Desarrollando un componente MVC : Añadiendo ACL (Access Control Levels)
[extoc]
Adding Access Control
With Joomla!’s Access Control we can define which user groups are allowed or denied to do which actions in your component. In this example we use actions that are defined in the core. For the component as a whole: core.admin (access to the configuration) and core.manage (access to the backend). And at various levels actions like create, delete and edit. Besides those core actions you can define your own actions, but that is often not necessary and is not shown in this example. View/Read Access is not managed via those actions but with View Access Levels; see general documentation about Joomla!’s ACL for that.
In the #__assets table the actual list is stored: which user groups are allowed or denied to do which actions on which resources (assets). This is the implementation of the Access Control List (ACL).
In this article we will show how to add and use access permissions at several levels of granularity: for your component as a whole, for the categories and for the individual items.
Minimal ACL requirements at the component level
There are 2 actions that need to be defined at the component level for a Joomla! 2.5 component to offer basic ACL support:
- Configure (core.admin): which groups are allowed to configure the component level permissions via the ‘Options’ toolbar button?
- Access Component (core.manage): which groups are allowed to access the component’s backend?
This basic ACL support is done in 4 simple steps:
- Add the 2 minimal component level actions to access.xml
- Add the permissions fieldset to config.xml
- Add the ‘Options’ toolbar button
- Restrict the access to the component’s backend
Add the 2 minimal component level actions to access.xml
Add an access.xml file to the root of the admin folder. Put the 2 basic actions for the com_helloworld component in this file.
admin/access.xml
Add the permissions fieldset to config.xml
Add the following permissions fieldset to admin/config.xml in order to be able to set our component level permissions
See the more elaborate config.xml example further downwards for the exact place where to insert this code.
Add the ‘Options’ toolbar button when user is authorised for it
Add the following code to admin/views/helloworlds/view.html.php:
// Options button.
if (JFactory::getUser()->authorise('core.admin', 'com_helloworld'))
{
JToolBarHelper::preferences('com_helloworld');
}
See further downwards for a more elaborated example of admin/views/helloworlds/view.html.php where this JToolBarHelper::preferences(‘com_helloworld’) is done in an addToolBar()-method together with the other toolbar buttons and the JUser->authorise()-check is done in the admin/helpers/helloworld.php helper file, resulting in the $canDo-property.
Restrict the access to the component’s backend to authorised usergroups
To control the access to the backend of the component add the following lines to the admin/helloworld.php entry-file:
// Access check: is this user allowed to access the backend of this component?
if (!JFactory::getUser()->authorise('core.manage', 'com_helloworld'))
{
return JError::raiseWarning(404, JText::_('JERROR_ALERTNOAUTHOR'));
}
See further downwards for the whole code of the admin/helloworld.php file.
Adding more actions, also at category level and item level
When adding more actions and more levels, the above described 4 steps are done too:
- Add the actions to access.xml; here we can add more actions and levels
- Add the permissions-fieldset to config.xml
- Add the ‘Options’ toolbar button
- Restrict the access to the component’s backend
In addition we also have to do the following steps:
- Add an asset_id to the item’s database table for item level access control
- Store the permissions in the assets table. Especially take care of setting the asset_id of the parent-asset
- Make the settings of the permissions at the item level editable
- Add some language strings
Describing the actions you want to control the access to
Each component (or part of it) has its own set of permissions that can be controlled. They are described in an access.xml file located at the root of the admin folder. In this helloworld-example the actions to which access is controlled are divided in three sections: at the component level, the category level and the item level. An ‘item’ is called a ‘message’ in our example component, hence the name of the third section.
admin/access.xml
Adding the setting of permissions in the component’s Preferences
Since we now use Access Control permissions in our component, we need to be able to set them at the component level. That is done in the Preferences of this component: the screen you see after clicking the ‘Options’ button. The config.xml-file is a form-definition for those Preferences. We could define the component level actions here too, as a child of the «rules» field-tag, but it is now preferred to also put those actions in access.xml: in that way all access rules for this component are on one spot.
admin/config.xml
Displaying only the right toolbar buttons
Which toolbar buttons to display depends on the Access Control permissions for the user. We put all permissions for this user in the $canDo property of the view; so we can eventually refer to it in layouts (in the edit-form for example).
