My WordPress ‘cleanup’ script

13th May, 2015

I include the following, or something similar, in most of my WordPress projects. It standardises some awkward behaviours, removes some superfluous settings and capabilities, and enhances/improves some default functions and approaches.

Warning – do not simply copy and paste this into your theme/functions; it’ll need adapting to fit your use-case, and will likely cause as many problems as it solves if not tweaked and refined to fit your needs.

/**
 * Removes WP cruft
 */
class Cruft {

	/**
	 * Register the integration.
	 *
	 * @return void
	 */
	public static function register() : void {
		$instance = new self();

		// Filters.
		add_filter( 'wp_print_styles', array( $instance, 'remove_gutenberg_cruft' ), 100 );
		add_filter( 'sanitize_file_name', array( $instance, 'force_lowercase_filenames' ), 10, 1 );
		add_filter( 'should_load_separate_core_block_assets', '__return_true' ); // Optimize block resource loading.

		// Chunkier functions.
		$instance->remove_emoji_cruft();
		$instance->remove_head_cruft();
		$instance->disable_xmlrpc();
	}

	/**
	 * Disable XMLRPC functionality
	 *
	 * @return void
	 */
	private function disable_xmlrpc() : void {

		// Disable on the back end.
		add_filter( 'xmlrpc_enabled', '__return_false' );
		add_filter( 'pre_option_enable_xmlrpc', '__return_false' );

		// Disable the methods.
		add_filter(
			'xmlrpc_methods',
			function( $methods ) {
				unset( $methods['pingback.ping'] );
				unset( $methods['pingback.extensions.getPingbacks'] );
				return $methods;
			}
		);

		// Remove the header link.
		add_filter(
			'bloginfo_url',
			function( $output, $property ) {
				return ( $property == 'pingback_url' ) ? '#' : $output;
			},
			11,
			2
		);

		// Remove the HTTP header.
		add_filter(
			'wp',
			function() {
				header_remove( 'X-Pingback' );
			},
			9999
		);

	}

	/**
	 * Remove Gutenberg CSS
	 *
	 * @return void
	 */
	public function remove_gutenberg_cruft() : void {
		wp_deregister_style( 'wp-block-library' );
		wp_deregister_style( 'wp-block-library-theme' );
		wp_deregister_style( 'wp-block-library-css' );
		wp_deregister_style( 'wp-block-paragraph' );
		wp_deregister_style( 'classic-theme-styles' );
		wp_deregister_style( 'global-styles' );
		wp_dequeue_style( 'wp-block-library' );
		wp_dequeue_style( 'wp-block-library-theme' );
		wp_dequeue_style( 'wp-block-library-css' );
		wp_dequeue_style( 'classic-theme-styles' );
		wp_dequeue_style( 'wp-block-paragraph' );
		wp_dequeue_style( 'global-styles' );
	}

	/**
	 * Renames uploaded media to use lowercase URLs
	 *
	 * @param  string $filename The filename.
	 *
	 * @return string           The modified filename
	 */
	public function force_lowercase_filenames( $filename ) {
		$info = pathinfo( $filename );
		$ext  = empty( $info['extension'] ) ? '' : '.' . $info['extension'];
		$name = basename( $filename, $ext );
		return strtolower( $name ) . $ext;
	}

	/**
	 * Remove inline emoji scripts & styles
	 *
	 * @return void
	 */
	private function remove_emoji_cruft() : void {
		remove_action( 'wp_head', 'print_emoji_detection_script', 7 );
		remove_action( 'wp_print_styles', 'print_emoji_styles' );
		remove_action( 'admin_print_scripts', 'print_emoji_detection_script' );
		remove_action( 'admin_print_styles', 'print_emoji_styles' );
		remove_filter( 'the_content_feed', 'wp_staticize_emoji' );
		remove_filter( 'comment_text_rss', 'wp_staticize_emoji' );
		remove_filter( 'wp_mail', 'wp_staticize_emoji_for_email' );
		add_filter( 'wp_resource_hints', array( $this, 'remove_emoji_dns_prefetch' ), 10, 2 );
	}

	/**
	 * Removes some unused DNS prefetch hints
	 *
	 * @param  array  $hints         The hints.
	 *
	 * @param  string $relation_type The type of hint.
	 *
	 * @return array                 The modified hints
	 */
	public function remove_emoji_dns_prefetch( $hints, $relation_type ) {
		if ( 'dns-prefetch' === $relation_type ) {
			$matches = preg_grep( '/emoji/', $hints );
			return array_diff( $hints, $matches );
		}
		return $hints;
	}

	/**
	 * Disables pingback headers
	 *
	 * @param  array $headers  The headers.
	 *
	 * @return array           The modified headers
	 */
	public function remove_x_pingback( $headers ) {
		unset( $headers['X-Pingback'] );
		return $headers;
	}

	/**
	 * Removes cruft from the <head>
	 *
	 * @return void
	 */
	private function remove_head_cruft() : void {
		remove_action( 'wp', 'rsd_link', 9 );
		remove_action( 'wp_head', 'wlwmanifest_link' );
		remove_action( 'wp_head', 'wp_shortlink_wp_head', 10 );
		remove_action( 'wp_head', 'wp_generator' );
		remove_action( 'wp_head', 'feed_links', 2 );
		remove_action( 'wp_head', 'feed_links_extra', 3 );
		remove_action( 'wp_head', 'rest_output_link_wp_head', 10 );
		remove_action( 'template_redirect', 'rest_output_link_header', 11, 0 );
		remove_action( 'template_redirect', 'wp_shortlink_header', 11 );
		remove_action( 'wp_head', 'adjacent_posts_rel_link_wp_head' );
		add_filter( 'wp_headers', array( $this, 'remove_x_pingback' ), 10, 1 );
	}

}