Consume a REST API in codeigniter controller

I have create a REST API and want to consume my own created API in codeigniter controller.

My created REST APIcontroller(example.php)

   class Example extends REST_Controller {    public function __construct() {     parent::__construct();            $this->load->model('user');   }     public function user_fetch_post() {    //returns all rows if the id parameter doesn't exist,    //otherwise single row will be returned    $id = $this->input->post('id');    $users = $this->user->getRows($id);    //check if the user data exists    if(!empty($users)){        //set the response and exit        $this->response($users, REST_Controller::HTTP_OK);    }else{        //set the response and exit        $this->response(['status' => FALSE,'message' => 'No user were found.'        ], REST_Controller::HTTP_NOT_FOUND);    }    }

model(user.php)

    function getRows($id = ""){    if(!empty($id)){        $query = $this->db->get_where('users', array('id' => $id));        return $query->row_array();    }else{        $query = $this->db->get('users');        return $query->result_array();    }    }

Here i want to call my created api(from example.php)for fetch record in welcome.php controller with basic authentication(uname-admin,pwd-1234)

my controller welcome.php

public function index(){}

Can anybody help to me that how to call my api in controller welcome.php with basic authentication.