domain_exists( string $domain, string $path, int $network_id = 1 ): int|null

Description

Compatibility

Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.

Parameters

$domainstring

The domain to be checked.

$pathstring

The path to be checked.

$network_idintoptional

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

Return value

int|null

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

Performance profile

How much work a call to domain_exists() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.

Cost class

Trivial

Touches nothing outside its own arguments.

Scaling

Constant

No loop in the body: the same number of instructions runs whatever you pass in.

Instructions

30

Executed per call on PHP 8.5. The body compiles to 30.

Plugin surface

1 hook

Third-party callbacks on 'domain_exists' run inside this call, and their cost is not bounded by anything here.

Called by

4

4 places in core call this, so the cost is paid more often than your own code shows.

What it touches

• hookthird-party callbacksapply_filters()called directly

What one call costs · 1 distinct outcome

One number would be a lie: the work depends on which branch runs. These are every distinct cost domain_exists() can have, taken from its control-flow graph on PHP 8.5.

Hooks and filters fired · 1

One hook fires while domain_exists() runs, in this order:

1. 1
   apply_filters( domain_exists )filterline 1635 (+26 into the body)

   Filters whether a site name is taken.

Uses · 3

• trailingslashit()Appends a trailing slash.
• get_sites()Retrieves a list of sites matching requested arguments.
• apply_filters()Calls the callback functions that have been added to a filter hook.

Used by · 4

• create_empty_blog()Create an empty blog.
• wp_validate_site_data()Validates data for a site prior to inserting or updating in the database.
• wpmu_create_blog()Creates a site.
• wpmu_validate_blog_signup()Processes new site registrations.

Source code

View on Trac ↗View on GitHub ↗

1609function domain_exists( $domain, $path, $network_id = 1 ) {1610	$path   = trailingslashit( $path );1611	$args   = array(1612		'network_id'             => $network_id,1613		'domain'                 => $domain,1614		'path'                   => $path,1615		'fields'                 => 'ids',1616		'number'                 => 1,1617		'update_site_meta_cache' => false,1618	);1619	$result = get_sites( $args );1620	$result = array_shift( $result );1621 1622	/**1623	 * Filters whether a site name is taken.1624	 *1625	 * The name is the site's subdomain or the site's subdirectory1626	 * path depending on the network settings.1627	 *1628	 * @since 3.5.01629	 *1630	 * @param int|null $result     The site ID if the site name exists, null otherwise.1631	 * @param string   $domain     Domain to be checked.1632	 * @param string   $path       Path to be checked.1633	 * @param int      $network_id Network ID. Only relevant on multi-network installations.1634	 */1635	return apply_filters( 'domain_exists', $result, $domain, $path, $network_id );1636}

Changelog

Introduced in MU (3.0.0). Unchanged from 6.7.7 through 7.1.0.

1. 6.7.7
2. 6.8.8
3. 6.9.7
4. 7.0.4
5. 7.1.0

Signature, return type and hooks compared across 5 parsed releases.

About this page

Parsed data

Generated from the wordpress-develop 7.1.0 tag, from src/wp-includes/ms-functions.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

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