PHP - Session Side-effect Error

<?php

$text=(isset($_GET['message']))?$_GET['message']:'';
$formatted_text=nl2br(stripslashes(htmlspecialchars($text)));

echo '<form method="post" action="proceedtopost.php?>'.
'<table>'.
'<td style width="50%"><tr>'.
'<fieldset> Write your post here : <br> <textarea cols="50" rows="12" '.
'id="message" name="message">'.$text.'</textarea>'.
'</fieldset> <p> '.
'<input type="submit" name="submit" formaction="writepost.php" value="Preview" /> '.
'<input type="submit" name="submit" value="Sent" /> '.
'</p>'.
'</td>'.
'<td>'.
'<fieldset> Your post will appear as follows :<br><p> '.
$formatted_text.
'</fieldset>'.
'</td></tr>'.
'</table>'.
'</form>';

<?php

	require('includes/util.inc.php');

	$form = '
		<form action="register.php" method="post">
			<p>username <input type="text" name="username" id="usrinp"></p>
			<p>email <input type="text" name="email" id="emainp"></p>
			<p>password <input type="password" name="password1" id="psw1inp"></p>
			<p>re-enter password <input type="password" name="password2" id="psw2inp"></p>
			<p><img src="captcha.php"/></p>
			<p>captcha <input type="text" name="captcha" id="capinp"></p>
			<p><input type="submit" value="Register" id="subinp"></p>
		</form>
	';

	if(isset($_SESSION['captcha'])) {
		echo $_SESSION['captcha'];
	}

	if ($_SERVER['REQUEST_METHOD'] == 'POST' && !empty($_POST['username']) && !empty($_POST['email'])) {
		if($_POST['captcha'] == $_SESSION['captcha']) {

			$username = $_POST['username'];
			$email = $_POST['email'];
			$password = SHA1($_POST['password1']);
			$password = SHA1($_POST['password2']);

			$q = 'SELECT username FROM users WHERE username = :username';
			$stmt = $pdo->prepare($q);
			$stmt->bindParam(':username', $username);
			$stmt->execute();

				if($stmt->rowCount() > 0) {
					echo "<pre>This username has already been taken</pre>";
				} else {
					$qi = 'INSERT INTO users ( username, password, email ) VALUES ( :username, SHA1(:password), :email )';
				    $query = $pdo->prepare($qi);
				    $result = $query->execute( array( ':username'=>$username, ':password'=>$password, ':email'=>$email ) );

				    if($result) {
				    	header("location:login.php");
						exit;
				    } else {
				      echo '<pre>Error, please try again</pre>';
				    }
				}

		}

	}

	$pageTitle = 'Register';
	include('includes/header.inc.php');
	include('pages/register.html');

?>

<?php

    require('includes/util.inc.php');

    $string = '';
    for ($i = 0; $i < 5; $i++) {
        $string .= chr(rand(97, 122));
    }
    
    $_SESSION['captcha'] = $string;

    $font_path = 'includes/fonts/';

    $captcha_image = imagecreatetruecolor(150, 60);

    $text_color = imagecolorallocate($captcha_image, 0, 0, 0);
    $bg_color = imagecolorallocate($captcha_image, 255, 255, 255);

    imagefilledrectangle($captcha_image, 0, 0, 399, 99, $bg_color);
    imagettftext($captcha_image, 30, 0, 10, 40, $text_color, $font_path . "dashdot.ttf", $_SESSION['captcha']);

    header("Content-type: image/png");
    imagepng($captcha_image);

?>

<?php 

	session_start();

	function class_loader($class) {
		require 'classes/' . $class . '.class' . '.php';
	}

	spl_autoload_register('class_loader');

	$user = (isset($_SESSION['user'])) ? $_SESSION['user'] : null;
	$cat = (isset($_SESSION['cat'])) ? $_SESSION['cat'] : null;

	try {
		$pdo = new PDO('mysql:dbname=phpcat; host=localhost', 'root', '');
	} catch (PDOException $e) {
		$pageTitle = 'Error!';
		include('header.inc.php');
		include('../pages/error.html');
		exit();
	}

I am using the following code in PDO query

$this->query('SELECT * FROM users WHERE id = :id'); // line 11
$this->bind(':id', $_SESSION['users']['id']);       // line 12

it is working on local server, but on live server its giving some error or warning (i am not sure)

PHP Notice:  Undefined index: users in ... on line 12

but the query is still working correctly.

