simple_ajax/SimpleAjaxFrontend.php

<?php

/**
 * Contao Open Source CMS
 * Copyright (C) 2005-2011 Leo Feyer
 *
 * This program is free software: you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation, either
 * version 3 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this program. If not, please visit the Free
 * Software Foundation website at <http://www.gnu.org/licenses/>.
 *
 * PHP version 5
 * @copyright	Leo Unglaub 2012
 * @author		Leo Unglaub <leo@leo-unglaub.net>
 * @package		simple_ajax
 * @license		LGPL
 */


// simple trick for Contao < 2.10
$arrPost = $_POST;
unset($_POST);


// inizialize the contao framework
define('TL_MODE', 'FE');
require('system/initialize.php');


// write the post data back into the array
$_POST = $arrPost;


/**
 * Class SimpleAjaxFrontend
 * Contain methods to catch ajax requests and send responses back to the client.
 *
 * Description
 * ```````````
 *
 * The usage of the SimpleAjax extensions is very easy. The extension provides
 * the hook $GLOBALS['TL_HOOKS']['simpleAjax'] for extension developers. You
 * simply have to register your class/method and the extension will call
 * your class if there is an incomming ajax request.
 *
 * You simply have to deside if it's an ajax request for your module and return
 * the data you want.
 *
 * There are a few thinks you should know about the extension:
 * 	* YOU have the full controll over the response. That also means
 * 	  that you have to set the correct header.
 *  * YOU have to terminate the request after you have send the response.
 * 	* If the ajax request is not for your method you simply have nothing to
 * 	* return.
 *
 *
 * Usage
 * `````
 * // config.php
 * $GLOBALS['TL_HOOKS']['simpleAjaxFrontend'][] = array('MyClassFrontend', 'myMethod');
 *
 * // MyClassFrontend.php
 * class MyClassFrontend extends System
 * {
 * 	public function myMethod()
 * 	{
 * 		if ($this->Input->get('acid') == 'myrequest')
 * 		{
 * 			$arrReturn = array('foo', 'bar', 'foobar');
 *
 * 			header('Content-Type: application/json');
 * 			echo json_encode($arrReturn);
 * 			exit;
 * 		}
 * 	}
 * }
 */
class SimpleAjaxFrontend extends Frontend
{
	/**
	 * Set some important constants
	 *
	 * @param	void
	 * @return	void
	 */
	public function __construct()
	{
		// call the constructor from Frontend
		parent::__construct();

		// check if a user is logged in
		define('BE_USER_LOGGED_IN', $this->getLoginStatus('BE_USER_AUTH'));
		define('FE_USER_LOGGED_IN', $this->getLoginStatus('FE_USER_AUTH'));

		// set static url's in case the user generated HTML code
		$this->setStaticUrl('TL_FILES_URL', $GLOBALS['TL_CONFIG']['staticFiles']);
		$this->setStaticUrl('TL_SCRIPT_URL', $GLOBALS['TL_CONFIG']['staticSystem']);
		$this->setStaticUrl('TL_PLUGINS_URL', $GLOBALS['TL_CONFIG']['staticPlugins']);
	}


	/**
	 * Get the ajax request and call all hooks
	 *
	 * @param	void
	 * @return	void
	 */
	public function run()
	{
		// run the global hook
		if (is_array($GLOBALS['TL_HOOKS']['simpleAjax']) && count($GLOBALS['TL_HOOKS']['simpleAjax']) > 0)
		{
			// execute every registered callback
			foreach ($GLOBALS['TL_HOOKS']['simpleAjax'] as $callback)
			{
				$this->import($callback[0]);
				$this->$callback[0]->$callback[1]();
			}
		}

		// run the frontend exclusive hook
		if (is_array($GLOBALS['TL_HOOKS']['simpleAjaxFrontend']) && count($GLOBALS['TL_HOOKS']['simpleAjaxFrontend']) > 0)
		{
			// execute every registered callback
			foreach ($GLOBALS['TL_HOOKS']['simpleAjaxFrontend'] as $callback)
			{
				$this->import($callback[0]);
				$this->$callback[0]->$callback[1]();
			}
		}

		// if there is no other output, we generate a 412 error response
		header('HTTP/1.1 412 Precondition Failed');
		die('Simple Ajax: Invalid AJAX call.');
	}
}


// create a SimpleAjax instance and run it
$objSimpleAjaxFrontend = new SimpleAjaxFrontend();
$objSimpleAjaxFrontend->run();

?>