Title: WP_REST_Block_Renderer_Controller
Published: December 6, 2018
Last modified: February 24, 2026

---

# class WP_REST_Block_Renderer_Controller {}

## In this article

 * [Description](https://developer.wordpress.org/reference/classes/wp_rest_block_renderer_controller/?output_format=md#description)
    - [See also](https://developer.wordpress.org/reference/classes/wp_rest_block_renderer_controller/?output_format=md#see-also)
 * [Methods](https://developer.wordpress.org/reference/classes/wp_rest_block_renderer_controller/?output_format=md#methods)
 * [Source](https://developer.wordpress.org/reference/classes/wp_rest_block_renderer_controller/?output_format=md#source)
 * [Related](https://developer.wordpress.org/reference/classes/wp_rest_block_renderer_controller/?output_format=md#related)
 * [Changelog](https://developer.wordpress.org/reference/classes/wp_rest_block_renderer_controller/?output_format=md#changelog)

[ Back to top](https://developer.wordpress.org/reference/classes/wp_rest_block_renderer_controller/?output_format=md#wp--skip-link--target)

Controller which provides REST endpoint for rendering a block.

## 󠀁[Description](https://developer.wordpress.org/reference/classes/wp_rest_block_renderer_controller/?output_format=md#description)󠁿

### 󠀁[See also](https://developer.wordpress.org/reference/classes/wp_rest_block_renderer_controller/?output_format=md#see-also)󠁿

 * [WP_REST_Controller](https://developer.wordpress.org/reference/classes/wp_rest_controller/)

## 󠀁[Methods](https://developer.wordpress.org/reference/classes/wp_rest_block_renderer_controller/?output_format=md#methods)󠁿

| Name | Description | 
| [WP_REST_Block_Renderer_Controller::__construct](https://developer.wordpress.org/reference/classes/wp_rest_block_renderer_controller/__construct/) | Constructs the controller. | 
| [WP_REST_Block_Renderer_Controller::get_item](https://developer.wordpress.org/reference/classes/wp_rest_block_renderer_controller/get_item/) | Returns block output from block’s registered render_callback. | 
| [WP_REST_Block_Renderer_Controller::get_item_permissions_check](https://developer.wordpress.org/reference/classes/wp_rest_block_renderer_controller/get_item_permissions_check/) | Checks if a given request has access to read blocks. | 
| [WP_REST_Block_Renderer_Controller::get_item_schema](https://developer.wordpress.org/reference/classes/wp_rest_block_renderer_controller/get_item_schema/) | Retrieves block’s output schema, conforming to JSON Schema. | 
| [WP_REST_Block_Renderer_Controller::register_routes](https://developer.wordpress.org/reference/classes/wp_rest_block_renderer_controller/register_routes/) | Registers the necessary REST API routes, one for each dynamic block. |

## 󠀁[Source](https://developer.wordpress.org/reference/classes/wp_rest_block_renderer_controller/?output_format=md#source)󠁿

    ```php
    class WP_REST_Block_Renderer_Controller extends WP_REST_Controller {

    	/**
    	 * Constructs the controller.
    	 *
    	 * @since 5.0.0
    	 */
    	public function __construct() {
    		$this->namespace = 'wp/v2';
    		$this->rest_base = 'block-renderer';
    	}

    	/**
    	 * Registers the necessary REST API routes, one for each dynamic block.
    	 *
    	 * @since 5.0.0
    	 *
    	 * @see register_rest_route()
    	 */
    	public function register_routes() {
    		register_rest_route(
    			$this->namespace,
    			'/' . $this->rest_base . '/(?P<name>[a-z0-9-]+/[a-z0-9-]+)',
    			array(
    				'args'   => array(
    					'name' => array(
    						'description' => __( 'Unique registered name for the block.' ),
    						'type'        => 'string',
    					),
    				),
    				array(
    					'methods'             => array( WP_REST_Server::READABLE, WP_REST_Server::CREATABLE ),
    					'callback'            => array( $this, 'get_item' ),
    					'permission_callback' => array( $this, 'get_item_permissions_check' ),
    					'args'                => array(
    						'context'    => $this->get_context_param( array( 'default' => 'view' ) ),
    						'attributes' => array(
    							'description'       => __( 'Attributes for the block.' ),
    							'type'              => 'object',
    							'default'           => array(),
    							'validate_callback' => static function ( $value, $request ) {
    								$block = WP_Block_Type_Registry::get_instance()->get_registered( $request['name'] );

    								if ( ! $block ) {
    									// This will get rejected in ::get_item().
    									return true;
    								}

    								$schema = array(
    									'type'                 => 'object',
    									'properties'           => $block->get_attributes(),
    									'additionalProperties' => false,
    								);

    								return rest_validate_value_from_schema( $value, $schema );
    							},
    							'sanitize_callback' => static function ( $value, $request ) {
    								$block = WP_Block_Type_Registry::get_instance()->get_registered( $request['name'] );

    								if ( ! $block ) {
    									// This will get rejected in ::get_item().
    									return true;
    								}

