wp_robots │ filter-hook │ WP 5.7.0

Allows you to add or remove robots meta tag directives.

The robots meta tag is output in the HEAD section of the page. For example:

<meta name='robots' content='directive, directive'>

<!-- for example -->
<meta name='robots' content='noindex, follow, max-image-preview:large' />

If the filter produces an empty array (the function returns an empty array), the robots meta tag is not output.

Usage

add_filter( 'wp_robots', 'wp_kama_robots_filter' );

/**
 * Function for `wp_robots` filter-hook.
 * 
 * @param array $robots Associative array of directives. Every key must be the name of the
 *                      directive, and the corresponding value must either be a string to provide as
 *                      value for the directive or a boolean `true` if it is a boolean directive,
 *                      i.e. without a value.
 *
 * @return array
 */
function wp_kama_robots_filter( $robots ){
	// filter...
	return $robots;
}

$robots(array)

Associative array of [ directive => value ] pairs. The key contains the directive name. The value can be a string for a directive with a value, or true for a boolean directive without a value.

Examples

#1 Prevent various site pages from being indexed

add_filter( 'wp_robots', 'wp_kama_robots_tag' );

function wp_kama_robots_tag( $robots ){

	// Prevent attachment, pagination, and post type archive pages from being indexed.
	if(
		is_attachment() ||
		is_paged() ||
		is_post_type_archive()
	){
		$robots['noindex'] = true;
	}

	// Prevent taxonomies from being indexed when their terms have no description.
	if(
		( is_category() || is_tag() || is_tax() )
		&& ! trim( get_queried_object()->description )
	){
		$robots['noindex'] = true;
	}

	// Prevent pages with the ?filter query parameter from being indexed.
	if( isset( $_GET['filter'] ) )
		$robots['none'] = true;

	return $robots;
}

#2 Remove existing directives

Suppose a plugin prevents pages from being indexed even though they should be indexed. This corrects the behavior:

add_filter( 'wp_robots', 'wp_kama_robots_tag' );

function wp_kama_robots_tag( $robots ){

	// Remove the unwanted directive.
	unset( $robots['noindex'] );

	return $robots;
}