In the admin/views/helloworlds/view.html.php, put this code
admin/views/helloworlds/view.html.php
items = $this->get('Items');
$this->pagination = $this->get('Pagination');
// What Access Permissions does this user have? What can (s)he do?
$this->canDo = HelloWorldHelper::getActions();
// Check for errors
if (count($errors = $this->get('Errors')))
{
JError::raiseError(500, implode('
', $errors));
return false;
}
// Set the toolbar
$this->addToolBar();
// Display the template
parent::display($tpl);
// Set the document
$this->setDocument();
}
/**
* Setting the toolbar
*/
protected function addToolBar()
{
JToolBarHelper::title(JText::_('COM_HELLOWORLD_MANAGER_HELLOWORLDS'), 'helloworld');
if ($this->canDo->get('core.create'))
{
JToolBarHelper::addNew('helloworld.add', 'JTOOLBAR_NEW');
}
if ($this->canDo->get('core.edit'))
{
JToolBarHelper::editList('helloworld.edit', 'JTOOLBAR_EDIT');
}
if ($this->canDo->get('core.delete'))
{
JToolBarHelper::deleteList('', 'helloworlds.delete', 'JTOOLBAR_DELETE');
}
if ($this->canDo->get('core.admin'))
{
JToolBarHelper::divider();
JToolBarHelper::preferences('com_helloworld');
}
}
/**
* Method to set up the document properties
*
* @return void
*/
protected function setDocument()
{
$document = JFactory::getDocument();
$document->setTitle(JText::_('COM_HELLOWORLD_ADMINISTRATION'));
}
}
In the admin/views/helloworld/view.html.php, put this code
admin/views/helloworld/view.html.php
form = $this->get('Form');
$this->item = $this->get('Item');
$this->script = $this->get('Script');
// What Access Permissions does this user have? What can (s)he do?
$this->canDo = HelloWorldHelper::getActions($this->item->id);
// Check for errors
if (count($errors = $this->get('Errors')))
{
JError::raiseError(500, implode('
', $errors));
return false;
}
// Set the toolbar
$this->addToolBar();
// Display the template
parent::display($tpl);
// Set the document
$this->setDocument();
}
/**
* Setting the toolbar
*/
protected function addToolBar()
{
$input = JFactory::getApplication()->input;
$input->set('hidemainmenu', true);
$user = JFactory::getUser();
$userId = $user->id;
$isNew = $this->item->id == 0;
JToolBarHelper::title($isNew ? JText::_('COM_HELLOWORLD_MANAGER_HELLOWORLD_NEW')
: JText::_('COM_HELLOWORLD_MANAGER_HELLOWORLD_EDIT'), 'helloworld');
// Build the actions for new and existing records.
if ($isNew)
{
// For new records, check the create permission.
if ($this->canDo->get('core.create'))
{
JToolBarHelper::apply('helloworld.apply', 'JTOOLBAR_APPLY');
JToolBarHelper::save('helloworld.save', 'JTOOLBAR_SAVE');
JToolBarHelper::custom('helloworld.save2new', 'save-new.png', 'save-new_f2.png',
'JTOOLBAR_SAVE_AND_NEW', false);
}
JToolBarHelper::cancel('helloworld.cancel', 'JTOOLBAR_CANCEL');
}
else
{
if ($this->canDo->get('core.edit'))
{
// We can save the new record
JToolBarHelper::apply('helloworld.apply', 'JTOOLBAR_APPLY');
JToolBarHelper::save('helloworld.save', 'JTOOLBAR_SAVE');
// We can save this record, but check the create permission to see
// if we can return to make a new one.
