domain_exists() │ WP 3.0.0

Checks whether a site name is already taken.

The name is the site's subdomain or the site's subdirectory path depending on the network settings.

Used during the new site registration process to ensure that each site name is unique.

Return

Int|null. The site ID if the site name exists, null otherwise.

Usage

domain_exists( $domain, $path, $network_id );

$domain(string) (required)

The domain to be checked.

$path(string) (required)

The path to be checked.

$network_id(int)

Network ID. Only relevant on multi-network installations.
Default: 1

Changelog

domain_exists() domain exists code ^{WP 6.5.2}

function domain_exists( $domain, $path, $network_id = 1 ) {
	$path   = trailingslashit( $path );
	$args   = array(
		'network_id'             => $network_id,
		'domain'                 => $domain,
		'path'                   => $path,
		'fields'                 => 'ids',
		'number'                 => 1,
		'update_site_meta_cache' => false,
	);
	$result = get_sites( $args );
	$result = array_shift( $result );

	/**
	 * Filters whether a site name is taken.
	 *
	 * The name is the site's subdomain or the site's subdirectory
	 * path depending on the network settings.
	 *
	 * @since 3.5.0
	 *
	 * @param int|null $result     The site ID if the site name exists, null otherwise.
	 * @param string   $domain     Domain to be checked.
	 * @param string   $path       Path to be checked.
	 * @param int      $network_id Network ID. Only relevant on multi-network installations.
	 */
	return apply_filters( 'domain_exists', $result, $domain, $path, $network_id );
}