I Search on stackoverflow it show similar question, but its not relative to my query
When i run my project on localhost it not show login page rather it redirect to index page
it show error message in session variable.
Warning: Undefined array key "uid" in
My Codes are given below :
index.php
<?php
session_start();
if(strlen($_SESSION['uid'])=="" )
{
header('location:logout.php');
} else {
?>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>Marriage Certificate System</title>
<!-- Google Font: Source Sans Pro -->
<link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Source+Sans+Pro:300,400,400i,700&display=fallback">
<!-- Font Awesome -->
<link rel="stylesheet" href="plugins/fontawesome-free/css/all.min.css">
<link rel="stylesheet" href="plugins/fontawesome-free/css/fontawesome.css">
<!-- Ionicons -->
<link rel="stylesheet" href="https://code.ionicframework.com/ionicons/2.0.1/css/ionicons.min.css">
<!-- Tempusdominus Bootstrap 4 -->
<link rel="stylesheet" href="plugins/tempusdominus-bootstrap-4/css/tempusdominus-bootstrap-4.min.css">
<!-- iCheck -->
<link rel="stylesheet" href="plugins/icheck-bootstrap/icheck-bootstrap.min.css">
<!-- JQVMap -->
<link rel="stylesheet" href="plugins/jqvmap/jqvmap.min.css">
<!-- Theme style -->
<link rel="stylesheet" href="dist/css/adminlte.min.css">
<!-- overlayScrollbars -->
<link rel="stylesheet" href="plugins/overlayScrollbars/css/OverlayScrollbars.min.css">
<!-- Daterange picker -->
<link rel="stylesheet" href="plugins/daterangepicker/daterangepicker.css">
<!-- summernote -->
<link rel="stylesheet" href="plugins/summernote/summernote-bs4.min.css">
</head>
<body class="hold-transition sidebar-mini layout-fixed">
<div class="wrapper">
<!-- Preloader -->
<div class="preloader flex-column justify-content-center align-items-center">
<img class="animation__shake" src="#" alt="AdminLTELogo" height="90" width="90">
</div>
<!-- Navbar -->
<nav class="main-header navbar navbar-expand navbar-white navbar-light">
<!-- Left navbar links -->
<ul class="navbar-nav">
<li class="nav-item">
<a class="nav-link" data-widget="pushmenu" href="#" role="button"><i class="fas fa-bars"></i></a>
</li>
<!-- <li class="nav-item d-none d-sm-inline-block">
<a href="index3.html" class="nav-link">Home</a>
</li>
<li class="nav-item d-none d-sm-inline-block">
<a href="#" class="nav-link">Contact</a>
</li> -->
</ul>
<!-- Right navbar links -->
<ul class="navbar-nav ml-auto">
<!-- Notifications Dropdown Menu -->
<li class="nav-item dropdown">
<a class="nav-link" data-toggle="dropdown" href="#">
<i class="far fa-bell"></i>
<span class="badge badge-warning navbar-badge">15</span>
</a>
<div class="dropdown-menu dropdown-menu-lg dropdown-menu-right">
<span class="dropdown-item dropdown-header">15 Notifications</span>
<div class="dropdown-divider"></div>
<a href="#" class="dropdown-item">
<i class="fas fa-envelope mr-2"></i> 4 new messages
<span class="float-right text-muted text-sm">3 mins</span>
</a>
<div class="dropdown-divider"></div>
<a href="#" class="dropdown-item">
<i class="fas fa-users mr-2"></i> 8 friend requests
<span class="float-right text-muted text-sm">12 hours</span>
</a>
<div class="dropdown-divider"></div>
<a href="#" class="dropdown-item">
<i class="fas fa-file mr-2"></i> 3 new reports
<span class="float-right text-muted text-sm">2 days</span>
</a>
<div class="dropdown-divider"></div>
<a href="#" class="dropdown-item dropdown-footer">See All Notifications</a>
</div>
</li>
<li class="nav-item">
<a class="nav-link" data-widget="fullscreen" href="#" role="button">
<i class="fas fa-expand-arrows-alt"></i>
</a>
</li>
<li class="nav-item">
<a class="nav-link" data-widget="fullscreen" href="logout.php" role="button">
<i class="fas fa-solid fa-user"></i>
</a>
</li>
</ul>
</nav>
<!-- /.navbar -->
<!-- Main Sidebar Container -->
<aside class="main-sidebar sidebar-dark-primary elevation-4">
<!-- Brand Logo -->
<a href="index3.html" class="brand-link">
<img src="#" alt="AdminLTE Logo" class="brand-image img-circle elevation-3" style="opacity: .8">
<span class="brand-text font-weight-light">GSS Qadian</span>
</a>
<!-- Sidebar -->
<div class="sidebar">
