How to redirect page and show message when php error on codeigniter?

Question

I want to redirect a page and then show a message when a php error show on codeigniter, how to do that ?

here my php error example

A PHP Error was encountered Severity: Error Message: Call to a member function GetToken() on null Filename: operator_pt/Profil_operatorpt.php Line Number: 95 Backtrace:

Edit : Request from kuldep here my code from controller

public function testkoneksi()
    {

        $this->load->library('form_validation');
  $this->form_validation->set_rules('username','Username','trim|required');
  $this->form_validation->set_rules('password','Password','required');
  $this->form_validation->set_rules('url','URL','required');

        if($this->form_validation->run()===FALSE)
        {
            $this->session->set_flashdata('category_success', 'ISI DATA DENGAN BENAR.');
            redirect('operator_pt/profil_operatorpt', 'refresh');   

        }
        else
        {

        $this->load->helper('url');
        $this->load->library("Nusoap_lib");
        $url = $_POST["url"];
        //$url = 'http://localhost:8082/ws/live.php?wsdl';

        $client = new nusoap_client($url, true);

        $proxy = $client->getproxy();

        //mendapatkan token

        $username = $_POST["username"];
        $password = $_POST["password"];
        $url = $_POST["url"];
        $result=$proxy->GetToken($username, $password);
        $token = $result;
        if (isset($token)) {
    $this->session->set_flashdata('token_sukses', 'KONEKSI DENGAN FEEDER TELAH SUKSES.');
                redirect('operator_pt/profil_operatorpt', 'refresh');   
}
else $this->session->set_flashdata('token_gagal', 'KONEKSI DENGAN FEEDER GAGAL, CEK ULANG USERNAME, PASSWORD & URL-NYA.');
                redirect('operator_pt/profil_operatorpt', 'refresh');       
    }
}

Answer 1

$response = array('status' => true, 'message' => 'Error', 'redirect' => base_url() . 'Path to redirect');
            header('Content-Type:application/json');
            echo json_encode($response);

This may work. Give your error message in place of 'Error'.