get_blog_id_from_url( string $domain, string $path = '/' ): int

Gets a blog’s numeric ID from its URL.

Description

On a subdirectory installation like example.com/blog1/, $domain will be the root ‘example.com’ and $path the subdirectory ‘/blog1/’. With subdomains like blog1.example.com, $domain is ‘blog1.example.com’ and $path is ‘/’.

Parameters

$domainstringrequired
Website domain.
$pathstringoptional
Not required for subdomain installations. Default '/'.

Default:'/'

Return

int 0 if no blog found, otherwise the ID of the matching blog.

Source

 * subdirectory '/blog1/'. With subdomains like blog1.example.com,
 * $domain is 'blog1.example.com' and $path is '/'.
 *
 * @since MU (3.0.0)
 *
 * @global wpdb $wpdb WordPress database abstraction object.
 *
 * @param string $domain Website domain.
 * @param string $path   Optional. Not required for subdomain installations. Default '/'.
 * @return int 0 if no blog found, otherwise the ID of the matching blog.
 */
function get_blog_id_from_url( $domain, $path = '/' ) {
	$domain = strtolower( $domain );
	$path   = strtolower( $path );
	$id     = wp_cache_get( md5( $domain . $path ), 'blog-id-cache' );

	if ( -1 === $id ) { // Blog does not exist.
		return 0;
	} elseif ( $id ) {
		return (int) $id;
	}

	$args   = array(
		'domain'                 => $domain,
		'path'                   => $path,
		'fields'                 => 'ids',
		'number'                 => 1,
		'update_site_meta_cache' => false,
	);
	$result = get_sites( $args );

Changelog

VersionDescription
MU (3.0.0)Introduced.

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