Solution to Code Challenge 5 from "Refactoring Tweaks Workbook"

code-challenge-5.php

/* Code Challenge 5, from “Refactoring Tweaks Workbook” by Tonya Mork ( 2016, LeanPub (https://leanpub.com/littlegreenbookofrefactoringtweaks-workbook) ). */  

/***************************************************
 *
 * Original code to be refactored.
 *
 **************************************************/
 
class Session {
	
	/**
	 * Flag whether or not the internal collection has been changed.
	 *
	 * @var bool
	 */
	protected $dirty = false;
	..
	/**
	 * Write the data from the current session to the data storage system.
	 */
	public function write_data() {
		$option_key = "_prefix_session_{$this->session_id}";

		// Only write the collection to the DB if it's changed.
		if ( $this->dirty ) {
			if ( false === get_option( $option_key ) ) {
				add_option( "_prefix_session_{$this->session_id}", $this->container, '', 'no' );
				add_option( "_prefix_session_expires_{$this->session_id}", $this->expires, '', 'no' );
			} else {
				delete_option( "_prefix_session_{$this->session_id}" );
				add_option( "_prefix_session_{$this->session_id}", $this->container, '', 'no' );
			}
		}
	}
	..
}

/***************************************************
 *
 * Refactored Code
 *
 **************************************************/
 
 class Session {

	/**
	 * Flag whether or not the internal collection has been changed.
	 *
	 * @var bool
	 */
	protected $dirty = false;
    
	/**
	 * Write the data from the current session to the data storage system.
	 */
	public function write_data() {
		if ( ! $this->is_dirty() ) {
			return;
		}
		
		$this->write_collection_to_db();
	}

	protected function is_dirty( $dirty ) {
		return $dirty = true;
	}

	protected function write_collection_to_db() {
		$option_key = "_prefix_session_{$this->session_id}";

		if ( false === get_option( $option_key ) ) {
			add_option( "_prefix_session_{$this->session_id}", $this->container, '', 'no' );
			add_option( "_prefix_session_expires_{$this->session_id}", $this->expires, '', 'no' );
		} else {
			delete_option( "_prefix_session_{$this->session_id}" );
			add_option( "_prefix_session_{$this->session_id}", $this->container, '', 'no' );
		}
	}
}