Please guide me what should i do to stop getting this error or warning or notice. Thanks🙂

<?php

if(defined('script') === FALSE){
	exit('Hacking attempt...');
}

if(loginCheck($userInfo) === FALSE){
	redirect('index.php?do=login&returnUrl='.$_SERVER['REQUEST_URI'], FALSE, TRUE);
}

if($configs['giftCardEnabled'] == 'no'){
	alert('This page is currently disabled.', 'index.php?do=home');
}

$action = isset($_GET['action']) ? $_GET['action'] : '';

switch($action){
	
	case 'redeemGiftCard';
	include 'pages/giftCards/redeemGiftCard.php';
	break;
	
	case 'viewGiftCardCodes';
	include 'pages/giftCards/viewGiftCardCodes.php';
	break;
	
	default:
	include 'pages/giftCards/giftCards.php';
	break;

}

?>

<?php
$action = '<input type="button" value="Redeem" onclick="location.href=\'index.php?do=giftCards&action=redeemGiftCard&id='.$row['id'].'&currency='.$row['currency'].'&amount='.$row['amount'].'&csrfKey='.$csrf->csrfKey().'&csrfToken='.$csrf->csrfToken().'\'">';
?>

<?php
$_SESSION['message']['1'] = 'You have successfully redeemed a gift card worth '.$row['currency'].$row['amount'].'';
redirect('index.php?do=testPage1', FALSE, TRUE);// Page, Refresh, Exit //
?>

<?php
$_SESSION['message']['2'] = 'Database error. Please try again later!';
redirect('index.php?do=testPage1', FALSE, TRUE);// Page, Refresh, Exit //
?>

<?php
if(!empty($_SESSION['message']['1'])){
	$success = $_SESSION['message']['1'];
	unset($_SESSION['message']);
}
if(!empty($_SESSION['message']['2'])){
	$error = $_SESSION['message']['2'];
	unset($_SESSION['message']);
}

if(!empty($success)){
	
	print success($success);// HTML and success var //
	
}
if(!empty($error)){
	
	print error($error);// HTML and error var //
	
}
?>

Hi!
I have 2 files based on the Model View Arhitecture.

The file login.php and the config file containing the db connection are in the model folder and the login_view is in view folder.

I am trying to make a login form am display some error messages to the user, but I don't get the error messages.

Can you help me figure it out?

PS: the connection to the db works fine!

Thx!

LOGIN.PHP

<?php
 //start the session
 session_start();
 foreach (glob("model/*.php") as $filename) {
    include $filename;
}

 //form defaults
 $error["alert"]= "";
 $error["user"]= "";
 $error["pass"]= "";
 $input["user"]= "";
 $input["pass"]= "";

if(isset($_POST["submit"]))
{
    //process form
    if($_POST["username"] == "" || $_POST["password"] == ""){
        //display errors
        if($_POST["username"] == ""){$error["user"] = "required";}
        if($_POST["password"] == ""){$error["pass"] = "required";}
        $error["alert"] = "Please fill in the required fields";

        //get the values for the username and password
        $input["user"]= $_POST["username"];
        $input["pass"]= $_POST["password"];
   
        include("../views/login_view.php");
    }
}else{
    include("../views/login_view.php");
}

LOGIN_VIEW.PHP

<?php
    session_start();
    foreach (glob("model/*.php") as $filename) {
        include $filename;
    }
?>
<link href="//maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css">
<script src="//maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<!------ Include the above in your HEAD tag ---------->

<!--author:starttemplate-->
<!--reference site : starttemplate.com-->
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
    <meta name="keywords"
          content="unique login form,leamug login form,boostrap login form,responsive login form,free css html login form,download login form">
    <meta name="author" content="leamug">
    <title>Unique Login Form | Bootstrap Templates</title>
    <link href="/styles/style.css" rel="stylesheet" id="style" type="text/css">
    <!-- Bootstrap core Library -->
    <link href="//netdna.bootstrapcdn.com/bootstrap/3.2.0/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css">
    <script src="//netdna.bootstrapcdn.com/bootstrap/3.2.0/js/bootstrap.min.js"></script>
    <script src="//code.jquery.com/jquery-1.11.1.min.js"></script>
    <!-- Google font -->
    <link href="https://fonts.googleapis.com/css?family=Dancing+Script" rel="stylesheet">
    <!-- Font Awesome-->
    <link href="//maxcdn.bootstrapcdn.com/font-awesome/4.2.0/css/font-awesome.min.css" rel="stylesheet">
</head>
<body>

<!-- Page Content -->
<div class="container">
    <div class="row">
        <div class="col-md-offset-5 col-md-4 text-center">
            <h1 class='text-white'>Login Form</h1>
            <form action ="" method="POST">
              <div class="form-login"></br>
                </br>
                <?php
                    if($error["alert"] != ''){
                        echo "<div class='alert'>".$error["alert"]."</div>";
                    }
                ?>
                <div>
                    <input type="text" name ="username" id="userName" class="form-control input-sm chat-input" placeholder="Username" value= "<?php echo $input['user'] ?>" required/>
                    <?php echo $error['user'] ?>
                </div>
                </br></br>
                <input type="text" name ="password" id="userPassword" class="form-control input-sm chat-input" placeholder="Password" value= "<?php echo $input['password'] ?>" required/>
                <div class="error"> <?php echo  $error['pass'] ?>
                </br></br>
                <div class="wrapper">
                <input type="submit" class="btn btn-primary" value="submit">
                 
                </div>
            </div>
        </div>
    </form>
    </div>
</div>
</body>
</html>