404 page temple for the Genesis Framework. Includes a test for the Yoast SEO plugin in order to alter the page title.

404.php

<?php
/*
Template Name: Error 404
*/

/**
 * Handles the display of website 404 page. Includes a widget area for easy customization.
 *
 * @author   B3Marketing, LLC — Rick R. Duncan
 * @license  http://www.opensource.org/licenses/gpl-license.php GPL v2.0 (or later)
 * @link     http://www.digitalredeye.com
 */


// Add Noindex tag to the page
add_action( 'genesis_meta', 'b3m_noindex_page' );
function b3m_noindex_page() {
  echo '<meta name="robots" content="noindex, follow">';
}

// Add canonical tag to the page
add_action( 'genesis_meta', 'b3m_canonical' );
function b3m_canonical() {
	echo '<link rel="canonical" href="'.get_site_url().'/404" />';
}

// Output <title> tag. Test for Yoast SEO Plugin
function b3m_set_page_title($orig_title) {
	$title = 'Error 404: File Not Found';
	return $title;
}
if ( genesis_detect_seo_plugins(array('wpSEO')) ) {
		add_filter('wpseo_title', 'b3m_set_page_title');
	}
	else {
		add_filter('wp_title', 'b3m_set_page_title');
	}



// Remove default loop
remove_action( 'genesis_loop', 'genesis_do_loop' );

add_action( 'genesis_loop', 'custom_genesis_404' );
function custom_genesis_404() { ?>
	<div class="page hentry">
		<h1 class="entry-title"><?php _e( 'Error 404: File Not Found', 'genesis' ); ?></h1>
		<div class="entry-content">
			<?php
			if ( is_active_sidebar( '404-page' ) ) {
				echo '<div class="entry-content">';
				dynamic_sidebar( '404-page' );
				echo '</div><!-- end .entry-content -->';		
			}
			else {
				genesis_standard_loop();
			}
			?>
		</div><!-- end .entry-content -->
	</div><!-- end .pageclass -->
<?php }
genesis();