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WP_Block_Metadata_Registry::default_identifier_callback( string $path ): string

Since
6.7.0
Source
wp-includes/class-wp-block-metadata-registry.php:288
Default identifier function to determine the block identifier from a given path.

Description

This function extracts the block identifier from the path:

  • For 'block.json' files, it uses the parent directory name.
  • For directories, it uses the directory name itself.
  • For empty paths, it returns an empty string.

For example:

  • Path: '/wp-content/plugins/my-plugin/blocks/example/block.json' Identifier: 'example'
  • Path: '/wp-content/plugins/my-plugin/blocks/another-block' Identifier: 'another-block'

This default behavior matches the standard WordPress block structure.

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

$pathstring
The normalized file or folder path to determine the block identifier from.

Return value

string
The block identifier, or an empty string if the path is empty.

Performance profile

How much work a call to WP_Block_Metadata_Registry::default_identifier_callback() 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
4–13

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 18.

Plugin surface
None

Nothing here hands control to plugin code.

Called by
1

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

What one call costs · 2 distinct outcomes

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

WhenInstructionsCalls it makes
empty($path)4none
!empty($path)12–13str_ends_with(), basename()

Across PHP versions

PHPCompiledExecutedBranchesNotes
8.6-dev184–132
8.5184–132
8.4184–1322 fewer instructions than PHP 8.3
8.3204–152
8.2204–152
8.1204–152
7.4204–152

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 · 1

Used by · 1

Source code

	private static function default_identifier_callback( $path ) {		// Ensure $path is not empty to prevent unexpected behavior.		if ( empty( $path ) ) {			return '';		} 		if ( str_ends_with( $path, 'block.json' ) ) {			// Return the parent directory name if it's a block.json file.			return basename( dirname( $path ) );		} 		// Otherwise, assume it's a directory and return its name.		return basename( $path );	}

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/class-wp-block-metadata-registry.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.
Corrections
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