Using external actions in YII

In Yii, you can define controller actions as separate classes and then connect them to your
controllers. This way, you can reuse some common functionality.
For example, you can move backend for autocomplete fields to an action and save some time
by not having to write it over and over again.
Another simple example that we will review is deleting a model.
Getting ready
1. Set up a new application using yiic webapp.
2. Create a DB schema with the following script:
CREATE TABLE `post` (
`id` int(10) unsigned NOT NULL auto_increment,
`created_on` int(11) unsigned NOT NULL,
`title` varchar(255) NOT NULL,
`content` text NOT NULL,
PRIMARY KEY (`id`)
);
CREATE TABLE `user` (
`id` int(10) unsigned NOT NULL auto_increment,
`username` varchar(200) NOT NULL,
`password` char(40) NOT NULL,
PRIMARY KEY (`id`)
);
3. Generate Post and User models using Gii.
How to do it...
1. Let's write a usual delete action for posts first, as follows:
class PostController extends CController
{
function actionIndex()
{
$posts = Post::model()->findAll();
$this->render('index', array(
'posts' => $posts,
));}
function actionDelete($id)
{
$post = Post::model()->findByPk($id);
if(!$post)
throw new CHttpException(404);
if($post->delete())
$this->redirect('post/index');
throw new CHttpException(500);
}
}
We have defined two actions. One lists all posts and another deletes a post specified
if it exists and redirects back to index action.
2. Now, let's do the same in a separate action class. Create DeleteAction.php in
your protected/components directory as follows:
class DeleteAction extends CAction
{
function run()
{
if(empty($_GET['id']))
throw new CHttpException(404);
$post = Post::model()->findByPk($_GET['id']);
if(!$post)
throw new CHttpException(404);
if($post->delete())
$this->redirect('post/index');
throw new CHttpException(500);
}
}
3. Let's use it inside our controller. Delete actionDelete, we will not need it anymore.
Then, add the actions method:
class PostController extends CController
{
function actions()
{
return array(
'delete' => 'DeleteAction',
);
}
…
}
4. OK. Now, we are using external delete action for post controller, but what about the
user controller? To use our DeleteAction with UserController we need to
customize it first. We do this as follows:
class DeleteAction extends CAction
{
public $pk = 'id';
public $redirectTo = 'index';
public $modelClass;
function run()
{
if(empty($_GET[$this->pk]))
throw new CHttpException(404);
$model = CActiveRecord::model($this->modelClass)
->findByPk($_GET[$this->pk]);
if(!$model)
throw new CHttpException(404);
if($model->delete())
$this->redirect($this->redirectTo);
throw new CHttpException(500);
}
}
5. Now, we can use this action for both post controller and user controller. For post
controller, we do this as follows:
class PostController extends CController
{
function actions()
{
return array(
'delete' => array('class' => 'DeleteAction',
'modelClass' => 'Post',
);
);
}
…
}
6. For user controller, we do this as follows:
class UserController extends CController
{
function actions()
{
return array(
'delete' => array(
'class' => 'DeleteAction',
'modelClass' => 'User',
);
);
}
…
}
7. This way, you can save yourself a lot of time by implementing and reusing external
actions for tasks of a similar type.
How it works...
Every controller can be built from external actions like a puzzle from pieces. The difference
is that you can make external actions very flexible and reuse them in many places. In the
final version of DeleteAction, we defined some public properties. As DeleteAction is
a component, we can set its properties through config. In our case, we pass config into the
actions controller method used to add actions to a module.