Simple Login using CodeIgniter & Database

Ok now I will explain about to create simple login using CodeIgniter (Update using codeigniter version 3.0) & Database (Example I use MySQL). And in this case, I think you’ve installed CodeIgniter on your local PC or localhost. Next, just follow this intructions:

1. Create Database.

   CREATE TABLE `users` (
     `id_user` int(11) NOT NULL AUTO_INCREMENT,
     `username` varchar(50) NOT NULL,
     `password` varchar(50) NOT NULL,
     PRIMARY KEY (`id_user`)
   ) ENGINE=InnoDB DEFAULT CHARSET=latin1;
   

   Note:
   Oh ya remember to add one row or data to table admin, example with name “Imron” and password “password” with md5.
   

   INSERT INTO users(username, password) VALUES('Imron',md5('password'));
   

   And for certainty, use the select query to see the data that we have just entered.

   SELECT * FROM users;
    id_user | username |             password             
   ---------+----------+----------------------------------
          1 | Imron    | 5f4dcc3b5aa765d61d8327deb882cf99
   (1 row)
   

2. Configure database on CodeIgniter.
   Update the file yourcodeigniter/application/config/database.php in your CodeIgniter installation with your database info:

   $active_group = 'default';
   $query_builder = TRUE;
   
   $db['default'] = array(
   	'dsn'	=> '',
   	'hostname' => 'localhost',
   	'username' => 'yourusername',
   	'password' => 'yourpassword',
   	'database' => 'yourdatabase',
   	'dbdriver' => 'mysqli',
   	'dbprefix' => '',
   	'pconnect' => FALSE,
   	'db_debug' => TRUE,
   	'cache_on' => FALSE,
   	'cachedir' => '',
   	'char_set' => 'utf8',
   	'dbcollat' => 'utf8_general_ci',
   	'swap_pre' => '',
   	'encrypt' => FALSE,
   	'compress' => FALSE,
   	'stricton' => FALSE,
   	'failover' => array(),
   	'save_queries' => TRUE
   );
   

3. Set Encryption Key config CodeIgniter
   We need set Encryption Key to enable session libraries. Open yourcodeigniter/application/config/config.php

   /*
   |--------------------------------------------------------------------------
   | Encryption Key
   |--------------------------------------------------------------------------
   |
   | If you use the Encryption class, you must set an encryption key.
   | See the user guide for more info.
   |
   | http://codeigniter.com/user_guide/libraries/encryption.html
   |
   */
   $config['encryption_key'] = 'learn_ci';
   

4. Then now open yourcodeigniter/application/config/autoload.php and change the code like this:

   $autoload['libraries'] = array('session');
   
   
   /*
   | -------------------------------------------------------------------
   |  Auto-load Drivers
   | -------------------------------------------------------------------
   | These classes are located in the system/libraries folder or in your
   | application/libraries folder within their own subdirectory. They
   | offer multiple interchangeable driver options.
   |
   | Prototype:
   |
   |	$autoload['drivers'] = array('cache');
   */
   
   $autoload['drivers'] = array();
   
   
   /*
   | -------------------------------------------------------------------
   |  Auto-load Helper Files
   | -------------------------------------------------------------------
   | Prototype:
   |
   |	$autoload['helper'] = array('url', 'file');
   */
   
   $autoload['helper'] = array('url');
   

   Explanations:
   This function is used to automatically load helper and library (like url and session) if we run codeigniter. So if we load helper and library in this file, we don’t need to load helper or library manually in all controller like this code:

   $this->load->helper('url')
   or
   $this->load->library('session')
   

   So if we write in this autoload.php, we write enough just once for all controllers.

