Dynamically add year variable to meta title / description in Magento 2

Question

I am trying to automatically add the current year to the meta title and description in for example category-pages. I want to achieve something like this:

Meta title: "The best category items for {{year}}" >> "The best category items for 2019"

What would be the easiest way to do this?

Answer 1

In this case, you can use event/observer.

Fire an observer on the event catalog_category_load_after at frontend area set meta description on the fly.

Create events.xml at app/code/StackExchange/Magento/etc/frontend/ and as `events.xml location under on frontend and this event only fire for frontend area.

events.xml code

<?xml version="1.0" ?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Event/etc/events.xsd">
    <event name="catalog_category_load_after">
        <observer instance="StackExchange\Magento\Observer\Frontend\Catalog\CategoryLoadAfter" 
                  name="stackexchange_magento_observer_frontend_catalog_categoryloadafter_catalog_product_load_after"
        />
    </event>
</config>

Create Observer class CategoryLoadAfter at app/code/StackExchange/Magento/Observer/Frontend/Catalog/.

CategoryLoadAfter.php code

<?php
namespace StackExchange\Magento\Observer\Frontend\Catalog;

class CategoryLoadAfter implements \Magento\Framework\Event\ObserverInterface {

    /**
     * @var \Psr\Log\LoggerInterface
     */
    private $logger;

    public function __construct(
     \Psr\Log\LoggerInterface $logger
    ) {

        $this->logger = $logger;
    }
    /**
     * Execute observer
     *
     * @param \Magento\Framework\Event\Observer $observer
     * @return void
     */
    public function execute(
        \Magento\Framework\Event\Observer $observer
    ) {
        $this->logger->debug(__METHOD__);
        $category = $observer->getEvent()->getCategory();
        if ($category instanceof \Magento\Catalog\Model\Category) {
            $oldMetaTitle = $category->getMetaTitle();
            $oldMetaDescription = $category->getMetaDescription();
            $oldMetaKeyword = $category->getMetaKeywords();
            $category->setMetaTitle(str_replace("{{year}}",date('Y'),$oldMetaTitle));
            $category->setMetaDescription(str_replace("{{year}}",date('Y'),$oldMetaDescription));
            $category->setMetaKeywords(str_replace("{{year}}",date('Y'),$oldMetaKeyword));
        }
    }

}

Also, your module must have:

1. app/code/{Vendor}/{Modulename}/etc/module.xml
2. app/code/{Vendor}/{Modulename}/composer.json
3. app/code/{Vendor}/{Modulename}/registration.php

After adding the event you should flush the cache.