<?php
/**
* Block Bindings API: WP_Block_Bindings_Registry class.
*
* Supports overriding content in blocks by connecting them to different sources.
*
* @package WordPress
* @subpackage Block Bindings
* @since 6.5.0
*/
/**
* Core class used for interacting with block bindings sources.
*
* @since 6.5.0
*/
final class WP_Block_Bindings_Registry {
/**
* Holds the registered block bindings sources, keyed by source identifier.
*
* @since 6.5.0
* @var WP_Block_Bindings_Source[]
*/
private $sources = array();
/**
* Container for the main instance of the class.
*
* @since 6.5.0
* @var WP_Block_Bindings_Registry|null
*/
private static $instance = null;
/**
* Supported source properties that can be passed to the registered source.
*
* @since 6.5.0
* @var string[]
*/
private $allowed_source_properties = array(
'label',
'get_value_callback',
'uses_context',
);
/**
* Supported blocks that can use the block bindings API.
*
* @since 6.5.0
* @var string[]
*/
private $supported_blocks = array(
'core/paragraph',
'core/heading',
'core/image',
'core/button',
);
/**
* Registers a new block bindings source.
*
* This is a low-level method. For most use cases, it is recommended to use
* the `register_block_bindings_source()` function instead.
*
* @see register_block_bindings_source()
*
* Sources are used to override block's original attributes with a value
* coming from the source. Once a source is registered, it can be used by a
* block by setting its `metadata.bindings` attribute to a value that refers
* to the source.
*
* @since 6.5.0
*
* @param string $source_name The name of the source. It must be a string containing a namespace prefix, i.e.
* `my-plugin/my-custom-source`. It must only contain lowercase alphanumeric
* characters, the forward slash `/` and dashes.
* @param array $source_properties {
* The array of arguments that are used to register a source.
*
* @type string $label The label of the source.
* @type callable $get_value_callback A callback executed when the source is processed during block rendering.
* The callback should have the following signature:
*
* `function( $source_args, $block_instance, $attribute_name ): mixed`
* - @param array $source_args Array containing source arguments
* used to look up the override value,
* i.e. {"key": "foo"}.
* - @param WP_Block $block_instance The block instance.
* - @param string $attribute_name The name of the target attribute.
* The callback has a mixed return type; it may return a string to override
* the block's original value, null, false to remove an attribute, etc.
* @type string[] $uses_context Optional. Array of values to add to block `uses_context` needed by the source.
* }
* @return WP_Block_Bindings_Source|false Source when the registration was successful, or `false` on failure.
*/
public function register( string $source_name, array $source_properties ) {
if ( ! is_string( $source_name ) ) {
_doing_it_wrong(
__METHOD__,
__( 'Block bindings source name must be a string.' ),
'6.5.0'
);
return false;
}
if ( preg_match( '/[A-Z]+/', $source_name ) ) {
_doing_it_wrong(
__METHOD__,
__( 'Block bindings source names must not contain uppercase characters.' ),
'6.5.0'
);
return false;
}
$name_matcher = '/^[a-z0-9-]+\/[a-z0-9-]+$/';
if ( ! preg_match( $name_matcher, $source_name ) ) {
_doing_it_wrong(
__METHOD__,
__( 'Block bindings source names must contain a namespace prefix. Example: my-plugin/my-custom-source' ),
'6.5.0'
);
return false;
}
if ( $this->is_registered( $source_name ) ) {
_doing_it_wrong(
__METHOD__,
/* translators: %s: Block bindings source name. */
sprintf( __( 'Block bindings source "%s" already registered.' ), $source_name ),
'6.5.0'
);
return false;
}
// Validates that the source properties contain the label.
if ( ! isset( $source_properties['label'] ) ) {
_doing_it_wrong(
__METHOD__,
__( 'The $source_properties must contain a "label".' ),
'6.5.0'
);
return false;
}
// Validates that the source properties contain the get_value_callback.
