How to make a seo module for Yii2?

Question

Yii

Greetings!
Now I have a small site where different controllers are responsible for different url zones.
The problem is this: before that, I wrote an information book, where all subcategories and categories were implemented in one place - one controller, one method - it was not difficult to implement the ability to change the title and description at the page base level.
Here the situation is more complicated - there are 6 controllers, 3 sections are unique, each controller has 7-15 actions. Accordingly, you will have to insert the same checks everywhere and duplicate the code - well, what the hell. I don’t know all the possibilities of Yii2, the option of moving this to the main layout is spinning in my head, because he is alone on the entire front, but I consider this option only as an extremely spare one.
Tell me where to go and how to implement this.

Answer 1

Of course, you need to look at the structure, but:
You can write a helper and pull its method so as not to duplicate the code.
It is possible to write behavior and to connect in the controler.
You can write a component and attach it in the config. In the same place, hook on an event, for example, beforeAction and execute its method.

Answer 2

... to the main layout, because he is alone on the entire front, but I consider this option only as an extremely spare one.

Why? Is it a problem to connect a component at a single desired point?
I am adding:

/**
 * Зарегистрировать все тэги метаданных для страницы с правила
 */
public function applySeoRule ()
{
    # Не применяем правила если отключен
    if ( ! $this->isEnabled() ) {
        return;
    }
    # Только если есть правило для SEO
    if ( $this->hasSeoRule() ) {
        $view = Yii::$app->controller ?
            Yii::$app->controller->getView() :
            Yii::$app->getView();
        $seoRule = $this->getSeoRule();
        # Параметры индексации
        if ( $seoRule->is_no_index ) {
            $view->registerMetaTag( [
                'name' => 'robots',
                'content' => 'noindex',
            ], 'robots' );
        }
        # Основные метаданные
        if ( $seoRule->title !== '' ) {
            $view->title = $seoRule->title;
        }
        if ( $seoRule->description !== '' ) {
            $view->registerMetaTag( [
                'name' => 'description',
                'content' => $seoRule->description,
            ], 'description' );
        }
        if ( $seoRule->keywords !== '' ) {
            $view->registerMetaTag( [
                'name' => 'keywords',
                'content' => $seoRule->keywords,
            ], 'keywords' );
        }
        # Метаданные OpenGraph
        $opengraphTags = [
            'opengraph_title' => 'og:title',
            'opengraph_site_name' => 'og:site_name',
            'opengraph_url' => 'og:url',
            'opengraph_description' => 'og:description',
        ];
        $registerOpengraph = false;
        foreach ( $opengraphTags as $attribute => $tagName ) {
            if ( isset( $seoRule->$attribute ) && $seoRule->$attribute !== '' ) {
                $view->registerMetaTag( [
                    'name' => $tagName,
                    'content' => $seoRule->$attribute,
                ], $tagName );
                $registerOpengraph = true;
            }
        }
        if ( $seoRule->opengraphImage ) {
            $view->registerMetaTag( [
                'name' => 'og:image',
                'content' => $seoRule->opengraphImage->getFileUrlWithDomain(),
            ], 'og:image' );
            $registerOpengraph = true;
        }
        if ( $registerOpengraph ) {
            $view->registerMetaTag( [
                'name' => 'og:locale',
                'content' => str_replace( '-', '_', Yii::$app->language ),
            ], 'og:locale' );
            $view->registerMetaTag( [
                'name' => 'og:type',
                'content' => 'website',
            ], 'og:type' );
        }
        # Twitter OpenGraph
        $twitterTags = [
            'twitter_url' => 'twitter:url',
            'twitter_title' => 'twitter:title',
            'twitter_description' => 'twitter:description',
            'twitter_site' => 'twitter:site',
            'twitter_creator' => 'twitter:creator',
        ];
        $registerTwitter = false;
        foreach ( $twitterTags as $attribute => $tagName ) {
            if ( isset( $seoRule->$attribute ) && $seoRule->$attribute !== '' ) {
                $view->registerMetaTag( [
                    'name' => $tagName,
                    'content' => $seoRule->$attribute,
                ], $tagName );
                $registerTwitter = true;
            }
        }
        if ( $seoRule->twitterImage ) {
            $view->registerMetaTag( [
                'name' => 'twitter:image',
                'content' => $seoRule->twitterImage->getFileUrlWithDomain(),
            ], 'twitter:image' );
            $registerTwitter = true;
        }
        if ( $registerTwitter ) {
            $view->registerMetaTag( [
                'name' => 'twitter:card',
                'content' => 'summary',
            ], 'twitter:card' );
        }
    }
}