if ($this->canDo->get('core.create'))
{
JToolBarHelper::custom('helloworld.save2new', 'save-new.png', 'save-new_f2.png',
'JTOOLBAR_SAVE_AND_NEW', false);
}
}
if ($this->canDo->get('core.create'))
{
JToolBarHelper::custom('helloworld.save2copy', 'save-copy.png', 'save-copy_f2.png',
'JTOOLBAR_SAVE_AS_COPY', false);
}
JToolBarHelper::cancel('helloworld.cancel', 'JTOOLBAR_CLOSE');
}
}
/**
* Method to set up the document properties
*
* @return void
*/
protected function setDocument()
{
$isNew = $this->item->id == 0;
$document = JFactory::getDocument();
$document->setTitle($isNew ? JText::_('COM_HELLOWORLD_HELLOWORLD_CREATING')
: JText::_('COM_HELLOWORLD_HELLOWORLD_EDITING'));
$document->addScript(JURI::root() . $this->script);
$document->addScript(JURI::root() . "/administrator/components/com_helloworld"
. "/views/helloworld/submitbutton.js");
JText::script('COM_HELLOWORLD_HELLOWORLD_ERROR_UNACCEPTABLE');
}
}
These two files use the getActions method defined in the admin/helpers/helloworld.php file
In the helper-file, put this code:
admin/helpers/helloworld.php
addStyleDeclaration('.icon-48-helloworld ' .
'{background-image: url(../media/com_helloworld/images/tux-48x48.png);}');
if ($submenu == 'categories')
{
$document->setTitle(JText::_('COM_HELLOWORLD_ADMINISTRATION_CATEGORIES'));
}
}
/**
* Get the actions
*/
public static function getActions($messageId = 0)
{
jimport('joomla.access.access');
$user = JFactory::getUser();
$result = new JObject;
if (empty($messageId)) {
$assetName = 'com_helloworld';
}
else {
$assetName = 'com_helloworld.message.'.(int) $messageId;
}
$actions = JAccess::getActions('com_helloworld', 'component');
foreach ($actions as $action) {
$result->set($action->name, $user->authorise($action->name, $assetName));
}
return $result;
}
}
Restricting access to the component
The main idea in ACL is to restrict actions to groups of users. The first action to be restricted is access to the administrative backend of the component itself. With your favorite file editor, edit the admin/helloworld.php file and add the lines with the access check.
admin/helloworld.php
authorise('core.manage', 'com_helloworld'))
{
return JError::raiseWarning(404, JText::_('JERROR_ALERTNOAUTHOR'));
}
// require helper file
JLoader::register('HelloWorldHelper', dirname(__FILE__) . '/helpers/helloworld.php');
// import joomla controller library
jimport('joomla.application.component.controller');
// Get an instance of the controller prefixed by HelloWorld
$controller = JController::getInstance('HelloWorld');
// Perform the Request task
$input = JFactory::getApplication()->input;
$controller->execute($input->getCmd('task'));
// Redirect if set by the controller
$controller->redirect();
Add the asset_id column to the database table
In order to be able to work with JTable an asset_id column has to be added to the database #__helloworld table.
So, admin/sql/install.mysql.utf8.sql becomes:
admin/sql/install.mysql.utf8.sql
DROP TABLE IF EXISTS `#__helloworld`;
CREATE TABLE `#__helloworld` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`asset_id` INT(10) NOT NULL DEFAULT '0',
`greeting` varchar(25) NOT NULL,
`catid` int(11) NOT NULL DEFAULT '0',
`params` TEXT NOT NULL DEFAULT '',
PRIMARY KEY (`id`)
);
INSERT INTO `#__helloworld` (`greeting`) VALUES
('Hello World!'),
('Good bye World!');
For updates we add a sql-update-file:
admin/sql/updates/mysql/0.0.14.sql
ALTER TABLE`#__helloworld` ADD COLUMN `asset_id` INT(10) UNSIGNED NOT NULL DEFAULT '0' AFTER `id`;
Restricting access to the messages
So far we have restricted access to the component itself, but we also need to do that at message level.
