CodeIgniter：尝试调用构造函数方法来检查用户是否已登录（导致无限重定向循环）

Question

I've got a Problem with CodeIgniter 2.1.2 and stuck for hours try to solve it :-/

I know there are plenty(!) of threads about that, but i couldn't find a solution for my problem.

I want to load a method in my constructor to check if a user is logged in, so i tried this:

class my_class extends CI_Controller
{
public function __construct();
parent::__construct();

$this->check(); //doesn't work, endless redirection loop
}

"check()" is:

public function check()
{
    if (! $this->session->userdata('logged_in'))  
    {     
        redirect('/login'); // tried with & without '/'
    }
}

method "login()" looks like this:

public function login()
{
  ...
  //do form validation stuff and on success:
  if ($this->form_validation->run() == TRUE)
    {
     $this->session->set_userdata('logged_in', TRUE);
     redirect('/entry'); 
    }
   //load login_view
}

method "entry()":

public function entry()
{
  //$this->check();//Old (redundant) Version

  //Authorized and Happy...
}

// some other methods, also call the check() method first

So my question is, why the calls in the methods works (but with much redundant calls) and the call in the constructor give me an endless loop? Do I miss something?? (I also didn't change stuff in the htaccess files..)

Thx in advance :-)

Answer 1

To elaborate on what commenters have said:

Ignoring the MY_Controller solution entirely for a moment, the issue is that your __construct() method -- and subsequently, $this->check() -- is being called on every controller, including your login controller.

1. Load homepage. Constructor loads check().
2. Not logged in. Redirect to /login.
3. Login constructor loads check().
4. Not logged in. Redirect to /login.

... and so on and so forth.

The solution is to check what URL is being accessed, and if it belongs to your login controller/method, then don't perform the redirect.

public function check()
{
    if ($this->uri->uri_string() !== 'login' && ! $this->session->userdata('logged_in'))
    {     
        redirect('login');
    }
}

Inversely, your login method should check if the user is indeed already logged in, and if so, redirect him to your homepage or something. But I digress.

---

The MY_Controller solution involves creating a base controller whose constructor performs the logged in check. Then, any controllers where you want to perform that check should extend MY_Controller instead of CI_Controller.

Note that your login controller will not extend MY_Controller, because you don't want to perform the check, or your infinite loop will show up again.