Overriding Only a Few Specific Canonical Links with Default Value = Yes in Magento 2: A Step-by-Step Guide

Magento 2 is an incredibly powerful e-commerce platform, but sometimes its default settings can be a bit… restrictive. One such example is the canonical links feature, which, while useful, can be overly aggressive in its canonicalization of URLs. In this article, we’ll explore how to override only a few specific canonical links with a default value of “Yes” in Magento 2, giving you more control over your website’s SEO.

Understanding Canonical Links in Magento 2

Before we dive into the solution, let’s quickly cover what canonical links are and how they work in Magento 2. Canonical links are a way to specify a preferred version of a webpage to search engines, helping to prevent duplicate content issues and improve page ranking. In Magento 2, canonical links are enabled by default, and they’re usually a good thing – but sometimes, they can cause problems.

For instance, if you have a product with multiple URLs (e.g., example.com/product-1 and example.com/category/product-1), Magento 2 will automatically canonicalize the URLs to the first one, which might not be the one you want to prioritize. That’s where overriding specific canonical links comes in.

Why Override Canonical Links?

There are several reasons why you might want to override specific canonical links in Magento 2:

• Priority URLs: You might want to prioritize specific URLs over others, especially if they have better SEO performance or are more user-friendly.

• Canonicalization issues: Magento 2’s canonicalization algorithm might not always get it right, leading to incorrect canonical links that harm your website’s SEO.

• Custom requirements: You might have custom requirements for specific products or categories that don’t fit with Magento 2’s default canonicalization rules.

Preparing for the Override

Before we start overriding canonical links, make sure you have the following:

• A working Magento 2 installation (obviously!)

• A basic understanding of PHP and Magento 2’s module structure

• A code editor or IDE of your choice (we’ll use Visual Studio Code in this example)

• A Magento 2 module (we’ll create a new one for this example)

Creating a New Module in Magento 2

To override canonical links, we’ll create a new Magento 2 module. Create a new directory in the app/code directory and name it (e.g., Vendor_Name/CanonicalOverride). Inside this directory, create the following files:

app/code/Vendor_Name/CanonicalOverride
├── Composer.json
├── registration.php
├── etc
│   ├── module.xml
│   └── catalog
│       └── attributes.xml
├── Model
│   └── Resolver
│       └── CanonicalUrl.php
└── di.xml

Edit the module.xml file to add the module’s metadata:

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:App/etc/module_config.xsd">
    <module name="Vendor_Name_CanonicalOverride" setup_version="1.0.0">
        <!-- ... -->
    </module>
</config>

Overriding the Canonical URL Resolver

The next step is to override the canonical URL resolver. In the Model/Resolver directory, create a new file called CanonicalUrl.php and add the following code:

<?php

namespace Vendor_Name\CanonicalOverride\Model\Resolver;

use Magento\Catalog\Model\UrlResolver as MagentoUrlResolver;
use Magento\Framework\UrlInterface;

class CanonicalUrl extends MagentoUrlResolver
{
    public function getCanonicalUrl($product, $params = [])
    {
        // Your custom logic to determine the canonical URL goes here
        // For example, let's say we want to prioritize URLs with a specific parameter
        if (isset($params['specific_parameter'])) {
            return $this->getUrl($product, ['_query' => ['specific_parameter' => 'value']]);
        }

        // If no custom logic applies, fall back to the default behavior
        return parent::getCanonicalUrl($product, $params);
    }
}

This code overrides the default canonical URL resolver and adds a custom logic to prioritize URLs with a specific parameter. You can add your own custom logic here to fit your requirements.

Registering the Override

To register the override, edit the di.xml file:

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
    <type name="Magento\Catalog\Model\UrlResolver"  instance="Vendor_Name\CanonicalOverride\Model\Resolver\CanonicalUrl"/>
</config>

This code tells Magento 2 to use our custom canonical URL resolver instead of the default one.

Enabling the Module

Finally, enable the module by running the following command in your terminal:

php bin/magento module:enable Vendor_Name_CanonicalOverride

Flush the cache to apply the changes:

php bin/magento cache:flush

Testing the Override

Test your override by navigating to a product page that should have a customized canonical URL. Check the HTML source to verify that the canonical link has been overridden correctly.

Conclusion

Overriding canonical links in Magento 2 can be a complex task, but with this guide, you should now have a better understanding of how to create a custom canonical URL resolver and register it in Magento 2. Remember to test your override thoroughly to ensure it’s working as expected.

By following these steps, you’ll have more control over your website’s SEO and be able to prioritize specific URLs for better search engine ranking and user experience. Happy coding!

Module Files	Purpose
Composer.json	Module metadata
registration.php	Module registration
etc/module.xml	Module configuration
Model/Resolver/CanonicalUrl.php	Custom canonical URL resolver
di.xml	Dependency injection configuration

Note: This article is for educational purposes only and should not be considered as professional advice. Testing and validation of the code are the responsibility of the reader.

Frequently Asked Question

Get ready to master the art of canonical links in Magento 2!