stay in dashboard when the user is logged - php

Question

how can I stay in dashboard when the user is logged even though when the user write localhost/storeLTE/login/ then stay home. but my code doesnt work.
public function getAccess(){
if ($this->session->set_userdata('username')) {
redirect('home');
}
$username = $this->security->xss_clean($this->input->post('username'));
$password = $this->security->xss_clean($this->input->post('password'));
$array = $this->User_model->login($username,$password);
if($array[0] == 0){
echo 0;
}else{
$data_session = array(
'id' => $array[0]['iduser'],
'username' => $array[0]['username'],
'password' => $array[0]['password'],
'name' => $array[0]['name'],
'last_name' => $array[0]['last_name'],
'type' => $array[0]['idType'],
'logged_in' => TRUE
);
$this->session->set_userdata('log',$data_session);
}
}

Answer 1

if ($this->session->set_userdata('username')) {
should be
if ($this->session->userdata('username')) {
or
if ($this->session->userdata('username') !== NULL) {
//since NULL is returned if item is not found
Docs.

Answer 2

FYI
Its is NOT a good sign of STORING PASSWORD IN THE SESSION. Its better to store name, type, logged_in, id.
In Controller
function getAccess(){
$this->load->library('session'); # load library here or in autoload.php
if($this->session->userdata('logged_in') == TRUE)
{
redirect('home');
}
else
{
$username = $this->security->xss_clean($this->input->post('username'));
$password = $this->security->xss_clean($this->input->post('password'));
$result = $this->User_model->login($username,$password);
if($result == FALSE)
{
echo 'Invalid Login';
}
else{
$data_session = array(
'id' => $result[0]['iduser'],
'username' => $result[0]['username'], # Better to remove
'password' => $result[0]['password'], # Better to remove
'name' => $result[0]['name'],
'last_name' => $result[0]['last_name'],
'type' => $result[0]['idType'],
'logged_in' => TRUE
);
$this->session->set_userdata('log',$data_session);
$this->load->view('home'); # Load the view
}
}
}
In Model
function login($username,$password)
{
$query = $this->db->query("SELECT * FROM table name WHERE username = '$username' AND password = '$password'");
$result = $query->result_array();
if (count($result) > 1 || empty($result))
{
return FALSE;
}
else {
return $result;
}
}

Answer 3

if ($this->session->set_userdata('username')) {
redirect('home');
}
change this to
if ($this->session->userdata('username') !='') {
redirect('home');
}