View source for Developing a MVC Component/Adding ACL/fr

=== Setting the permission values in the assets table ===

In order to store permissions for each message in the assets database table, we have to instruct the table class associated with the model to save those permissions in the assets table.

JTable not only provides an interface for storing the data of the record itself in the item's database table, but also for storing the permissions for that record in the assets database table. Therefore we must add information to the bind()-method about the permission-values. We also  have to provide the asset name, asset title and the id of the asset parent via the helloworld JTable. Therefore we override 3 methods:
* _getAssetName(): a unique name for this asset, by which it can be retrieved
* _getAssetTitle(): a more human-friendly way to identify the asset (not necessary unique)
* _getAssetParentId(): the asset_id of the parent in the asset database table (from whom permissions are inherited)

<span id="admin/tables/helloworld.php">
<tt>admin/tables/helloworld.php</tt>
<source lang="php" highlight="45-52,80-133">
<?php
/**
 * @package     Joomla.Administrator
 * @subpackage  com_helloworld
 *
 * @copyright   Copyright (C) 2005 - 2015 Open Source Matters, Inc. All rights reserved.
 * @license     GNU General Public License version 2 or later; see LICENSE.txt
 */
// No direct access
defined('_JEXEC') or die('Restricted access');

/**
 * Hello Table class
 *
 * @since  0.0.1
 */
class HelloWorldTableHelloWorld extends JTable
{
	/**
	 * Constructor
	 *
	 * @param   JDatabaseDriver  &$db  A database connector object
	 */
	function __construct(&$db)
	{
		parent::__construct('#__helloworld', 'id', $db);
	}
	/**
	 * Overloaded bind function
	 *
	 * @param       array           named array
	 * @return      null|string     null is operation was satisfactory, otherwise returns an error
	 * @see JTable:bind
	 * @since 1.5
	 */
	public function bind($array, $ignore = '')
	{
		if (isset($array['params']) && is_array($array['params']))
		{
			// Convert the params field to a string.
			$parameter = new JRegistry;
			$parameter->loadArray($array['params']);
			$array['params'] = (string)$parameter;
		}

		// Bind the rules.
		if (isset($array['rules']) && is_array($array['rules']))
		{
			$rules = new JAccessRules($array['rules']);
			$this->setRules($rules);
		}

		return parent::bind($array, $ignore);
	}

	/**
	 * Overloaded load function
	 *
	 * @param       int $pk primary key
	 * @param       boolean $reset reset data
	 * @return      boolean
	 * @see JTable:load
	 */
	public function load($pk = null, $reset = true)
	{
		if (parent::load($pk, $reset))
		{
			// Convert the params field to a registry.
			$params = new JRegistry;
			$params->loadString($this->params, 'JSON');

			$this->params = $params;
			return true;
		}
		else
		{
			return false;
		}
	}
	/**
	 * Method to compute the default name of the asset.
	 * The default name is in the form `table_name.id`
	 * where id is the value of the primary key of the table.
	 *
	 * @return	string
	 * @since	2.5
	 */
	protected function _getAssetName()
	{
		$k = $this->_tbl_key;
		return 'com_helloworld.message.'.(int) $this->$k;
	}
	/**
	 * Method to return the title to use for the asset table.
	 *
	 * @return	string
	 * @since	2.5
	 */
	protected function _getAssetTitle()
	{
		return $this->greeting;
	}
	/**
	 * Method to get the asset-parent-id of the item
	 *
	 * @return	int
	 */
	protected function _getAssetParentId(JTable $table = NULL, $id = NULL)
	{
		// We will retrieve the parent-asset from the Asset-table
		$assetParent = JTable::getInstance('Asset');
		// Default: if no asset-parent can be found we take the global asset
		$assetParentId = $assetParent->getRootId();

		// Find the parent-asset
		if (($this->catid)&& !empty($this->catid))
		{
			// The item has a category as asset-parent
			$assetParent->loadByName('com_helloworld.category.' . (int) $this->catid);
		}
		else
		{
			// The item has the component as asset-parent
			$assetParent->loadByName('com_helloworld');
		}

		// Return the found asset-parent-id
		if ($assetParent->id)
		{
			$assetParentId=$assetParent->id;
		}
		return $assetParentId;
	}
}

</source>
</span>

This code for _getAssetParentId() above uses JTableAsset to retrieve the asset_id of the asset-parent. This is different from the code in the current version of com_content, where the asset_id of the category is retrieved from the #__categories database table. That is another possibility; many ways leading to Rome. In com_content however, if an item would not be under a category, then the asset_id of the global asset is returned. That would of course not be right, but is fixed there by providing a default category "uncategorised", so that an article is ''always'' under a category. That is why you cannot just copy the code of _getAssetParentId() in com_content to your own component. The code above is more general.