Codeigniter-PHP会话有问题

Question

I was surfing the net and found official page :

With Adding Custom Session Data paragraph

https://www.codeigniter.com/user_guide/libraries/sessions.html

I tried implement the code to mine but it still doesnt work:

public function login_validation(){
        $data = new stdClass();
        $this->load->database(); // load database
        $this->load->library('form_validation');
        $this->load->helper('url');
        $this->load->library('session');

        $this->form_validation->set_rules('email', 'email', 'required|trim|callback_validate_credentials');
        $this->form_validation->set_rules('password', 'password', 'required|trim', array(
            'required'      => 'Password field is empty'));

        $this->load->model("model_users");
        $email = $this->input->post('email');
        $user_id = $this->model_users->get_user_id($email);
        $user    = $this->model_users->get_user($user_id);

        if ($this->form_validation->run()){
            $newdata = array(
                   'username'  => 'johndoe',
                   'email'     => 'johndoe@some-site.com',
                   'logged_in' => TRUE
               );
            // $_SESSION['user_id']      = (bool)true;
            // $_SESSION['email']      = $this->input->post('email');
            // $_SESSION['logged_in']    = (bool)true;
            // $_SESSION['username']     = (string)$user->priv;
        $this->session->set_userdata($newdata);
        $this->members();
        } else{
            $this->login();
        }
    }

Im getting this error in this line - <?php echo $_SESSION['username']; ?> <?php echo $_SESSION['username']; ?> :

A PHP Error was encountered

Severity: Notice

Message: Undefined index: username

Filename: views/catalog.php

Line Number: 19

Backtrace:

I dont see any mistake and Im really anxious right now , because nothing is working. Sorry for bad formulation of question. If you need extra code lines just say I will paste it in pastebin.com

Answer 1

Setting new session

$newdata = array(
   'username'  => 'johndoe',
   'email'     => 'johndoe@some-site.com',
   'logged_in' => TRUE
);

$this->session->set_userdata($newdata); # setting session data

Retrieving the session

$username = $this->session->userdata('username');

echo $username;

In view

echo $this->session->userdata('username');

---

Note:

If you want to passing the session data to view you can bind it with $data[] or in view can call it directly .

Answer 2

Since PHP native session are not implemented in CI:2 so you can't use $_SESSION in codeigniter 2 rather you can use

$this->session->set_userdata('key','data');
//to fetch this session you can do
$this->session->userdata('key');

But due to some reason you need to implement PHP native session you can add this as a library Check library here