$user_id = 1;
$this->load->helper('url');
$this->load->library('rest_client', array(
'server' => site_url('api/example/'),
//'http_user' => 'admin',
//'http_pass' => '1234',
//'http_auth' => 'basic' // or 'digest'
));
$result = $this->rest_client->get('users/id/'.$user_id.'/format/json');
object(stdClass)#31 (2) {
["status"]=>
bool(false)
["error"]=>
string(16) "Invalid API key "
}