5. Code
   Create yourcodeigniter/application/models/Login_model.php:

   <?php
   defined('BASEPATH') OR exit('No direct script access allowed');
   
   /**
    * @name: Login model
    * @author: Imron Rosdiana
    */
   class Login_model extends CI_Model
   {
   
       function __construct() {
           parent::__construct();
           $this->load->database();
       }
   
       public function validate_user($data) {
           $this->db->where('username', $data['username']);
           $this->db->where('password', md5($data['password']));
           return $this->db->get('users')->row();
       }
   
       function __destruct() {
           $this->db->close();
       }
   }
   

   Explanations:

   • Line 13 is using to load database, so with this function we can connect to database with the config is from database.php (above file)
   • Line 17-19 is Query builder from ci, if we translate the code, may be like this:

     SELECT * FROM users WHERE username = "$data['username']" AND password = "$data['password']"
     

     For more info you can read from this http://www.codeigniter.com/user_guide

   • Line 23 is the destructor. This is PHP OOP feature, for more info read this http://php.net/manual/en/language.oop5.decon.php

   Then create yourcodeigniter/application/controllers/Login.php:

   <?php
   defined('BASEPATH') OR exit('No direct script access allowed');
   
   /**
    * @name Login.php
    * @author Imron rosdiana
    */
   class Login extends CI_Controller
   {
   
       function __construct() {
           parent::__construct();
           $this->load->model("login_model", "login");
           if(!empty($_SESSION['id_user']))
               redirect('home');
       }
   
       public function index() {
           if($_POST) {
               $result = $this->login->validate_user($_POST);
               if(!empty($result)) {
                   $data = [
                       'id_user' => $result->id_user,
                       'username' => $result->username
                   ];
   
                   $this->session->set_userdata($data);
                   redirect('home');
               } else {
                   $this->session->set_flashdata('flash_data', 'Username or password is wrong!');
                   redirect('login');
               }
           }
   
           $this->load->view("login");
       }
   }
   

   Explanations:

   • Line 13, this function is used to load model. In this project we create Login_model.php, so this function is to load it and we using alias. So with the alias we can call the model with this $this->login->namefunction, and if we not using alias we can call the model with $this->login_model->namefunction
   • Line 14-15 is using to validate session, so if we have logged in before, then we don’t need login again and the page is redirect to Home controller
   • Line 19 is using if we get the post from login page
   • Line 20 is to load model, and get the save the result to $result variable
   • Line 21-28 is used to check if $result not empty or the user already exist on database, we create the session and go to home page
   • Line 29-32 is used if user not in database, so login is failed and back again to login page
   • Line 35 is to load form login

   Then create yourcodeigniter/application/controllers/Home.php

   <?php
   defined('BASEPATH') OR exit('No direct script access allowed');
   
   /**
    * @name Home.php
    * @author Imron Rosdiana
    */
   class Home extends CI_Controller
   {
   
       function __construct() {
           parent::__construct();
   
           if(empty($this->session->userdata('id_user'))) {
               $this->session->set_flashdata('flash_data', 'You don\'t have access!');
               redirect('login');
           }
       }
   
       public function index() {
           $this->load->view('home');
       }
   
       public function logout() {
           $data = ['id_user', 'username'];
           $this->session->unset_userdata($data);
   
           redirect('login');
       }
   }
   

   Explanations:

   • Line 14-17 is used if the user accesses the home page before login, so the user will be redirect to login page
   • Line 20-22 is to load home page if user already login
   • Line 24-28 is used if user logout from home page, so we must remove the session

   The last is create home page on yourcodeigniter/application/views/home.php:

   <!DOCTYPE html>
   <html>
       <head>
           <title>Learn CI</title>
       </head>
       <body>
           <h1>Welcome <?= $this->session->userdata('username') ?></h1>
           <a href="<?= site_url('home/logout') ?>">Logout</a>
       </body>
   </html>
   

   And create login page on yourcodeigniter/application/view/login.php:

   <!DOCTYPE html>
   <html lang="en">
   <head>
       <meta charset="UTF-8">
       <title>Learning CI</title>
   </head>
   <body>
       <?php if(isset($_SESSION)) {
           echo $this->session->flashdata('flash_data');
       } ?>
   
       <form action="<?= site_url('login') ?>" method="post">
           <label for="username">Username</label>
           <input type="text" name="username" />
           <label for="password"></label>
           <input type="text" name="password" />
           <button type="submit">Login</button>
       </form>
   </body>
   </html>
   

Very easy if you understand this. 😀
Full Code, download in here https://www.mediafire.com/?luzehcvj301dbwv