WP_REST_Server::embed_links( array $data, bool|string[] $embed = true ): array

775	protected function embed_links( $data, $embed = true ) {776		if ( empty( $data['_links'] ) ) {777			return $data;778		}779 780		$embedded = array();781 782		foreach ( $data['_links'] as $rel => $links ) {783			/*784			 * If a list of relations was specified, and the link relation785			 * is not in the list of allowed relations, don't process the link.786			 */787			if ( is_array( $embed ) && ! in_array( $rel, $embed, true ) ) {788				continue;789			}790 791			$embeds = array();792 793			foreach ( $links as $item ) {794				// Determine if the link is embeddable.795				if ( empty( $item['embeddable'] ) ) {796					// Ensure we keep the same order.797					$embeds[] = array();798					continue;799				}800 801				if ( ! array_key_exists( $item['href'], $this->embed_cache ) ) {802					// Run through our internal routing and serve.803					$request = WP_REST_Request::from_url( $item['href'] );804					if ( ! $request ) {805						$embeds[] = array();806						continue;807					}808 809					// Embedded resources get passed context=embed.810					if ( empty( $request['context'] ) ) {811						$request['context'] = 'embed';812					}813 814					if ( empty( $request['per_page'] ) ) {815						$matched = $this->match_request_to_handler( $request );816						if ( ! is_wp_error( $matched ) && isset( $matched[1]['args']['per_page']['maximum'] ) ) {817							$request['per_page'] = (int) $matched[1]['args']['per_page']['maximum'];818						}819					}820 821					$response = $this->dispatch( $request );822 823					/** This filter is documented in wp-includes/rest-api/class-wp-rest-server.php */824					$response = apply_filters( 'rest_post_dispatch', rest_ensure_response( $response ), $this, $request );825 826					$this->embed_cache[ $item['href'] ] = $this->response_to_data( $response, false );827				}828 829				$embeds[] = $this->embed_cache[ $item['href'] ];830			}831 832			// Determine if any real links were found.833			$has_links = count( array_filter( $embeds ) );834 835			if ( $has_links ) {836				$embedded[ $rel ] = $embeds;837			}838		}839 840		if ( ! empty( $embedded ) ) {841			$data['_embedded'] = $embedded;842		}843 844		return $data;845	}