* Blocks API: WP_Block class
* Class representing a parsed instance of a block.
* @property array $attributes
#[AllowDynamicProperties]
* Original parsed array representation of block.
* @example "core/paragraph"
* Block type associated with the instance.
public $context = array();
* All available context of the current hierarchy.
protected $available_context;
* @var WP_Block_Type_Registry
* List of inner blocks (of this same class)
public $inner_blocks = array();
* Resultant HTML from inside block comment delimiters after removing inner
* @example "...Just <!-- wp:test /--> testing..." -> "Just testing..."
* List of string fragments and null markers where inner blocks were found
* 'inner_html' => 'BeforeInnerAfter',
* 'inner_blocks' => array( block, block ),
* 'inner_content' => array( 'Before', null, 'Inner', null, 'After' ),
public $inner_content = array();
* Populates object properties from the provided block instance argument.
* The given array of context values will not necessarily be available on
* the instance itself, but is treated as the full set of values provided by
* the block's ancestry. This is assigned to the private `available_context`
* property. Only values which are configured to consumed by the block via
* its registered type will be assigned to the block's `context` property.
* A representative array of a single parsed block object. See WP_Block_Parser_Block.
* @type string $blockName Name of block.
* @type array $attrs Attributes from block comment delimiters.
* @type array $innerBlocks List of inner blocks. An array of arrays that
* have the same structure as this one.
* @type string $innerHTML HTML from inside block comment delimiters.
* @type array $innerContent List of string fragments and null markers where inner blocks were found.
* @param array $available_context Optional array of ancestry context values.
* @param WP_Block_Type_Registry $registry Optional block type registry.
public function __construct( $block, $available_context = array(), $registry = null ) {
$this->parsed_block = $block;
$this->name = $block['blockName'];
if ( is_null( $registry ) ) {
$registry = WP_Block_Type_Registry::get_instance();
$this->registry = $registry;
$this->block_type = $registry->get_registered( $this->name );
$this->available_context = $available_context;
if ( ! empty( $this->block_type->uses_context ) ) {
foreach ( $this->block_type->uses_context as $context_name ) {
if ( array_key_exists( $context_name, $this->available_context ) ) {
$this->context[ $context_name ] = $this->available_context[ $context_name ];
if ( ! empty( $block['innerBlocks'] ) ) {
$child_context = $this->available_context;
if ( ! empty( $this->block_type->provides_context ) ) {
foreach ( $this->block_type->provides_context as $context_name => $attribute_name ) {
if ( array_key_exists( $attribute_name, $this->attributes ) ) {
$child_context[ $context_name ] = $this->attributes[ $attribute_name ];
$this->inner_blocks = new WP_Block_List( $block['innerBlocks'], $child_context, $registry );
if ( ! empty( $block['innerHTML'] ) ) {
$this->inner_html = $block['innerHTML'];
if ( ! empty( $block['innerContent'] ) ) {
$this->inner_content = $block['innerContent'];
* Returns a value from an inaccessible property.
* This is used to lazily initialize the `attributes` property of a block,
* such that it is only prepared with default attributes at the time that
* the property is accessed. For all other inaccessible properties, a `null`
* @param string $name Property name.
* @return array|null Prepared attributes, or null.
public function __get( $name ) {
if ( 'attributes' === $name ) {
$this->attributes = isset( $this->parsed_block['attrs'] ) ?
$this->parsed_block['attrs'] :
if ( ! is_null( $this->block_type ) ) {
$this->attributes = $this->block_type->prepare_attributes_for_render( $this->attributes );
return $this->attributes;
* Processes the block bindings and updates the block attributes with the values from the sources.
* A block might contain bindings in its attributes. Bindings are mappings
* between an attribute of the block and a source. A "source" is a function
* registered with `register_block_bindings_source()` that defines how to
* retrieve a value from outside the block, e.g. from post meta.
* This function will process those bindings and update the block's attributes
* with the values coming from the bindings.
* The "bindings" property for an Image block might look like this:
* "source": "core/post-meta",
* "args": { "key": "text_custom_field" }
* "source": "core/post-meta",
* "args": { "key": "url_custom_field" }
* The above example will replace the `title` and `url` attributes of the Image
* block with the values of the `text_custom_field` and `url_custom_field` post meta.
* @since 6.6.0 Handle the `__default` attribute for pattern overrides.
