EVENT

bootstrap

<?php
Yii::setAlias('@common', dirname(__DIR__));
Yii::setAlias('@frontend', dirname(dirname(__DIR__)) . '/frontend');
Yii::setAlias('@backend', dirname(dirname(__DIR__)) . '/backend');
Yii::setAlias('@console', dirname(dirname(__DIR__)) . '/console');

//dependency injection container
Yii::$container->set(\common\service\SerializerInterface::class, \common\service\JsonSerializer::class);
Yii::$container->set('requestCrawler', [
    'class' => \common\service\RequestCrawlerService::class,
    'pathToSave' => dirname(__DIR__) . '/file',
    'on infoAfterSave' => function($event)
    {
        $test = new \common\service\Test();
        $test->info($event);
    }
]);

RequestCrawlerService

<?php

namespace common\service;

use Yii;
use yii\base\Component;

class RequestCrawlerService extends Component
{
    const EVENT_INFO_AFTER_SAVE = 'infoAfterSave';
    /** @var object $serializer */
    public $serializer;
    /** @var  string $pathToSave */
    public $pathToSave;

    /**
     * RequestCrawlerService constructor.
     * @param SerializerInterface $serializer
     * @param array $config
     */
    public function __construct(SerializerInterface $serializer, array $config = [])
    {
        $this->serializer = $serializer;

        parent::__construct($config);
    }

    /**
     * @param $encoded
     * @return bool
     */
    public function encodedAndSaveFile($encoded)
    {
        try {
            file_put_contents($this->pathToSave . '/' . time() . '.txt', $encoded, FILE_APPEND | LOCK_EX);
            $this->trigger(self::EVENT_INFO_AFTER_SAVE);
        } catch (\Exception $e) {
            Yii::error('ERROR Not save!  The problem with the encodedAndSaveFile ' . $e->getMessage(), 'info');
        }
        return true;
    }
}

Test

<?php

namespace common\service;

use Yii;
use yii\base\Event;

class Test
{
    /**
     * @param Event $event
     */
     public function info (Event $event)
    {
        Yii::info('Successfully saved file! use serializer: ' . get_class($event->sender->serializer), 'info');
    }
}