我正在使用PHP开发一个登录页面，目的是将用户带到登录页面。有一个数据库，里面填充了所有的表单字段，我设置了测试代码来验证字段是否被正确提取。但当登录网站本身被使用时，无论字段中填充了什么，它都会重定向到自己，并将字段清除。我已经尝试了几种不同的方法来调用页面，但仍然无法让它做任何事情，只能清除字段并重定向到干净的版本。这是相关的代码
<?php
session_start();
include 'config.php';
if(isset($_SESSION['user'])!="" && isset($_SESSION['store'])!=""){
header('Location: http://server-ip/landing.php');
exit();
}
$error = false;
if($_SERVER["REQUEST_METHOD"] == "POST" && ($_POST['btn-login'])){
$storeid = $_POST['Store'];//grabs store someone is logging in to
$userid = trim($_POST['userID']); //grabs user ID, sql injection cleaning
$userid = strip_tags($userid);
$userid = htmlspecialchars($userid);
$pass = trim($_POST['passhash']); //grabs the user password, sql injection cleaning
$pass = strip_tags($pass);
$pass = htmlspecialchars($pass);
if(empty($storeid)){
$error = true;
$storeError = "Please select a store.";
}
if(empty($userid)){
$error = true;
$useridError = "Please enter your User ID.";
} else if (!filter_var($userid, FILTER_VALIDATE_INT)){
$error = true;
$useridError = "Please enter a valid User ID.";
}
if(empty($pass)){
$error = true;
$passError = "Please enter your password.";
}
//if no errors, continue
if(!$error){
$password = hash('sha256', $pass);
$res=mysqli_query($conn,"SELECT userID, passhash FROM User WHERE userID='$userid'");
$row = mysqli_fetch_array($res);
$count = mysqli_num_rows($res); //if userID and password are correct 1 row should be returned.
$sres=mysqli_query($conn,"SELECT storeID FROM Store WHERE storeID='$storeid'");
$srow = mysqli_fetch_array($sres);
if( $count == 1 && $row['password']==$password){
$_SESSION['user'] = $row['userID'];
$_SESSION['store'] = $srow['storeID'];
$_SESSION["loggedin"] = true;
header('Location: http://http://server-ip/landing.php');
exit();
} else{
$errMSG = "The userID or Password you entered was incorrect. Please try again.";
}
}
}
?>
<!doctype html>
<html lang="en">
<head>
<title>PIMSHOE Login</title>
<!-- Required meta tags -->
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
<!-- Bootstrap CSS -->
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/css/bootstrap.min.css" integrity="sha384-Vkoo8x4CGsO3+Hhxv8T/Q5PaXtkKtu6ug5TOeNV6gBiFeWPGFN9MuhOf23Q9Ifjh" crossorigin="anonymous">
</head>
<body>
<div class="container-fluid jumbotron text-center bg-primary text-white" style="margin-bottom:0">
<h1>PIMSHOE Admin</h1>
</div>
<?php if(isset($useridError) || isset($errMSG) ||isset($storeError) || isset($passError)) { ?>
<div role="alert" class="alert alert-danger text-center">
<?php
if(isset($useridError)) { echo $Error; }
if(isset($passError)) { echo $passError; }
if(isset($errMSG)) { echo $errMSG; }
if (isset($storeError)) { echo $storeError; }
?>
</div>
<?php } ?>
<div class="row mt-5">
<div class="col-sm-4">
</div>
<div class="col-sm-4">
<h2 class="text-center mb-4 mt-1">Sign in</h2>
<form id="loginform" class="form-horizontal" role="form" method="post" action="landing.php" accept-charset='UTF-8'>
<div class="form-group">
<label for="store"></label>
<?php
echo('<select class="form-control" id="store">
<option>Select Store</option>');
$sqli = "SELECT StoreID FROM Store";
$result = mysqli_query($conn, $sqli);
while($row = mysqli_fetch_array($result)){
echo('<option>'.$row['StoreID'].'</option>');
}
echo('</select>');
?>
</select>
</div>
<hr>
<div class="form-group">
<input type="text" name="user_name" class="form-control" maxlength="4" pattern="^[0-9]{4}" id="userID" placeholder="User ID">
</div>
<div class="form-group">
<input type="password" name="user_pass" class="form-control" id="password" placeholder="*********">
</div>
<div class="form-group">
<button id="btn-login" name="btn-login" type="submit" class="btn btn-primary btn-block bg-primary"> Login </button>
</div>
</form>
<!--<a href="" class="float-right btn btn-outline-primary">Sign up</a> Admins insert new users, maybe have it go to a form that sends a request email to an admin?-->
<p class="underlineHover"><a href="#">Forgot password?</a></p>
</div>
</div>
</div>
<!-- Optional JavaScript -->
<!-- jQuery first, then Popper.js, then Bootstrap JS -->
<script src="https://code.jquery.com/jquery-3.4.1.slim.min.js" integrity="sha384-J6qa4849blE2+poT4WnyKhv5vZF5SrPo0iEjwBvKU7imGFAV0wwj1yYfoRSJoZ+n" crossorigin="anonymous"></script>
<script src="https://cdn.jsdelivr.net/npm/popper.js@1.16.0/dist/umd/popper.min.js" integrity="sha384-Q6E9RHvbIyZFJoft+2mJbHaEWldlvI9IOYy5n3zV9zzTtmI3UksdQRVvoxMfooAo" crossorigin="anonymous"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/js/bootstrap.min.js" integrity="sha384-wfSDF2E50Y2D1uUdj0O3uMBJnjuUD4Ih7YwaYd1iqfktj0Uod8GCExl3Og8ifwB6" crossorigin="anonymous"></script>
</body>
</html>
我认为问题出在您的第一个if语句上。
函数isset返回一个布尔值(true或false(，您将其返回值与"进行比较。您可以用以下两种方式之一编写声明：
if(isset($_SESSION['user']) && isset($_SESSION['store'])){
或
if($_SESSION['user']!="" && $_SESSION['store']!=""){