Yii2: db access from widget - yii2

Question

Widgets should be designed to be self-contained and they should not access a database directly. But recently I've come across the code that uses a direct access to the database to retrieve widget settings, and also caches retrieved values.
Here's the part of the widget:
class DbCarousel extends Carousel
{
// ...
public function init()
{
$cacheKey = [
WidgetCarousel::className(),
$this->key
];
$items = Yii::$app->cache->get($cacheKey);
if ($items === false) {
$items = [];
$query = WidgetCarouselItem::find()
->joinWith('carousel')
->where([
'{{%widget_carousel_item}}.status' => 1,
'{{%widget_carousel}}.status' => WidgetCarousel::STATUS_ACTIVE,
'{{%widget_carousel}}.key' => $this->key,
])
->orderBy(['order' => SORT_ASC]);
foreach ($query->all() as $k => $item) {
/** #var $item \common\models\WidgetCarouselItem */
if ($item->path) {
$items[$k]['content'] = Html::img($item->getImageUrl());
}
if ($item->caption) {
$items[$k]['caption'] = $item->caption;
}
}
Yii::$app->cache->set($cacheKey, $items, 60*60*24*365);
}
$this->items = $items;
parent::init();
}
// ...
}
Question is: can widget under any circumstances access a database, or it's a sign that refactoring is needed?

Answer 1

Technically querying data and representing it are two different tasks, so such widget breaks single responsibility principle. However Yii has already a abstraction for retrieving data from database (ActiveRecord and/or ActiveQuery), so it is not that simple. You don't need to create separate data provider class for calling News::find()->newestFirst()->limit(5)->all() - usually it is easier and more pragmatic to call this query directly in LatestNewsWidget.
In general you have three situations with widgets:
Widget may display different sets of data in the same way (like GridView).
The same data may be displayed in different ways by different widgets, like widget for displaying menu - there is one menu stored in database, but depending on layout different widget should be used.
Both, way of displaying and data, is unique - for example you have only one menu and only one layout (so there is only one widget for displaying menu).
As far as two first cases clearly indicates that data source and widget should be separated, it is not that clear in third case. Personally I'm often using widgets which are responsible for retrieving all necessary data and dependencies, so I can use them simply by MyWidget::widget(). I never had any problems with this, but I'm trying to avoid too complicated DB queries - complicity usually should be hidden behind ActiveQuery abstraction. Also you always need to be prepared for refactoring and extracting querying data to separate component - at some point your unique widget with unique set of data may become not unique and separating widget and data provider may be the only sane way to keep your code DRY.