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WordPress

user_can_for_site( int|WP_User $user, int $site_id, string $capability, mixed $args ): bool

Since
6.7.0
Source
wp-includes/capabilities.php:1045
Returns whether a particular user has the specified capability for a given site.

Description

This function also accepts an ID of an object to check against if the capability is a meta capability. Meta capabilities such as edit_post and edit_user are capabilities used by the map_meta_cap() function to map to primitive capabilities that a user or role has, such as edit_posts and edit_others_posts.

Example usage:

user_can_for_site( $user->ID, $site_id, 'edit_posts' );
user_can_for_site( $user->ID, $site_id, 'edit_post', $post->ID );
user_can_for_site( $user->ID, $site_id, 'edit_post_meta', $post->ID, $meta_key );

Compatibility

WordPress
since 6.7.0
PHP
7.4–8.6-dev
  • 6.7.7
  • 6.8.8
  • 6.9.7
  • 7.0.4
  • 7.1.0

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

Parameters

$userint|WP_User
User ID or object.
$site_idint
Site ID.
$capabilitystring
Capability name.
$argsmixed
Optional further parameters, typically starting with an object ID.

Return value

bool
Whether the user has the given capability.

Performance profile

How much work a call to user_can_for_site() 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
Heavy

Reaches the database via get_user_by().

Scaling
Constant

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

Instructions
11–47

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 49.

Plugin surface
None

Nothing here hands control to plugin code.

Called by
0

Nothing in core calls this; the cost is only what you spend yourself.

What it touches

  • querycontent queryget_user_by()one call below user_can_for_site()
  • hookthird-party callbacksdo_action()one call below user_can_for_site()
  • cacheobject cachewp_cache_switch_to_blog()one call below user_can_for_site()

What one call costs · 20 distinct outcomes

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

WhenInstructionsCalls it makes
is_object($user) && !empty($user)11–13none
!is_object($user) && !empty($user)15–17get_userdata()
is_object($user) && empty($user)20–22->init()
!is_object($user) && empty($user)24–26get_userdata(), ->init()
is_object($user) && !empty($user) && !is_multisite()28is_multisite(), user_can()
is_object($user) && !empty($user) && !is_multisite()30is_multisite(), user_can(), restore_current_blog()
is_object($user) && !empty($user) && is_multisite()32is_multisite(), switch_to_blog(), user_can()
!is_object($user) && !empty($user) && !is_multisite()32get_userdata(), is_multisite(), user_can()
is_object($user) && !empty($user) && is_multisite()34is_multisite(), switch_to_blog(), user_can(), restore_current_blog()
!is_object($user) && !empty($user) && !is_multisite()34get_userdata(), is_multisite(), user_can(), restore_current_blog()
!is_object($user) && !empty($user) && is_multisite()36get_userdata(), is_multisite(), switch_to_blog(), user_can()
is_object($user) && empty($user) && !is_multisite()37->init(), is_multisite(), user_can()
8 further outcomes, up to 47 instructions
!is_object($user) && !empty($user) && is_multisite()38get_userdata(), is_multisite(), switch_to_blog(), user_can(), restore_current_blog()
is_object($user) && empty($user) && !is_multisite()39->init(), is_multisite(), user_can(), restore_current_blog()
is_object($user) && empty($user) && is_multisite()41->init(), is_multisite(), switch_to_blog(), user_can()
!is_object($user) && empty($user) && !is_multisite()41get_userdata(), ->init(), is_multisite(), user_can()
is_object($user) && empty($user) && is_multisite()43->init(), is_multisite(), switch_to_blog(), user_can(), restore_current_blog()
!is_object($user) && empty($user) && !is_multisite()43get_userdata(), ->init(), is_multisite(), user_can(), restore_current_blog()
!is_object($user) && empty($user) && is_multisite()45get_userdata(), ->init(), is_multisite(), switch_to_blog(), user_can()
!is_object($user) && empty($user) && is_multisite()47get_userdata(), ->init(), is_multisite(), switch_to_blog(), user_can(), restore_current_blog()

Across PHP versions

PHPCompiledExecutedBranchesNotes
8.6-dev4811–4661 fewer instruction than PHP 8.5
8.54911–476
8.44911–4762 fewer instructions than PHP 8.3
8.35113–496
8.25113–496
8.15113–4961 more instruction than PHP 7.4
7.45013–486

An instruction is not a fixed amount of time, so a matching count is not necessarily the same speed; what it rules out is a difference in the work itself.

Uses · 7

Source code

View on Trac View on GitHub 

function user_can_for_site( $user, $site_id, $capability, ...$args ) {	if ( ! is_object( $user ) ) {		$user = get_userdata( $user );	} 	if ( empty( $user ) ) {		// User is logged out, create anonymous user object.		$user = new WP_User( 0 );		$user->init( new stdClass() );	} 	// Check if the blog ID is valid.	if ( ! is_numeric( $site_id ) || $site_id <= 0 ) {		return false;	} 	$switched = is_multisite() ? switch_to_blog( $site_id ) : false; 	$can = user_can( $user->ID, $capability, ...$args ); 	if ( $switched ) {		restore_current_blog();	} 	return $can;}

Changelog

Introduced in 6.7.0. 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/capabilities.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.
Corrections
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