Tutorial ke # 3 : Pemrograman Web : Membuat CRUD Data Mahasiswa (Halaman Login)

Halaman Login. Nama File : index.php

Jika login Gagal :

Sourcecode :

<?php
//cek jika session masih ada, arahkan ke halaman admin
session_start();
if(isset($_SESSION['user_sesion'])){
  header('location: data_mahasiswa.php');
}
?>
<title>Login Page</title>
<link rel="stylesheet" type="text/css" href="bootstrap3/css/bootstrap.css">
<link rel="stylesheet" type="text/css" href="bootstrap3/css/bootstrap-theme.css">
<div class="container">
  <h3>LOGIN ADMIN</h3>
  <?php if(isset($_GET['error']) == 'yes'){ ?>
    <div class="alert alert-danger">Username / password Salah !</div>
  <?php } ?>
    <form action="login_cek.php" method="POST" class="col-md-4">
      <p>Username :
        <input type="text" name="username" placeholder="ketikkan username" class="form-control">
      </p>
      <p>Password :
        <input type="password" name="password" placeholder="ketikkan password" class="form-control">
      </p>
      <p>
        <button type="submit" class="btn btn-primary">LOGIN</button>
        <button type="reset" class="btn btn-default">RESET</button>
      </p>
    </form>
</div>

File : login_cek.php

<?php
include 'config/koneksi.php';
$username = mysqli_real_escape_string($koneksi, $_POST['username']);
$password = mysqli_real_escape_string($koneksi, $_POST['password']);
$password = md5($password);
$sql = "SELECT * FROM users WHERE user_name = '$username' AND user_password = '$password'";

$query = mysqli_query($koneksi, $sql);
if (!$query) {
  die("Query Gagal : ".mysqli_error($koneksi));
}
else {
  $row = mysqli_fetch_array($query);
}

$user_db = $row['user_name'];
$pass_db = $row['user_password'];

if ($user_db == $username AND $pass_db == $password) {
  //jika berhasil Daftarkan Session dan arahkan ke halaman admin
  session_start();
  $_SESSION['user_sesion'] = $user_db;
  header('location: data_mahasiswa.php');
}else{
  //jika gagal
  header('location: index.php?error=yes');
}
?>