WordPress: rendere gli URL relativi

Possiamo rendere gli URL di WordPress relativi con molta semplicità.

Il seguente codice, da inserire in functions.php, fa uso delle funzioni anonime di PHP (5.3 e superiori):

add_action( 'template_redirect', 'my_relative_url' );

function my_relative_url() {
  $filters = array(
	 
	 // Post e categorie 
	  
    'bloginfo_url',
    'the_permalink',
    'wp_list_pages',
    'wp_list_categories',
    'the_content_more_link',
    'the_tags',
    'the_author_posts_link',
    'post_link',       
    'post_type_link',  
    'page_link',       
    'attachment_link', 
    'get_shortlink', 
    'post_type_archive_link',
    'get_pagenum_link',          
    'get_comments_pagenum_link',
    'term_link',   
    'search_link',
    'day_link',   
    'month_link',
    'year_link',

    // URL dell'installazione
    'option_siteurl',
    'blog_option_siteurl',
    'option_home',
    'admin_url',
    'get_admin_url',
    'get_site_url',
    'network_admin_url',
    'home_url',
    'includes_url',
    'site_url',
    'site_option_siteurl',
    'network_home_url',
    'network_site_url',

    // Debug
    'get_the_author_url',
    'get_comment_link',
    'wp_get_attachment_image_src',
    'wp_get_attachment_thumb_url',
    'wp_get_attachment_url',
    'wp_login_url',
    'wp_logout_url',
    'wp_lostpassword_url',
    'get_stylesheet_uri',
    'get_stylesheet_directory_uri',
    'plugins_url',
    'plugin_dir_url',
    'stylesheet_directory_uri',
    'get_template_directory_uri',
    'template_directory_uri',
    'get_locale_stylesheet_uri',
    'script_loader_src', 
    'style_loader_src',
    'get_theme_root_uri'
  );
  
  $home_url = home_url();
  
  $filter_fn = function( $link ) use ( $home_url ) {
    if ( !is_array( $link ) && strpos( $link, $home_url ) === 0 ) {
      return wp_make_link_relative( $link );
    } else {
      return $link;
    }
  };

  foreach ( $filters as $filter ) {
    add_filter( $filter, $filter_fn );
  }
}