WP_REST_Block_Renderer_Controller::get_item() WordPress Method

	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 );
	}