<?php 
/** 
 * Post Meta source for the block bindings. 
 * 
 * @since 6.5.0 
 * @package WordPress 
 * @subpackage Block Bindings 
 */ 
 
/** 
 * Gets value for Post Meta source. 
 * 
 * @since 6.5.0 
 * @access private 
 * 
 * @param array    $source_args    Array containing source arguments used to look up the override value. 
 *                                 Example: array( "key" => "foo" ). 
 * @param WP_Block $block_instance The block instance. 
 * @return mixed The value computed for the source. 
 */ 
function _block_bindings_post_meta_get_value( array $source_args, $block_instance ) { 
    if ( empty( $source_args['key'] ) ) { 
        return null; 
    } 
 
    if ( empty( $block_instance->context['postId'] ) ) { 
        return null; 
    } 
    $post_id = $block_instance->context['postId']; 
 
    // If a post isn't public, we need to prevent unauthorized users from accessing the post meta. 
    $post = get_post( $post_id ); 
    if ( ( ! is_post_publicly_viewable( $post ) && ! current_user_can( 'read_post', $post_id ) ) || post_password_required( $post ) ) { 
        return null; 
    } 
 
    // Check if the meta field is protected. 
    if ( is_protected_meta( $source_args['key'], 'post' ) ) { 
        return null; 
    } 
 
    // Check if the meta field is registered to be shown in REST. 
    $meta_keys = get_registered_meta_keys( 'post', $block_instance->context['postType'] ); 
    // Add fields registered for all subtypes. 
    $meta_keys = array_merge( $meta_keys, get_registered_meta_keys( 'post', '' ) ); 
    if ( empty( $meta_keys[ $source_args['key'] ]['show_in_rest'] ) ) { 
        return null; 
    } 
 
    return get_post_meta( $post_id, $source_args['key'], true ); 
} 
 
/** 
 * Registers Post Meta source in the block bindings registry. 
 * 
 * @since 6.5.0 
 * @access private 
 */ 
function _register_block_bindings_post_meta_source() { 
    register_block_bindings_source( 
        'core/post-meta', 
        array( 
            'label'              => _x( 'Post Meta', 'block bindings source' ), 
            'get_value_callback' => '_block_bindings_post_meta_get_value', 
            'uses_context'       => array( 'postId', 'postType' ), 
        ) 
    ); 
} 
 
add_action( 'init', '_register_block_bindings_post_meta_source' ); 
 
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