<!-- Sidebar user panel (optional) -->
<div class="user-panel mt-3 pb-3 mb-3 d-flex">
<div class="image">
<img src="img/avatar.png" class="img-circle elevation-2" alt="User Image" >
</div>
<div class="info">
<a href="#" class="d-block">Welcome <?php echo $_SESSION['name'];?></a>
</div>
</div>
<!-- SidebarSearch Form -->
<!-- <div class="form-inline">
<div class="input-group" data-widget="sidebar-search">
<input class="form-control form-control-sidebar" type="search" placeholder="Search" aria-label="Search">
<div class="input-group-append">
<button class="btn btn-sidebar">
<i class="fas fa-search fa-fw"></i>
</button>
</div>
</div>
</div> -->
<!-- Sidebar Menu -->
<nav class="mt-2">
<ul class="nav nav-pills nav-sidebar flex-column" data-widget="treeview" role="menu" data-accordion="false">
<!-- Add icons to the links using the .nav-icon class
with font-awesome or any other icon font library -->
<li class="nav-item menu-open">
<a href="#" class="nav-link active">
<!-- <i class="nav-icon fas fa-tachometer-alt"></i> -->
<p>
Dashboard
<i class="right fas fa-angle-left"></i>
</p>
</a>
<ul class="nav nav-treeview">
<li class="nav-item">
<a href="./sadd.php" class="nav-link">
<i class="fas fa-light fa-file-pen"></i>
<p> Add new </p>
</a>
</li>
<li class="nav-item">
<a href="./sdisplay.php" class="nav-link">
<i class="fas fa-light fa-pen-to-square"></i>
<p>Edit</p>
</a>
</li>
<li class="nav-item">
<a href="./sdisplay.php" class="nav-link">
<i class="fas fa-light fa-trash-can"></i>
<p>Delete</p>
</a>
</li>
<li class="nav-item">
<!-- <a href="cdisplay.php" class="nav-link active"> -->
<a href="cdisplay.php" class="nav-link">
<i class=" fa-light fa-display"></i>
<p>Display All Records</p>
</a>
</li>
</ul>
</li>
<!-- <li class="nav-header">MISCELLANEOUS</li> -->
<!-- <li class="nav-item">
<a href="iframe.html" class="nav-link">
<i class="nav-icon fas fa-ellipsis-h"></i>
<p>Tabbed IFrame Plugin</p>
</a>
</li> -->
</ul>
</nav>
<!-- /.sidebar-menu -->
</div>
<!-- /.sidebar -->
</aside>
<!-- Content Wrapper. Contains page content -->
<div class="content-wrapper">
<!-- Content Header (Page header) -->
<div class="content-header">
<div class="container-fluid">
<div class="row mb-2">
<div class="col-sm-6">
<h1 class="m-0">Dashboard</h1>
</div><!-- /.col -->
<div class="col-sm-6">
<ol class="breadcrumb float-sm-right">
<li class="breadcrumb-item"><a href="#">Home</a></li>
<li class="breadcrumb-item active">..</li>
</ol>
</div><!-- /.col -->
</div><!-- /.row -->
</div><!-- /.container-fluid -->
</div>
<!-- /.content-header -->
<!-- Main content -->
<section class="content">
<div class="container-fluid">
<!-- Small boxes (Stat box) -->
<!-- /.row -->
<!-- Main row -->
<div class="row">
</div>
<!-- /.row (main row) -->
</div><!-- /.container-fluid -->
</section>
<!-- /.content -->
</div>
<!-- /.content-wrapper -->
<footer class="main-footer">
<!-- <div class="float-right d-none d-sm-inline-block">
<b>Version</b> 3.2.0
</div> -->
</footer>
<!-- Control Sidebar -->
<aside class="control-sidebar control-sidebar-dark">
<!-- Control sidebar content goes here -->
</aside>
<!-- /.control-sidebar -->
</div>
<!-- ./wrapper -->
<!-- jQuery -->
<script src="plugins/jquery/jquery.min.js"></script>
<!-- jQuery UI 1.11.4 -->
<script src="plugins/jquery-ui/jquery-ui.min.js"></script>
<!-- Resolve conflict in jQuery UI tooltip with Bootstrap tooltip -->
<!-- <script>
$.widget.bridge('uibutton', $.ui.button)
</script> -->
<!-- Bootstrap 4 -->
<script src="plugins/bootstrap/js/bootstrap.bundle.min.js"></script>
<!-- ChartJS -->
<script src="plugins/chart.js/Chart.min.js"></script>
<!-- Sparkline -->
<script src="plugins/sparklines/sparkline.js"></script>
<!-- JQVMap -->
<script src="plugins/jqvmap/jquery.vmap.min.js"></script>
<script src="plugins/jqvmap/maps/jquery.vmap.usa.js"></script>
<!-- jQuery Knob Chart -->
<script src="plugins/jquery-knob/jquery.knob.min.js"></script>
<!-- daterangepicker -->
<script src="plugins/moment/moment.min.js"></script>
<script src="plugins/daterangepicker/daterangepicker.js"></script>
<!-- Tempusdominus Bootstrap 4 -->
