Ticket #38964: 38964.2.diff

src/wp-includes/rest-api/class-wp-rest-server.php

@@ -387 +387 @@
                         // Embed links inside the request.
                         $result = $this->response_to_data( $result, isset( $_GET['_embed'] ) );
 
+                        /**
+                         * Filters the API response.
+                         *
+                         * Allows modification of the response data after inserting
+                         * embedded data (if any) and before echoing the response data.
+                         *
+                         * @since 4.8.1
+                         *
+                         * @param array            $result  Response data to send to the client.
+                         * @param WP_REST_Server   $this    Server instance.
+                         * @param WP_REST_Request  $request Request used to generate the response.
+                         */
+                        $result = apply_filters( 'rest_pre_echo_response', $result, $this, $request );
+
                         $result = wp_json_encode( $result );
 
                         $json_error_message = $this->get_json_last_error();