform Plugin Update Routine

WordPress Function to Perform Plugin Update Routine.php

<?php

/**
 * Establish a routine of tasks to perform when this plugin is updated.
 *
 * @package WordPress
 * @subpackage sjf-et
 * @since SJF ET 1.5.5
 */

function sjf_et_admin_update_init() {
	new SJF_Ecwid_Admin_Update();
}
add_action( 'plugins_loaded', 'sjf_et_admin_update_init' );

class SJF_Ecwid_Admin_Update {

	function __construct() {
		add_action( 'admin_init', array( $this, 'dump_transients' ) );
	}

	/**
	 * Determine if our plugin is in need of maintenance tasks as a result of having been updated.
	 * 
	 * @return boolean Returns TRUE if our plugin has been updated since the last check, else FALSE.
	 */
	function is_old() {

		// Build a key to refer to the plugin version in the database.
		$namespace = SJF_Ecwid_Helpers::get_namespace();
		$key       = $namespace . '_version';
		
		// Grab the plugin version from the database.
		$db_v = get_option( $key );
		
		/**
		 * Compare the db version to the file version.
		 * We're assuming that we remember to update the file version when we update the plugin.
		 */
		if( SJF_ET_VERSION != $db_v ) {
			
			// Update the db version to mimic the file version.
			update_option( $key, SJF_ET_VERSION );

			wp_die(45);

			// Return TRUE -- yes, we need to run update tasks.
			return TRUE;
		
		// No, we don't need to run update tasks.
		} else {
			return FALSE;
		}

	}

	/**
	 * One of the tasks we perform upon updating is to dump our transients, which includes flushing rules.
	 */
	function dump_transients() {

		if( ! $this -> is_old() ) { return FALSE; }

		$transients = new SJF_Ecwid_Transients( FALSE );
	}

}