<script src="plugins/tempusdominus-bootstrap-4/js/tempusdominus-bootstrap-4.min.js"></script>
<!-- Summernote -->
<script src="plugins/summernote/summernote-bs4.min.js"></script>
<!-- overlayScrollbars -->
<script src="plugins/overlayScrollbars/js/jquery.overlayScrollbars.min.js"></script>
<!-- AdminLTE App -->
<script src="dist/js/adminlte.js"></script>
<!-- AdminLTE for demo purposes -->
<!-- <script src="dist/js/demo.js"></script> -->
<!-- AdminLTE dashboard demo (This is only for demo purposes) -->
<script src="dist/js/pages/dashboard.js"></script>
</body>
</html>
<?php } ?>signin.php
<?php
session_start();
// include Function file
include_once('function.php');
// Object creation
$usercredentials=new DB_con();
if(isset($_POST['submit']))
{
// Posted Values
$uname=$_POST['username'];
$pasword=md5($_POST['password']);
//Function Calling
$ret=$usercredentials->signin($username,$pasword);
$num=mysqli_fetch_array($ret);
if($num>0)
{
$_SESSION['uid']=$num['id'];
$_SESSION['fname']=$num['name'];
// For success
echo "<script>window.location.href='index.php'</script>";
}
else
{
// Message for unsuccessfull login
echo "<script>alert('Invalid details. Please try again');</script>";
echo "<script>window.location.href='signin.php'</script>";
}
}
?>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>Marriage Certificate</title>
<!-- Google Font: Source Sans Pro -->
<link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Source+Sans+Pro:300,400,400i,700&display=fallback">
<!-- Font Awesome -->
<link rel="stylesheet" href="plugins/fontawesome-free/css/all.min.css">
<!-- icheck bootstrap -->
<link rel="stylesheet" href="plugins/icheck-bootstrap/icheck-bootstrap.min.css">
<!-- Theme style -->
<link rel="stylesheet" href="dist/css/adminlte.min.css">
</head>
<body class="hold-transition login-page">
<div class="login-box">
<div class="register-logo">
<a href="../../index2.html"><b>Marriage </b> Certificate</a>
</div>
<!-- /.login-logo -->
<div class="card">
<div class="card-body login-card-body">
<p class="login-box-msg">Sign in</p>
<form action="" method="post">
<div class="input-group mb-3">
<input type="text" class="form-control" placeholder="Username" name="uname">
<div class="input-group-append">
<div class="input-group-text">
<span class="fas fa-envelope"></span>
</div>
</div>
</div>
<div class="input-group mb-3">
<input type="password" class="form-control" placeholder="Password" name="password">
<div class="input-group-append">
<div class="input-group-text">
<span class="fas fa-lock"></span>
</div>
</div>
</div>
<div class="row">
<div class="col-8">
<!-- <div class="icheck-primary">
<input type="checkbox" id="remember">
<label for="remember">
Remember Me
</label>
</div> -->
</div>
<!-- /.col -->
<div class="col-4">
<input type="submit" name="submit" class="btn btn-primary btn-block" value="Signin">
</div>
<!-- /.col -->
</div>
</form>
<!-- <div class="social-auth-links text-center mb-3">
<p>- OR -</p>
<a href="#" class="btn btn-block btn-primary">
<i class="fab fa-facebook mr-2"></i> Sign in using Facebook
</a>
<a href="#" class="btn btn-block btn-danger">
<i class="fab fa-google-plus mr-2"></i> Sign in using Google+
</a>
</div> -->
<!-- /.social-auth-links -->
<!-- <p class="mb-1">
<a href="forgot-password.html">I forgot my password</a>
</p> -->
<p class="mb-0">
<a href="register.php" class="text-center">Register a new membership</a>
</p>
</div>
<!-- /.login-card-body -->
</div>
</div>
<!-- /.login-box -->
<!-- jQuery -->
<script src="../../plugins/jquery/jquery.min.js"></script>
<!-- Bootstrap 4 -->
<script src="../../plugins/bootstrap/js/bootstrap.bundle.min.js"></script>
<!-- AdminLTE App -->
<script src="../../dist/js/adminlte.min.js"></script>
</body>
</html>Please Check my Codes and direction me to solve issue. I appriciate your help
>Solution :
It happens because your index.php is the first file that load and when it loads the session variable is empty, your $_SESSION variable does not has the uid index, you can fix the warning if you use the functions isset and empty, example:
<?php
session_start();
if(!isset($_SESSION['uid']) || empty($_SESSION['uid'])) {
header('location:logout.php');
} else {