BlogPublishDate.module

<?php

namespace ProcessWire;

/**
 * Blog Post Publish Date Module for ProcessWire.
 *
 * This small autoload module sets a Blog Post's published date (field = 'blog_date')
 * Based on the code here: https://processwire.com/talk/topic/2448-show-date-published-on-a-page/ by SiNNuT and Soma
 *
 * @author Francis Otieno (Kongondo) <kongondo@gmail.com>
 * @author Some code from SiNNuT, Soma
 *
 * https://github.com/kongondo/Blog
 * Created August 2014
 *
 * ProcessWire 3.x
 * Copyright (C) 2016 by Ryan Cramer
 * Licensed under GNU/GPL v2, see LICENSE.TXT
 *
 * http://www.processwire.com
 *
 */

class BlogPublishDate extends WireData implements Module {

	/**
	 * Return information about this module (required).
	 *
	 *	@access public
	 *	@return array module info
	 *
	 */
	public static function getModuleInfo() {

		return array(
			'title' => 'Blog Post Publish Date',
			'summary' => 'Automatically set a Blog Post publish date on publish',
			'author' => 'Francis Otieno (Kongondo)',
			'version' => '2.4.6',
			'href' => 'https://processwire.com/talk/topic/17105-module-blog/',
			'singular' => true,
			'autoload' => true,
			'requires' => 'ProcessBlog'

		);
	}

	/**
	 *	Initialise the module.
	 *
	 * ProcessWire calls this when the module is loaded. For 'autoload' modules, this will be called.
	 * when ProcessWire's API is ready. As a result, this is a good place to attach hooks.
	 *
	 *	@access public
	 *
	 */
	public function init() {
		// add a hook after $page->save (only on Blog Posts pages)
		$this->wire('pages')->addHookAfter('save', $this, 'afterSave');
	}

	/**
	 *	Hook to set a Blog Post's 'published date' (if not set already) when a Blog Post is published.
	 *
	 *  This function will not empty any values extant in 'blog_date'.
	 *	This is to preserve the original Blog Post publish date.
	 *
	 *	@access public
	 *
	 */
	public function afterSave($event) {

		// get the page object saved
		$page = $event->argumentsByName('page');

		// only on pages that use the template 'blog-post
		if ($page->template != 'blog-post') return;

		/*	- we don't want to touch unpublished pages ['pending' and 'expired']
	    	- neither published pages with blog_date already filled in
	    	- nor if for some reason field 'blog_date' not found in the 'blog-post' template and page is published
	   	*/

		if ($page->is(Page::statusUnpublished) || $page->blog_date || !$page->template->hasField('blog_date')) return;

		// if page is published and blog_field not populated, add current timestamp
		$page->blog_date = time();
		$page->save('blog_date');
	}

	/**
	 * 	Called only when the module is installed.
	 *
	 *	@access public
	 *
	 */
	public function ___install() {

		// Don't need to add anything here...

	}

	/**
	 *	Called only when the module is uninstalled.
	 *
	 *	This should return the site to the same state it was in before the module was installed.
	 *
	 *	@access public
	 *
	 */
	public function ___uninstall() {

		// Don't need to add anything here...

	}
}