* @return array The computed block attributes for the provided block bindings.
private function process_block_bindings() {
$parsed_block = $this->parsed_block;
$computed_attributes = array();
$supported_block_attributes = array(
'core/paragraph' => array( 'content' ),
'core/heading' => array( 'content' ),
'core/image' => array( 'id', 'url', 'title', 'alt' ),
'core/button' => array( 'url', 'text', 'linkTarget', 'rel' ),
// If the block doesn't have the bindings property, isn't one of the supported
// block types, or the bindings property is not an array, return the block content.
! isset( $supported_block_attributes[ $this->name ] ) ||
empty( $parsed_block['attrs']['metadata']['bindings'] ) ||
! is_array( $parsed_block['attrs']['metadata']['bindings'] )
return $computed_attributes;
$bindings = $parsed_block['attrs']['metadata']['bindings'];
* If the default binding is set for pattern overrides, replace it
* with a pattern override binding for all supported attributes.
isset( $bindings['__default']['source'] ) &&
'core/pattern-overrides' === $bindings['__default']['source']
$updated_bindings = array();
* Build a binding array of all supported attributes.
* Note that this also omits the `__default` attribute from the
foreach ( $supported_block_attributes[ $parsed_block['blockName'] ] as $attribute_name ) {
// Retain any non-pattern override bindings that might be present.
$updated_bindings[ $attribute_name ] = isset( $bindings[ $attribute_name ] )
? $bindings[ $attribute_name ]
: array( 'source' => 'core/pattern-overrides' );
$bindings = $updated_bindings;
foreach ( $bindings as $attribute_name => $block_binding ) {
// If the attribute is not in the supported list, process next attribute.
if ( ! in_array( $attribute_name, $supported_block_attributes[ $this->name ], true ) ) {
// If no source is provided, or that source is not registered, process next attribute.
if ( ! isset( $block_binding['source'] ) || ! is_string( $block_binding['source'] ) ) {
$block_binding_source = get_block_bindings_source( $block_binding['source'] );
if ( null === $block_binding_source ) {
$source_args = ! empty( $block_binding['args'] ) && is_array( $block_binding['args'] ) ? $block_binding['args'] : array();
$source_value = $block_binding_source->get_value( $source_args, $this, $attribute_name );
// If the value is not null, process the HTML based on the block and the attribute.
if ( ! is_null( $source_value ) ) {
$computed_attributes[ $attribute_name ] = $source_value;
return $computed_attributes;
* Depending on the block attribute name, replace its value in the HTML based on the value provided.
* @param string $block_content Block content.
* @param string $attribute_name The attribute name to replace.
* @param mixed $source_value The value used to replace in the HTML.
* @return string The modified block content.
private function replace_html( string $block_content, string $attribute_name, $source_value ) {
$block_type = $this->block_type;
if ( ! isset( $block_type->attributes[ $attribute_name ]['source'] ) ) {
// Depending on the attribute source, the processing will be different.
switch ( $block_type->attributes[ $attribute_name ]['source'] ) {
$block_reader = new WP_HTML_Tag_Processor( $block_content );
// TODO: Support for CSS selectors whenever they are ready in the HTML API.
// In the meantime, support comma-separated selectors by exploding them into an array.
$selectors = explode( ',', $block_type->attributes[ $attribute_name ]['selector'] );
// Add a bookmark to the first tag to be able to iterate over the selectors.
$block_reader->next_tag();
$block_reader->set_bookmark( 'iterate-selectors' );
// TODO: This shouldn't be needed when the `set_inner_html` function is ready.
// Store the parent tag and its attributes to be able to restore them later in the button.
// The button block has a wrapper while the paragraph and heading blocks don't.
if ( 'core/button' === $this->name ) {
$button_wrapper = $block_reader->get_tag();
$button_wrapper_attribute_names = $block_reader->get_attribute_names_with_prefix( '' );
$button_wrapper_attrs = array();
foreach ( $button_wrapper_attribute_names as $name ) {
$button_wrapper_attrs[ $name ] = $block_reader->get_attribute( $name );
foreach ( $selectors as $selector ) {
// If the parent tag, or any of its children, matches the selector, replace the HTML.
if ( strcasecmp( $block_reader->get_tag( $selector ), $selector ) === 0 || $block_reader->next_tag(
$block_reader->release_bookmark( 'iterate-selectors' );
// TODO: Use `set_inner_html` method whenever it's ready in the HTML API.
