Simple Login with CodeIgniter in PHP

Simple Login with CodeIgniter in PHP 

 Create the database

CREATE TABLE `users` (
 `id` tinyint(4) NOT NULL AUTO_INCREMENT,
 `username` varchar(10) NOT NULL,
 `password` varchar(100) NOT NULL,
 PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=1 ;

insert into users (username, password) values ('admin', MD5('password'));

Configure CodeIgniter 

application/config/database.php 

Default Controller

application/config/routes.php 

call landing controller login
$route['default_controller'] = "login";

Default Libraries 

application/config/autoload.php

handle user sessions, and also the URL helper for internal link generation

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

$autoload['helper'] = array('url'); 

Encryption Key

application/config/config.php

$config['encryption_key'] = 'REALLY_LONG_NUMBER';

The Code

User Model (application/models/user.php) 

<?php
Class User extends CI_Model
{
 function login($username, $password)
 {
   $this -> db -> select('id, username, password');
   $this -> db -> from('users');
   $this -> db -> where('username', $username);
   $this -> db -> where('password', MD5($password));
   $this -> db -> limit(1);

   $query = $this -> db -> get();

   if($query -> num_rows() == 1)
   {
     return $query->result();
   }
   else
   {
     return false;
   }
 }
}
?>

Login Controller (application/controllers/login.php)

<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');

class Login extends CI_Controller {

 function __construct()
 {
   parent::__construct();
 }

 function index()
 {
   $this->load->helper(array('form'));
   $this->load->view('login_view');
 }

}

?>

Login View (application/views/login_view.php)

   <h1>Simple Login with CodeIgniter</h1>
   <?php echo validation_errors(); ?>
   <?php echo form_open('verifylogin'); ?>
     <label for="username">Username:</label>
     <input type="text" size="20" id="username" name="username"/>
     <br/>
     <label for="password">Password:</label>
     <input type="password" size="20" id="passowrd" name="password"/>
     <br/>
     <input type="submit" value="Login"/>
   </form>

VerifyLogin Controller (application/controllers/verifylogin.php)

<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');

class VerifyLogin extends CI_Controller {

 function __construct()
 {
   parent::__construct();
   $this->load->model('user','',TRUE);
 }

 function index()
 {
   //This method will have the credentials validation
   $this->load->library('form_validation');

   $this->form_validation->set_rules('username', 'Username', 'trim|required|xss_clean');
   $this->form_validation->set_rules('password', 'Password', 'trim|required|xss_clean|callback_check_database');

   if($this->form_validation->run() == FALSE)
   {
     //Field validation failed.  User redirected to login page
     $this->load->view('login_view');
   }
   else
   {
     //Go to private area
     redirect('home', 'refresh');
   }

 }

 function check_database($password)
 {
   //Field validation succeeded.  Validate against database
   $username = $this->input->post('username');

   //query the database
   $result = $this->user->login($username, $password);

   if($result)
   {
     $sess_array = array();
     foreach($result as $row)
     {
       $sess_array = array(
         'id' => $row->id,
         'username' => $row->username
       );
       $this->session->set_userdata('logged_in', $sess_array);
     }
     return TRUE;
   }
   else
   {
     $this->form_validation->set_message('check_database', 'Invalid username or password');
     return false;
   }
 }
}
?>

Home Controller (application/controllers/home.php)

<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
session_start(); //we need to call PHP's session object to access it through CI
class Home extends CI_Controller {

 function __construct()
 {
   parent::__construct();
 }

 function index()
 {
   if($this->session->userdata('logged_in'))
   {
     $session_data = $this->session->userdata('logged_in');
     $data['username'] = $session_data['username'];
     $this->load->view('home_view', $data);
   }
   else
   {
     //If no session, redirect to login page
     redirect('login', 'refresh');
   }
 }

 function logout()
 {
   $this->session->unset_userdata('logged_in');
   session_destroy();
   redirect('home', 'refresh');
 }

}

?>

Home Page View (application/views/home_view.php)

<html>
 <head>
   <title>Simple Login with CodeIgniter - Private Area</title>
 </head>
 <body>
   <h1>Home</h1>
   <h2>Welcome <?php echo $username; ?>!</h2>
   <a href="home/logout">Logout</a>
 </body>
</html>