codeigniter hooks can't get $ci object to work - codeigniter

Question

I've just started looking at hooks today not 100% sure what I'm doing wrong but I'm getting an error when I try and use the $ci object in my function.
A PHP Error was encountered
Severity: Notice
Message: Trying to get property of non-object
Filename: hooks/language.php
Line Number: 12
My hooks file looks like this. It's in the hooks directory in my application folder.
class Language{
var $ci;
public function __construct(){
$this->ci =& get_instance();
}
function get_language(){
echo $this->ci->session->userdata('language');
}
}
I need to get the value in the session to use in my function. Am I not supposed to do it like this?
Thanks you!

Answer 1

In the Base4/5.php file the get_instance() function is written and it is conditionally loaded so it won’t be present until after it is loaded. And that's the reason its giving error.

Answer 2

Just done another Google search and it seems the Hook I was using Pre Controller was before the object was created I've changed the hook and it seems to work fine now.

Answer 3

I used post_controller_constructor for my hook, then the CI worked.
And I had to turn on hooks in the config.

Answer 4

Below is default application/config/hooks.php
// Stores the requested URL, which will sometimes be different than previous url
$hook['post_controller'][] = array(
'class' => 'App_hooks',
'function' => 'save_requested',
'filename' => 'App_hooks.php',
'filepath' => 'hooks',
'params' => ''
);
// Allows us to perform good redirects to previous pages.
$hook['post_controller'][] = array(
'class' => 'App_hooks',
'function' => 'prep_redirect',
'filename' => 'App_hooks.php',
'filepath' => 'hooks',
'params' => ''
);
// Maintenance Mode
$hook['post_controller_constructor'][] = array(
'class' => 'App_hooks',
'function' => 'check_site_status',
'filename' => 'App_hooks.php',
'filepath' => 'hooks',
'params' => ''
);
/* End of file hooks.php */
/* Location: ./application/config/hooks.php */
I have changed it to below and it works fine for me
// Stores the requested URL, which will sometimes be different than previous url
$hook['post_controller_constructor'][] = array(
'class' => 'App_hooks',
'function' => 'save_requested',
'filename' => 'App_hooks.php',
'filepath' => 'hooks',
'params' => ''
);
// Allows us to perform good redirects to previous pages.
$hook['post_controller'][] = array(
'class' => 'App_hooks',
'function' => 'prep_redirect',
'filename' => 'App_hooks.php',
'filepath' => 'hooks',
'params' => ''
);
// Maintenance Mode
$hook['post_controller'][] = array(
'class' => 'App_hooks',
'function' => 'check_site_status',
'filename' => 'App_hooks.php',
'filepath' => 'hooks',
'params' => ''
);
/* End of file hooks.php */
/* Location: ./application/config/hooks.php */