To check the «core.delete» permission you need to modify the model class: admin/models/helloworld.php by adding these lines:
/**
* Method to check if it's OK to delete a message. Overwrites JModelAdmin::canDelete
*/
protected function canDelete($record)
{
if( !empty( $record->id ) ){
$user = JFactory::getUser();
return $user->authorise( "core.delete", "com_helloworld.message." . $record->id );
}
}
To check «core.edit» (and core.add if you wish) you need to update the sub-controller (not the model). I am not sure why this is so, but that’s how other standard Joomla components do it. You need to add the following lines in the file: /admin/controllers/helloworld.php
/**
* Implement to allowAdd or not
*
* Not used at this time (but you can look at how other components use it....)
* Overwrites: JControllerForm::allowAdd
*
* @param array $data
* @return bool
*/
protected function allowAdd($data = array())
{
return parent::allowAdd($data);
}
/**
* Implement to allow edit or not
* Overwrites: JControllerForm::allowEdit
*
* @param array $data
* @param string $key
* @return bool
*/
protected function allowEdit($data = array(), $key = 'id')
{
$id = isset( $data[ $key ] ) ? $data[ $key ] : 0;
if( !empty( $id ) ){
$user = JFactory::getUser();
return $user->authorise( "core.edit", "com_helloworld.message." . $id );
}
}
Please note that allowAdd simply calls its parent. I’ve put it here in case you want to actually use it in your component. If you look at your admin/access.xml file, you will notice there is no core.add action defined for «messages», so you will need to add it there as well if you want to be able to configure it in the interface.
Setting the permission values in the assets table
In order to store permissions for each message in the assets database table, we have to instruct the table class associated with the model to save those permissions in the assets table.
JTable not only provides an interface for storing the data of the record itself in the item’s database table, but also for storing the permissions for that record in the assets database table. Therefore we must add information to the bind()-method about the permission-values. We also have to provide the asset name, asset title and the id of the asset parent via the helloworld JTable. Therefore we override 3 methods:
- _getAssetName(): a unique name for this asset, by which it can be retrieved
- _getAssetTitle(): a more human-friendly way to identify the asset (not necessary unique)
- _getAssetParentId(): the asset_id of the parent in the asset database table (from whom permissions are inherited)
admin/tables/helloworld.php
loadArray($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);
}
/**
* Overridden 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;
$params->loadJSON($this->params);
$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()
{
// 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;
}
}
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.
Showing the setting of permissions on the item level
Adding the rules field to the form-definition of the edit-form
admin/models/forms/helloworld.xml
And display the ACL interface at the bottom of your Helloworld editform
admin/views/helloworld/tmpl/edit.php
form->getFieldsets('params');
?>
Adding language strings
We used 3 language strings that have to be added to the backend language-file.
admin/language/en-GB/en-GB.com_helloworld.ini
COM_HELLOWORLD_FIELDSET_RULES="Message Permissions"
COM_HELLOWORLD_ACCESS_DELETE_DESC="Is this group allowed to edit this message?"
COM_HELLOWORLD_ACCESS_DELETE_DESC="Is this group allowed to delete this message?"
Further reading
More information on actions, assets and ACL can be found on the following pages:
- General information and use: Access Control List/1.6-2.5/Tutorial
- Technical information, under construction: ACL Technique in Joomla!
- How to implement actions in your code
- Adding ACL rules to your component
Deprecated classes
For the moment we leave the deprecated JError-references as they are. They will probably still be available in Joomla! 3.x. We cannot just change them to JLog::add() statements because in Joomla! 2.5 the messages will then not be enqueued (as there is no messagequeue-logger added as is in /libraries/cms.php in Joomla! 3.0). Other solutions, like using $app->enqueueMessage() or directly throwing PHP-exceptions as showstopper are also possible, but then there would still be numerous references to JError throughout the application. For instance in the view, we now check for errors raised in the model with: count($errors = $this->get(‘Errors’)), which uses JError from the JOBject that was the base for JModel. To get the same functionality without using JError at all, we would have to change the way the Model raises those errors and warnings now. If we want to make an application that would work in Joomla! 2.5 and 3.x we can continue using JError. The moment we want to use our 3.x extensions also in 4.x we will have to change this (and probably a lot more too). This tutorial is now primarily focussed on Joomla! 2.5. So: we notice the upcoming change, but leave it there for the moment.
