How to write your own action in Yii2 and reuse it in different controllers

Before developing any relatively large product using a framework, I would recommend deeply exploring its capabilities.

Today, we’ll talk about actions — but not the ones that are “hardcoded” into our controllers. Instead, we’ll look at actions that can be reused across different controllers by registering them through the controller’s actions() method:

public function actions()
{
	$actions = parent::actions();
	
	$actions['aj-avatar-upload'] = [
		'class' => 'commonactionuserAjaxAvatarUploadAction',
	];
	$actions['aj-avatar-delete'] = [
		'class' => 'commonactionuserAjaxAvatarDeleteAction',
	];
	
	return $actions;
}

You’ll encounter such "actions" early on, when looking at the configuration file where the error action is defined:

'errorHandler' => [
	'errorAction' => 'site/error',
],

Now, more details on usage. I didn’t invent the wheel here — and unfortunately, I hadn’t seen this approach earlier — but these types of actions are very convenient for creating reusable templates for standard operations (especially in admin panels):

• record listing
• creation
• editing
• deletion (including file or files)
• sorting

Below, I’ll just show examples of two actions — creation and deletion.

Action for creating a record:

use Yii;
use yiibaseAction;

class AddAction extends Action
{
	public $Model;
	public $model_config = [];
	public $view = '@backend/actions/object/view/add';
	public $view_model = 'ModelForm';
	public $flash;
	public $text = [];
	
	public function init()
	{
		parent::init();
		
		if($this -> flash === NULL)
		{
			$this -> flash = Yii::t('app','Object created');
		}
		
		if(isset($this -> text['title']) == false)
		{
			$this -> text['title'] = Yii::t('app', 'Creating Object');
		}
	}
	
	/**
	 * Add
	 * @return mixed
	 */
	public function run()
    {
		$LocalModel = $this -> Model;
		
		$ModelForm = new $LocalModel($this -> model_config);

		if($ModelForm -> load(Yii::$app -> request -> post()) && $ModelForm -> save())
		{
			return $this -> controller -> setFlash(['edit', 'id' => $ModelForm -> id], $this -> flash);
		}

		//View
		$this -> controller -> setBreadcrumbs($this -> text['title']);
		$this -> controller -> setTitle($this -> text['title']);
		return $this -> controller -> render($this -> view, [
			$this-> view_model => $ModelForm,
		]);
	}
}

Action configuration is done within the controller’s actions() method. If a custom view is needed, you can set the view property to point to your own view file. By “default view” I mean a layout that can be reused across different cases (without removing or adding custom form fields). For example — a form with only one Title field for creating list-type records, such as categories, regions, etc.

Action for deleting a record from the database:

use Yii;
use yiibaseAction;
use yiiwebNotFoundHttpException;

class DeleteAction extends Action
{
	public $Model;
	public $field_delete = NULL;
	public $flash = NULL;
	
	public function init()
	{
		parent::init();
		
		if($this -> flash === NULL)
		{
			$this -> flash = Yii::t('app','Object deleted');
		}
	}
	
	/**
	 * Delete row in DB
	 * @param int $id
	 * @return mixed
	 * @throws NotFoundHttpException
	 */
	public function run($id)
    {
		$LocalModel = $this -> Model;
		
		$Model = $LocalModel::findOne([
			'id' => (int) $id
		]);
		if($Model === NULL)
		{
			throw new NotFoundHttpException();
		}

		if(method_exists($Model, 'deleteFile'))
		{
			$field_delete_ar = (array) $this -> field_delete;
			foreach ($field_delete_ar as $field_delete)
			{
				$Model -> deleteFile($Model -> {$field_delete});
			}
		}
		$Model -> delete();
		
		return $this -> controller -> setFlash(['index'], $this -> flash);
	}
}

If the model defines a deleteFile method, then when this action is triggered, it will attempt to delete files from the specified fields.