if ( ! isset( $source_properties['get_value_callback'] ) ) {
_doing_it_wrong(
__METHOD__,
__( 'The $source_properties must contain a "get_value_callback".' ),
'6.5.0'
);
return false;
}
// Validates that the get_value_callback is a valid callback.
if ( ! is_callable( $source_properties['get_value_callback'] ) ) {
_doing_it_wrong(
__METHOD__,
__( 'The "get_value_callback" parameter must be a valid callback.' ),
'6.5.0'
);
return false;
}
// Validates that the uses_context parameter is an array.
if ( isset( $source_properties['uses_context'] ) && ! is_array( $source_properties['uses_context'] ) ) {
_doing_it_wrong(
__METHOD__,
__( 'The "uses_context" parameter must be an array.' ),
'6.5.0'
);
return false;
}
if ( ! empty( array_diff( array_keys( $source_properties ), $this->allowed_source_properties ) ) ) {
_doing_it_wrong(
__METHOD__,
__( 'The $source_properties array contains invalid properties.' ),
'6.5.0'
);
return false;
}
$source = new WP_Block_Bindings_Source(
$source_name,
$source_properties
);
$this->sources[ $source_name ] = $source;
// Adds `uses_context` defined by block bindings sources.
add_filter(
'get_block_type_uses_context',
function ( $uses_context, $block_type ) use ( $source ) {
if ( ! in_array( $block_type->name, $this->supported_blocks, true ) || empty( $source->uses_context ) ) {
return $uses_context;
}
// Use array_values to reset the array keys.
return array_values( array_unique( array_merge( $uses_context, $source->uses_context ) ) );
},
10,
2
);
return $source;
}
/**
* Unregisters a block bindings source.
*
* @since 6.5.0
*
* @param string $source_name Block bindings source name including namespace.
* @return WP_Block_Bindings_Source|false The unregistered block bindings source on success and `false` otherwise.
*/
public function unregister( string $source_name ) {
if ( ! $this->is_registered( $source_name ) ) {
_doing_it_wrong(
__METHOD__,
/* translators: %s: Block bindings source name. */
sprintf( __( 'Block binding "%s" not found.' ), $source_name ),
'6.5.0'
);
return false;
}
$unregistered_source = $this->sources[ $source_name ];
unset( $this->sources[ $source_name ] );
return $unregistered_source;
}
/**
* Retrieves the list of all registered block bindings sources.
*
* @since 6.5.0
*
* @return WP_Block_Bindings_Source[] The array of registered sources.
*/
public function get_all_registered() {
return $this->sources;
}
/**
* Retrieves a registered block bindings source.
*
* @since 6.5.0
*
* @param string $source_name The name of the source.
* @return WP_Block_Bindings_Source|null The registered block bindings source, or `null` if it is not registered.
*/
public function get_registered( string $source_name ) {
if ( ! $this->is_registered( $source_name ) ) {
return null;
}
return $this->sources[ $source_name ];
}
/**
* Checks if a block bindings source is registered.
*
* @since 6.5.0
*
* @param string $source_name The name of the source.
* @return bool `true` if the block bindings source is registered, `false` otherwise.
*/
public function is_registered( $source_name ) {
return isset( $this->sources[ $source_name ] );
}
/**
* Wakeup magic method.
*
* @since 6.5.0
*/
public function __wakeup() {
if ( ! $this->sources ) {
return;
}
if ( ! is_array( $this->sources ) ) {
throw new UnexpectedValueException();
}
foreach ( $this->sources as $value ) {
if ( ! $value instanceof WP_Block_Bindings_Source ) {
throw new UnexpectedValueException();
}
}
}
/**
* Utility method to retrieve the main instance of the class.
*
* The instance will be created if it does not exist yet.
*
* @since 6.5.0
*
* @return WP_Block_Bindings_Registry The main instance.
*/
public static function get_instance() {
if ( null === self::$instance ) {
self::$instance = new self();
}
return self::$instance;
}
}