Since Joomla! 2.5.5 the MVC-base-classes JController, JModel and JView got proxies JControllerLegacy, JModelLegacy and JViewLegacy. You are recommended to use those proxies instead of the original classes to be forward compatibility with Joomla! CMS 3.x legacy classes.
Packaging the component
Content of your code directory
helloworld.xml
site/index.html
site/helloworld.php
site/controller.php
site/views/index.html
site/views/helloworld/index.html
site/views/helloworld/view.html.php
site/views/helloworld/tmpl/index.html
site/views/helloworld/tmpl/default.xml
site/views/helloworld/tmpl/default.php
site/models/index.html
site/models/helloworld.php
site/language/index.html
site/language/en-GB/index.html
site/language/en-GB/en-GB.com_helloworld.ini
admin/index.html
admin/access.xml
admin/config.xml
admin/helloworld.php
admin/controller.php
admin/sql/index.html
admin/sql/install.mysql.utf8.sql
admin/sql/uninstall.mysql.utf8.sql
admin/sql/updates/index.html
admin/sql/updates/mysql/index.html
admin/sql/updates/mysql/0.0.1.sql
admin/sql/updates/mysql/0.0.6.sql
admin/sql/updates/mysql/0.0.12.sql
admin/sql/updates/mysql/0.0.13.sql
admin/models/index.html
admin/models/fields/index.html
admin/models/fields/helloworld.php
admin/models/forms/index.html
admin/models/forms/helloworld.xml
admin/models/forms/helloworld.js
admin/models/rules/index.html
admin/models/rules/greeting.php
admin/models/helloworld.php
admin/models/helloworlds.php
admin/views/index.html
admin/views/helloworlds/index.html
admin/views/helloworlds/view.html.php
admin/views/helloworlds/tmpl/index.html
admin/views/helloworlds/tmpl/default.php
admin/views/helloworlds/tmpl/default_head.php
admin/views/helloworlds/tmpl/default_body.php
admin/views/helloworlds/tmpl/default_foot.php
admin/views/helloworld/index.html
admin/views/helloworld/view.html.php
admin/views/helloworld/submitbutton.js
admin/views/helloworld/tmpl/index.html
admin/views/helloworld/tmpl/edit.php
admin/helpers/index.html
admin/helpers/helloworld.php
admin/tables/index.html
admin/tables/helloworld.php
admin/language/en-GB/en-GB.com_helloworld.ini
admin/language/en-GB/en-GB.com_helloworld.sys.ini
admin/controllers/index.html
admin/controllers/helloworld.php
admin/controllers/helloworlds.php
language/en-GB/en-GB.ini
media/index.html
media/images/index.html
media/images/tux-16×16.png
media/images/tux-48×48.png
Create a compressed file of this directory or directly download the archive (TODO: zip has to be updated! Will be done coming days…) and install it using the extension manager of Joomla. You can add a menu item of this component using the menu manager in the backend.
helloworld.xml
COM_HELLOWORLD
November 2009
John Doe
john.doe@example.org
http://www.example.org
Copyright Info
License Info
0.0.14
COM_HELLOWORLD_DESCRIPTION
sql/install.mysql.utf8.sql
sql/uninstall.mysql.utf8.sql
sql/updates/mysql
index.html
helloworld.php
controller.php
views
models
language
index.html
images
index.html
config.xml
access.xml
helloworld.php
controller.php
sql
tables
models
views
controllers
helpers
language/en-GB/en-GB.com_helloworld.ini
language/en-GB/en-GB.com_helloworld.sys.ini