    								$schema = array(
    									'type'                 => 'object',
    									'properties'           => $block->get_attributes(),
    									'additionalProperties' => false,
    								);

    								return rest_sanitize_value_from_schema( $value, $schema );
    							},
    						),
    						'post_id'    => array(
    							'description' => __( 'ID of the post context.' ),
    							'type'        => 'integer',
    						),
    					),
    				),
    				'schema' => array( $this, 'get_public_item_schema' ),
    			)
    		);
    	}

    	/**
    	 * Checks if a given request has access to read blocks.
    	 *
    	 * @since 5.0.0
    	 *
    	 * @global WP_Post $post Global post object.
    	 *
    	 * @param WP_REST_Request $request Request.
    	 * @return true|WP_Error True if the request has read access, WP_Error object otherwise.
    	 */
    	public function get_item_permissions_check( $request ) {
    		global $post;

    		$post_id = isset( $request['post_id'] ) ? (int) $request['post_id'] : 0;

    		if ( $post_id > 0 ) {
    			$post = get_post( $post_id );

    			if ( ! $post || ! current_user_can( 'edit_post', $post->ID ) ) {
    				return new WP_Error(
    					'block_cannot_read',
    					__( 'Sorry, you are not allowed to read blocks of this post.' ),
    					array(
    						'status' => rest_authorization_required_code(),
    					)
    				);
    			}
    		} else {
    			if ( ! current_user_can( 'edit_posts' ) ) {
    				return new WP_Error(
    					'block_cannot_read',
    					__( 'Sorry, you are not allowed to read blocks as this user.' ),
    					array(
    						'status' => rest_authorization_required_code(),
    					)
    				);
    			}
    		}

    		return true;
    	}

    	/**
    	 * Returns block output from block's registered render_callback.
    	 *
    	 * @since 5.0.0
    	 *
    	 * @global WP_Post $post Global post object.
    	 *
    	 * @param WP_REST_Request $request Full details about the request.
    	 * @return WP_REST_Response|WP_Error Response object on success, or WP_Error object on failure.
    	 */
    	public function get_item( $request ) {
    		global $post;

    		$post_id = isset( $request['post_id'] ) ? (int) $request['post_id'] : 0;

    		if ( $post_id > 0 ) {
    			$post = get_post( $post_id );

    			// Set up postdata since this will be needed if post_id was set.
    			setup_postdata( $post );
    		}

    		$registry   = WP_Block_Type_Registry::get_instance();
    		$registered = $registry->get_registered( $request['name'] );

    		if ( null === $registered || ! $registered->is_dynamic() ) {
    			return new WP_Error(
    				'block_invalid',
    				__( 'Invalid block.' ),
    				array(
    					'status' => 404,
    				)
    			);
    		}

    		$attributes = $request->get_param( 'attributes' );

    		// Create an array representation simulating the output of parse_blocks.
    		$block = array(
    			'blockName'    => $request['name'],
    			'attrs'        => $attributes,
    			'innerHTML'    => '',
    			'innerContent' => array(),
    		);

    		// Render using render_block to ensure all relevant filters are used.
    		$data = array(
    			'rendered' => render_block( $block ),
    		);

    		return rest_ensure_response( $data );
    	}

    	/**
    	 * Retrieves block's output schema, conforming to JSON Schema.
    	 *
    	 * @since 5.0.0
    	 *
    	 * @return array Item schema data.
    	 */
    	public function get_item_schema() {
    		if ( $this->schema ) {
    			return $this->schema;
    		}

    		$this->schema = array(
    			'$schema'    => 'http://json-schema.org/schema#',
    			'title'      => 'rendered-block',
    			'type'       => 'object',
    			'properties' => array(
    				'rendered' => array(
    					'description' => __( 'The rendered block.' ),
    					'type'        => 'string',
    					'required'    => true,
    					'context'     => array( 'edit' ),
    				),
    			),
    		);

    		return $this->schema;
    	}
    }
    ```

[View all references](https://developer.wordpress.org/reference/files/wp-includes/rest-api/endpoints/class-wp-rest-block-renderer-controller.php/)
[View on Trac](https://core.trac.wordpress.org/browser/tags/6.9.4/src/wp-includes/rest-api/endpoints/class-wp-rest-block-renderer-controller.php#L17)
[View on GitHub](https://github.com/WordPress/wordpress-develop/blob/6.9.4/src/wp-includes/rest-api/endpoints/class-wp-rest-block-renderer-controller.php#L17-L224)

## 󠀁[Related](https://developer.wordpress.org/reference/classes/wp_rest_block_renderer_controller/?output_format=md#related)󠁿

| Uses | Description | 
| [WP_REST_Controller](https://developer.wordpress.org/reference/classes/wp_rest_controller/)`wp-includes/rest-api/endpoints/class-wp-rest-controller.php` |

Core base controller for managing and interacting with REST API items.

  |

## 󠀁[Changelog](https://developer.wordpress.org/reference/classes/wp_rest_block_renderer_controller/?output_format=md#changelog)󠁿

| Version | Description | 
| [5.0.0](https://developer.wordpress.org/reference/since/5.0.0/) | Introduced. |

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