// Until then, it is hardcoded for the paragraph, heading, and button blocks.
// Store the tag and its attributes to be able to restore them later.
$selector_attribute_names = $block_reader->get_attribute_names_with_prefix( '' );
$selector_attrs = array();
foreach ( $selector_attribute_names as $name ) {
$selector_attrs[ $name ] = $block_reader->get_attribute( $name );
$selector_markup = "<$selector>" . wp_kses_post( $source_value ) . "</$selector>";
$amended_content = new WP_HTML_Tag_Processor( $selector_markup );
$amended_content->next_tag();
foreach ( $selector_attrs as $attribute_key => $attribute_value ) {
$amended_content->set_attribute( $attribute_key, $attribute_value );
if ( 'core/paragraph' === $this->name || 'core/heading' === $this->name ) {
return $amended_content->get_updated_html();
if ( 'core/button' === $this->name ) {
$button_markup = "<$button_wrapper>{$amended_content->get_updated_html()}</$button_wrapper>";
$amended_button = new WP_HTML_Tag_Processor( $button_markup );
$amended_button->next_tag();
foreach ( $button_wrapper_attrs as $attribute_key => $attribute_value ) {
$amended_button->set_attribute( $attribute_key, $attribute_value );
return $amended_button->get_updated_html();
$block_reader->seek( 'iterate-selectors' );
$block_reader->release_bookmark( 'iterate-selectors' );
$amended_content = new WP_HTML_Tag_Processor( $block_content );
if ( ! $amended_content->next_tag(
// TODO: build the query from CSS selector.
'tag_name' => $block_type->attributes[ $attribute_name ]['selector'],
$amended_content->set_attribute( $block_type->attributes[ $attribute_name ]['attribute'], $source_value );
return $amended_content->get_updated_html();
* Generates the render output for the block.
* @since 6.5.0 Added block bindings processing.
* @global WP_Post $post Global post object.
* @param array $options {
* Optional options object.
* @type bool $dynamic Defaults to 'true'. Optionally set to false to avoid using the block's render_callback.
* @return string Rendered block output.
public function render( $options = array() ) {
* There can be only one root interactive block at a time because the rendered HTML of that block contains
* the rendered HTML of all its inner blocks, including any interactive block.
static $root_interactive_block = null;
* Filters whether Interactivity API should process directives.
* @param bool $enabled Whether the directives processing is enabled.
$interactivity_process_directives_enabled = apply_filters( 'interactivity_process_directives', true );
$interactivity_process_directives_enabled && null === $root_interactive_block && (
( isset( $this->block_type->supports['interactivity'] ) && true === $this->block_type->supports['interactivity'] ) ||
! empty( $this->block_type->supports['interactivity']['interactive'] )
$root_interactive_block = $this;
$options = wp_parse_args(
// Process the block bindings and get attributes updated with the values from the sources.
$computed_attributes = $this->process_block_bindings();
if ( ! empty( $computed_attributes ) ) {
// Merge the computed attributes with the original attributes.
$this->attributes = array_merge( $this->attributes, $computed_attributes );
$is_dynamic = $options['dynamic'] && $this->name && null !== $this->block_type && $this->block_type->is_dynamic();
if ( ! $options['dynamic'] || empty( $this->block_type->skip_inner_blocks ) ) {
foreach ( $this->inner_content as $chunk ) {
if ( is_string( $chunk ) ) {
$block_content .= $chunk;
$inner_block = $this->inner_blocks[ $index ];
/** This filter is documented in wp-includes/blocks.php */
$pre_render = apply_filters( 'pre_render_block', null, $inner_block->parsed_block, $parent_block );
if ( ! is_null( $pre_render ) ) {
$block_content .= $pre_render;
$source_block = $inner_block->parsed_block;
/** This filter is documented in wp-includes/blocks.php */
$inner_block->parsed_block = apply_filters( 'render_block_data', $inner_block->parsed_block, $source_block, $parent_block );
/** This filter is documented in wp-includes/blocks.php */
$inner_block->context = apply_filters( 'render_block_context', $inner_block->context, $inner_block->parsed_block, $parent_block );
$block_content .= $inner_block->render();
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