ProcessWire Module Template. It demonstrates the Module interface and how hooks are added

ModuleName.module

<?php

/**
 * ProcessWire Module Template
 *
 * Demonstrates the Module interface and how to add hooks.
 * 
 * ProcessWire 2.x 
 * Copyright (C) 2010 by Ryan Cramer 
 * Licensed under GNU/GPL v2, see LICENSE.TXT
 * 
 * http://www.processwire.com
 * http://www.ryancramer.com
 *
 */

class ModuleName extends WireData implements Module {

	/**
	 * getModuleInfo is a module required by all modules to tell ProcessWire about them
	 *
	 * @return array
	 *
	 */
	public static function getModuleInfo() {

		return array(
			'title' => 'ModuleName', 
			'version' => 100, 
			'summary' => '',
			'href' => '',
			'singular' => true,
			'autoload' => true
			);
	}


	public function init() {

		// add a hook after each page is rendered and modify the output
		$this->addHookAfter('Page::render', $this, 'example2'); 

	}


	public function example2($event) {

		$page = $event->object; 

		// don't add this to the admin pages
		if($page->template == 'admin') return;

		// add a "Hello World" paragraph right before the closing body tag
		$event->return = str_replace("</body>", "<p>Hello World!</p></body>", $event->return); 
	}

	
}