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

Get 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

$domain

(string) (Required)

$path

(string) (Optional) Not required for subdomain installations.

Default value: '/'

Return

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

Source

File: wp-includes/ms-functions.php 

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 );
	$id     = array_shift( $result );

	if ( ! $id ) {
		wp_cache_set( md5( $domain . $path ), -1, 'blog-id-cache' );
		return 0;
	}

	wp_cache_set( md5( $domain . $path ), $id, 'blog-id-cache' );

	return $id;
}

Uses

Uses Description
wp-includes/ms-site.php: get_sites()

Retrieves a list of sites matching requested arguments.
wp-includes/cache.php: wp_cache_get()

Retrieves the cache contents from the cache by key and group.
wp-includes/cache.php: wp_cache_set()

Saves the data to the cache.

Changelog

Version Description
MU (3.0.0) Introduced.

© 2003–2019 WordPress Foundation
Licensed under the GNU GPLv2+ License.
https://developer.wordpress.org/reference/functions/get_blog_id_from_url