Codeigniter constructor - check if user is logged in

Question

I am attempting to create a constructor for my controller that references a function that I have contained in a helper which is autoloaded.

The function checks whether or not the user is logged in, if so it redirects them to the login page.

It appears that I have not setup the construct correctly as I am receiving the following error:

Fatal error: Call to undefined method Profile::is_logged_in()

This is the controller:

<?php

if (!defined('BASEPATH'))
    exit('No direct script access allowed');

class Profile extends CI_Controller {

       public function __construct()
       {
            parent::__construct();
            //function inside autoloaded helper, check if user is logged in, if not redirects to login page
            $this->is_logged_in();
       }

    public function index() {

    echo 'hello';

    }

} 

I only want to make function within the controller accessible if the user is logged in.

This is the helper which is autoloaded

$autoload['helper'] = array('url','array','html','breadcrumb','form','function','accesscontrol');

(accesscontrol_helper.php):

<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');

    function is_logged_in()
    {
        $is_logged_in = $this->session->userdata('is_logged_in');
        if(!isset($is_logged_in) || $is_logged_in != true)
        {
            echo 'You don\'t have permission to access this page. <a href="../login">Login</a>';    
            die();      
            //$this->load->view('login_form');
        }       
    }

Why would I not be able to run the function? Is containing the code in the helper the best method?

Answer 1

As other already mentioned, helpers are simply a collection of functions. Expanding on them:

• since they're loaded more than once sometimes, you need to specify not to declare a function if already present, all you'll raise an error.

• You cannot, moreover, call a CI's class inside them without first instantiating the main CI object. This is a more proper way to use your helper function:

  if(!function_exists('is_logged_in'))    
  {
      function is_logged_in()
      {
      $CI =& get_instance();
      $is_logged_in = $CI->session->userdata('is_logged_in');
         if(!isset($is_logged_in) || $is_logged_in != true)
         {
          echo 'You don\'t have permission to access this page. <a href="../login">Login</a>';    
          die();      
         }       
      }
  }
  

I would also have it return instead of echo, and move the die() to the controller, but this is another story.

Answer 2

Helpers are just included functions, so you don't need to access it with $this. Just call it as a normal function:

is_logged_in();