Duplicate default WP REST API (v2) endpoints - wordpress

Question

How can i duplicate default wp rest api V2 endpoints? I would like to keep default endpoints and routs intact, but would like to use simplified responses for my application.
Wordpress v4.7
My code for now:
function register_custom_routes()
{
$controller = new MY_REST_Posts_Controller;
$controller->register_routes();
}
add_action( 'rest_api_init', 'register_custom_routes', 1 );
class MY_REST_Posts_Controller extends WP_REST_Controller {
// this is a copy of default class WP_REST_Posts_Controller
}
Calling http://localhost/wp/wp-json/ list my namespace ( /myrest ), also
http://localhost/wp/wp-json/myrest/gives me:
{
"namespace": "myrest",
"routes": {
"/myrest": {
"namespace": "myrest",
"methods": [
"GET"
],
...
"/myrest/(?P<id>[\\d]+)": {
"namespace": "myrest",
"methods": [
"GET",
"POST",
"PUT",
"PATCH",
"DELETE"
],
...
}
but when i try to list posts with http://localhost/wp/wp-json/myrest/posts (like with default api route call) it does not work:
{
"code": "rest_no_route",
"message": "No route was found matching the URL and request method",
"data": {
"status": 404
}
}
I need simplified version of get posts response for android app but also want to keep default rest endpoints and routs as is.

Answer 1

Here is the solution. I've wrapped code in wp plugin.
class WP_REST_custom_controller extends WP_REST_Controller {
// this is a copy of default class WP_REST_Posts_Controller
// Edited constructor for cutom namespace and endpoint url
/**
* Constructor.
*
* #since 4.7.0
* #access public
*
* #param string $post_type Post type.
*/
public function __construct() {
$this->post_type = 'post';
$this->namespace = 'custom_namespace/v1';
$obj = get_post_type_object( $post_type );
$this->rest_base = ! empty( $obj->rest_base ) ? $obj->rest_base : $obj->name;
$this->resource_name = 'posts';
$this->meta = new WP_REST_Post_Meta_Fields( $this->post_type );
}
// this is a copy of default class WP_REST_Posts_Controller with necessary edits
}
// Function to register our new routes from the controller.
function register_custom_rest_routes() {
$controller = new WP_REST_custom_controller();
$controller->register_routes();
}
add_action( 'rest_api_init', 'register_custom_rest_routes');