How to handle Session in Codeigniter

Handle session is very important when creating a member-based website where the user needs to register and login to their account to access website content.

With the help of a session, it is easier to identify the user and display the content accordingly.

In Codeigniter, require the loading session library to start work with Session. There are inbuilt methods are available that makes easier to handle session operations.

Load Library
Set
Get
Destroy
Flash Data
Conclusion

1. Load Library

There are two ways to load the library –

Using autoload
Loading on the controller

Using autoload

Open application/config/autoload.php and add the session in libraries array().

$autoload['libraries'] = array("session");

Loading on the controller

Created a application/controllers/user.php file where defined a constructor function and load the session library using $this->load->library() method.

<?php
defined('BASEPATH') OR exit('No direct script access allowed');
class User extends CI_Controller {

    public function __construct() { 

         // Load session library 
         $this->load->library('session');
    }
}

2. Set

To create session variable use $this->session->set_userdata(). With this, you can either define one or multiple variables at a time.

Single variable

$this->session->set_userdata("username","yssyogesh");

Multiple variable

$data = array(
   "username" => "yssyogesh",
   "email" => "yogesh@makitweb.com",
   "user_id" => 2
);

$this->session->set_userdata($data);

3. Get

Specific variable

With userdata() method you can read a session variable by passing its name e.g. username.

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

All variable

To get all variable data don’t pass any value in the userdata() method.

$this->session->userdata();

4. Destroy

Destroy single variable

Pass the name of the session variable in unset_userdata() method to remove.

$this->session->unset_userdata('username');

Destroy all variable

The sess_destroy() method clear all session variable.

$this->session->sess_destroy();

5. Flash data

Flashdata is a type of session data that will only available for the next request and automatically destroyed after that.

Create

To create flashdata use $this->session->set_flashdata() method.

$this->session->set_flashdata('msg','Record updated successfully.');

Retrieve

Read the variable value using flashdata() method. The userdata() method does not work with flashdata to get the value.

$this->session->flashdata('msg');

6. Conclusion

It’s better to use autoload to load the session library because you don’t have the need to again load every time on each controller.

With flashdata you can temporarily create a variable that will only available for next request then it automatically gets destroyed.

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How to Handle Session in Codeigniter

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