usky-website/web/application/controllers/admin/adminlogin.php

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

class AdminLogin extends MY_Admin_Controller
{
    protected $check_access = false;

    public function __construct()
    {
        parent::__construct();
        $this->load->model('admin_model' , 'admin');
    }

    public function index()
    {
        $adLogin = $this->input->post('adLogin');
        $adPass  = $this->input->post('adPass');
        $res     = $this->admin->getDetailByLogin($adLogin);
        $return = false;
        if ($res && is_array($res)) {
            if (strtolower($res[0]['adPass']) === md5($adPass)) {
                $_SESSION['adLogin']  =   $res[0]['adLogin'];
                $_SESSION['nickname'] =   $res[0]['nickname'];
                $_SESSION['id']       =   $res[0]['id'];
                $_SESSION['adRole']   =   $res[0]['adRole'];
                $_SESSION['adImg']    =   $res[0]['adImg'];
                $return = true;
            }
        }
        header('Content-Type:json/Application; Charset:utf-8');
        echo json_encode($return);
        exit;
    }

    public function logout()
    {
        session_unset();
        session_destroy();
        redirect(ADMIN_PATH);
    }

}