The provided PHP code is intended for a WordPress child theme to add a custom canonical link to the head section of the website. The canonical link helps search engines understand the preferred URL for a page, which is crucial for SEO (Search Engine Optimization).

Breakdown of the Code:

• Enqueue Parent Styles:

function enqueue_parent_styles() {
wp_enqueue_style(‘parent-style’, get_template_directory_uri() . ‘/style.css’);
}
add_action(‘wp_enqueue_scripts’, ‘enqueue_parent_styles’);

This function (enqueue_parent_styles) is used to enqueue the parent theme’s styles. It ensures that the child theme inherits the styles from the parent theme.

• Custom Canonical Link Function:

function add_custom_canonical_link() {
$protocol = (isset($_SERVER[‘HTTPS’]) && $_SERVER[‘HTTPS’] === ‘on’) ? ‘https’ : ‘http’;
$host = $_SERVER[‘HTTP_HOST’];
$requestUri = $_SERVER[‘REQUEST_URI’];
$canonicalUrl = esc_url($protocol . ‘://’ . $host . $requestUri);

if ($canonicalUrl) {
// Check if it’s the front page or the blog page
if (is_front_page() || (is_home() && !is_paged())) {
echo ‘<link rel=”canonical” href=”‘ . $canonicalUrl . ‘” />’ . PHP_EOL;
}
}
}
add_action(‘wp_head’, ‘add_custom_canonical_link’, 999);

• This function (add_custom_canonical_link) generates the canonical URL based on the current page’s URL.
• It then checks if it’s the front page or the main blog page without pagination (!is_paged()).
• If the conditions are met, it echoes the canonical link in the head section of the website.

WordPress Child Theme:

A WordPress child theme is a theme that inherits the functionality and styling of another theme called the parent theme. Child themes are used to make modifications or customizations to a theme without directly editing the original theme’s files.

Advantages of Using a Child Theme:

1. Preserves Changes During Updates:
   • When the parent theme is updated, changes made in a child theme are preserved, preventing them from being overwritten.
2. Easy Customization:
   • Child themes allow developers to customize templates, styles, and functionality without modifying the core parent theme.
3. Organized Development:
   • It provides an organized structure for theme development, separating customizations from the core theme.

Creating a WordPress Child Theme:

To create a child theme, follow these general steps:

• Create a New Folder:
  • In the wp-content/themes/ directory, create a new folder for your child theme.

Create Stylesheet (style.css):

• Create a style.css file in the child theme folder. Include a comment block specifying the theme name, author, and template.

Create Functions File (functions.php):

• Create a functions.php file in the child theme folder. This file can be used to enqueue styles/scripts, add custom functions, or modify existing ones.

Activate the Child Theme:

• Go to the WordPress admin dashboard, navigate to “Appearance” > “Themes,” and activate your child theme.

Add Customizations:

• Customize your child theme by adding or modifying files in the child theme folder.

By following these steps, you will have a functional child theme ready for customization.

• Here is the complete code for your functions.php file

<?php
// Enqueue parent styles
function enqueue_parent_styles() {
wp_enqueue_style(‘parent-style’, get_template_directory_uri() . ‘/style.css’);
}
add_action(‘wp_enqueue_scripts’, ‘enqueue_parent_styles’);

// Add custom canonical link in the head section
function add_custom_canonical_link() {
$protocol = (isset($_SERVER[‘HTTPS’]) && $_SERVER[‘HTTPS’] === ‘on’) ? ‘https’ : ‘http’;
$host = $_SERVER[‘HTTP_HOST’];
$requestUri = $_SERVER[‘REQUEST_URI’];
$canonicalUrl = esc_url($protocol . ‘://’ . $host . $requestUri);

if ($canonicalUrl) {
// Check if it’s the front page or the blog page
if (is_front_page() || (is_home() && !is_paged())) {
echo ‘<link rel=”canonical” href=”‘ . $canonicalUrl . ‘” />’ . PHP_EOL;
}
}
}
add_action(‘wp_head’, ‘add_custom_canonical_link’, 999); // Set a high priority to ensure it runs after other actions
?>