cms/components/com_ajax/ajax.php

<?php
/**
 * @package     Joomla.Site
 * @subpackage  com_ajax
 *
 * @copyright   Copyright (C) 2005 - 2019 Open Source Matters, Inc. All rights reserved.
 * @license     GNU General Public License version 2 or later; see LICENSE.txt
 */

defined('_JEXEC') or die;

use Joomla\CMS\Factory;
use Joomla\CMS\Language\Text;
use Joomla\CMS\Log\Log;
use Joomla\CMS\Plugin\PluginHelper;
use Joomla\CMS\Response\JsonResponse;
use Joomla\CMS\Table\Table;

/*
 * References
 *  Support plugins in your component
 * - https://docs.joomla.org/Special:MyLanguage/Supporting_plugins_in_your_component
 *
 * Best way for JSON output
 * - https://groups.google.com/d/msg/joomla-dev-cms/WsC0nA9Fixo/Ur-gPqpqh-EJ
 */

/** @var \Joomla\CMS\Application\CMSApplication $app */
$app = Factory::getApplication();
$app->allowCache(false);

// JInput object
$input = $app->input;

// Requested format passed via URL
$format = strtolower($input->getWord('format'));

// Initialize default response and module name
$results = null;
$parts   = null;

// Check for valid format
if (!$format)
{
	$results = new InvalidArgumentException(Text::_('COM_AJAX_SPECIFY_FORMAT'), 404);
}
/*
 * Module support.
 *
 * modFooHelper::getAjax() is called where 'foo' is the value
 * of the 'module' variable passed via the URL
 * (i.e. index.php?option=com_ajax&module=foo).
 *
 */
elseif ($input->get('module'))
{
	$module   = $input->get('module');
	$table    = Table::getInstance('extension');
	$moduleId = $table->find(array('type' => 'module', 'element' => 'mod_' . $module));

	if ($moduleId && $table->load($moduleId) && $table->enabled)
	{
		$helperFile = JPATH_BASE . '/modules/mod_' . $module . '/helper.php';

		if (strpos($module, '_'))
		{
			$parts = explode('_', $module);
		}
		elseif (strpos($module, '-'))
		{
			$parts = explode('-', $module);
		}

		if ($parts)
		{
			$class = 'Mod';

			foreach ($parts as $part)
			{
				$class .= ucfirst($part);
			}

			$class .= 'Helper';
		}
		else
		{
			$class = 'Mod' . ucfirst($module) . 'Helper';
		}

		$method = $input->get('method') ?: 'get';

		if (is_file($helperFile))
		{
			JLoader::register($class, $helperFile);

			if (method_exists($class, $method . 'Ajax'))
			{
				// Load language file for module
				$basePath = JPATH_BASE;
				$lang     = Factory::getLanguage();
				$lang->load('mod_' . $module, $basePath)
				||  $lang->load('mod_' . $module, $basePath . '/modules/mod_' . $module);

				try
				{
					$results = call_user_func($class . '::' . $method . 'Ajax');
				}
				catch (Exception $e)
				{
					$results = $e;
				}
			}
			// Method does not exist
			else
			{
				$results = new LogicException(Text::sprintf('COM_AJAX_METHOD_NOT_EXISTS', $method . 'Ajax'), 404);
			}
		}
		// The helper file does not exist
		else
		{
			$results = new RuntimeException(Text::sprintf('COM_AJAX_FILE_NOT_EXISTS', 'mod_' . $module . '/helper.php'), 404);
		}
	}
	// Module is not published, you do not have access to it, or it is not assigned to the current menu item
	else
	{
		$results = new LogicException(Text::sprintf('COM_AJAX_MODULE_NOT_ACCESSIBLE', 'mod_' . $module), 404);
	}
}
/*
 * Plugin support by default is based on the "Ajax" plugin group.
 * An optional 'group' variable can be passed via the URL.
 *
 * The plugin event triggered is onAjaxFoo, where 'foo' is
 * the value of the 'plugin' variable passed via the URL
 * (i.e. index.php?option=com_ajax&plugin=foo)
 *
 */
elseif ($input->get('plugin'))
{
	$group      = $input->get('group', 'ajax');
	PluginHelper::importPlugin($group);
	$plugin     = ucfirst($input->get('plugin'));

	try
	{
		$results = Factory::getApplication()->triggerEvent('onAjax' . $plugin);
	}
	catch (Exception $e)
	{
		$results = $e;
	}
}
/*
 * Template support.
 *
 * tplFooHelper::getAjax() is called where 'foo' is the value
 * of the 'template' variable passed via the URL
 * (i.e. index.php?option=com_ajax&template=foo).
 *
 */
elseif ($input->get('template'))
{
	$template   = $input->get('template');
	$table      = Table::getInstance('extension');
	$templateId = $table->find(array('type' => 'template', 'element' => $template));

	if ($templateId && $table->load($templateId) && $table->enabled)
	{
		$basePath   = ($table->client_id) ? JPATH_ADMINISTRATOR : JPATH_SITE;
		$helperFile = $basePath . '/templates/' . $template . '/helper.php';

		if (strpos($template, '_'))
		{
			$parts = explode('_', $template);
		}
		elseif (strpos($template, '-'))
		{
			$parts = explode('-', $template);
		}

		if ($parts)
		{
			$class = 'Tpl';

			foreach ($parts as $part)
			{
				$class .= ucfirst($part);
			}

			$class .= 'Helper';
		}
		else
		{
			$class = 'Tpl' . ucfirst($template) . 'Helper';
		}

		$method = $input->get('method') ?: 'get';

		if (is_file($helperFile))
		{
			JLoader::register($class, $helperFile);

			if (method_exists($class, $method . 'Ajax'))
			{
				// Load language file for template
				$lang = Factory::getLanguage();
				$lang->load('tpl_' . $template, $basePath)
				||  $lang->load('tpl_' . $template, $basePath . '/templates/' . $template);

				try
				{
					$results = call_user_func($class . '::' . $method . 'Ajax');
				}
				catch (Exception $e)
				{
					$results = $e;
				}
			}
			// Method does not exist
			else
			{
				$results = new LogicException(Text::sprintf('COM_AJAX_METHOD_NOT_EXISTS', $method . 'Ajax'), 404);
			}
		}
		// The helper file does not exist
		else
		{
			$results = new RuntimeException(Text::sprintf('COM_AJAX_FILE_NOT_EXISTS', 'tpl_' . $template . '/helper.php'), 404);
		}
	}
	// Template is not assigned to the current menu item
	else
	{
		$results = new LogicException(Text::sprintf('COM_AJAX_TEMPLATE_NOT_ACCESSIBLE', 'tpl_' . $template), 404);
	}
}

// Return the results in the desired format
switch ($format)
{
	// JSONinzed
	case 'json' :
		echo new JsonResponse($results, null, false, $input->get('ignoreMessages', true, 'bool'));

		break;

	// Handle as raw format
	default :
		// Output exception
		if ($results instanceof Exception)
		{
			// Log an error
			Log::add($results->getMessage(), Log::ERROR);

			// Set status header code
			$app->setHeader('status', $results->getCode(), true);

			// Echo exception type and message
			$out = get_class($results) . ': ' . $results->getMessage();
		}
		// Output string/ null
		elseif (is_scalar($results))
		{
			$out = (string) $results;
		}
		// Output array/ object
		else
		{
			$out = implode((array) $results);
		}

		echo $out;

		break;
}