How to fetch session data in codeigniter? - codeigniter

Question

I am trying to create a login process using codeigniter framework. Form validation is working but there is a problem in session. I can't fetch username after "Welcome-".
controller : Main.php
<?php
class Main extends CI_Controller
{
public function login()
{
$this->load->view('login');
}
public function login_validation()
{
$this->form_validation->set_rules('username','Username','required');
$this->form_validation->set_rules('password','Password','required');
if ($this->form_validation->run())
{
$username = $this->input->post('username');
$password= $this->input->post('password');
//model
$this->load->model('myModel');
if ($this->myModel->can_login($username,$password))
{
$session_data = array('username' => $username);
$this->session->set_userdata('$session_data');
redirect(base_url().'main/enter');
}
else
{
$this->session->set_flashdata('error','Invalid Username Or Password');
redirect(base_url().'main/login');
}
}
else
{
$this->login();
}
}
function enter()
{
if ($this->session->userdata('username')!=' ')
{
echo '<h2> Welcome- '.$this->session->userdata('username').'</h2>';
echo 'Logout';
}
else
{
redirect(base_url().'main/login');
}
}
function logout()
{
$this->session->unset_userdata('username');
redirect(base_url().'main/login');
}
}
?>

Answer 1

Add session library in the constructor
<?php
class Main extends CI_Controller
{
public function __construct()
{
parent::__construct();
// Load form helper library
$this->load->helper('form');
// Load form validation library
$this->load->library('form_validation');
// Load session library
$this->load->library('session');
$username = $this->session->userdata('username');
if (empty($username)) {
redirect('main/logout');
}
}
}
Another method you can load the session library in autoload.php file
File location: application/config/autoload.php
$autoload['libraries'] = array('database', 'email', 'session');

Answer 2

I suggest a slight code rearrangement for enter() that provides a better test for the user name using a tiny bit less code.
function enter()
{
if(empty($this->session->userdata('username')))
{
//base_url() accepts URI segments as a string.
redirect(base_url('main/login'));
}
// The following code will never execute if `redirect()` is called
// because `redirect()` does not return, it calls `exit` instead.
// So, you do not need an `else` block
echo '<h2> Welcome- '.$this->session->userdata('username').'</h2>';
echo 'Logout';
}
empty() will be true for an empty string, NULL, False and a couple of other things. In this case, you are most interested in an empty string or NULL. (empty() documentation HERE.)
You might want to consider adding 'trim' to your validation rules because it strips empty whitespace from the input string. That will remove the possibility of someone trying to input a username using only space characters.
Otherwise, your code should work. If it does not then it's very likely you do not have CodeIgniter sessions configured properly. There are many session setup questions answered here on Stack Overflow that will help you get it running.