小贝子编程

会话启动错误但不知道如何解决



当我在将网站上传到我的网络服务器后重新加载我的网站时，我的网站上出现以下错误：

警告：session_start((：无法发送会话缓存限制器 - 标头 已发送(输出开始于/data/userfiles/websites/lagersystem/login.php：1( in/data/userfiles/websites/lagersystem/login.php 在第 36 行

我不知道如何解决这个问题。

这是我的源代码： 

<html>
<head>
<title>Login</title>
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous">
<link rel="icon" type="favicon.gif" href="favicon.gif" sizes="256x256">
</head>
<body>

<div class="p-3 mb-2 bg-secondary text-white">
<nav class="navbar navbar-expand-lg navbar-light bg-light">
<a class="navbar-brand" href="index.php"><img src='favicon-64.gif'/></a>
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse" id="navbarSupportedContent">
<ul class="navbar-nav mr-auto">
<li class="nav-item active">
<a class="nav-link" href="index.php">Home<span class="sr-only">(current)</span></a>
</li>
<li class="nav-item">
<a class="nav-link" href="add.php">Hinzufügen</a>
</li>
<li class="nav-item">
<a class="nav-link" href="login.php">Admin</a>
</li>
</ul>
</div>
</nav>
</div>
<?php 
session_start();
$pdo = new PDO('mysql:host=localhost;dbname=', '', '');
if(isset($_GET['login'])) {
$email = $_POST['email'];
$passwort = $_POST['passwort'];
$statement = $pdo->prepare("SELECT * FROM ls_users WHERE email = :email");
$result = $statement->execute(array('email' => $email));
$user = $statement->fetch();
//Überprüfung des Passworts
if ($user !== false && password_verify($passwort, $user['passwort'])) {
$_SESSION['userid'] = $user['id'];
die('<div class="text-center">Login erfolgreich. Weiter zu <a href="sicherheit.php">internen Bereich</a></div>');
} else {
$errorMessage = "E-Mail oder Passwort falsch!<br>";
}
}
?>
<?php 
if(isset($errorMessage)) {
echo $errorMessage;
}
?>
<div class="row align-items-center justify-content-center">
<div class="text-center">
<form action="?login=1" method="post">
E-Mail:<br>
<input class="form-control" type="email" size="40" maxlength="250" name="email"><br><br>
Dein Passwort:<br>
<input class="form-control" type="password" size="40"  maxlength="250" name="passwort"><br>
<input class="form-control" type="submit" value="Anmelden">
</form> 
<br />
<br />
</div>
</div>


<div class="p-3 mb-2 bg-secondary text-white">
<div class="row">
<div class="col">
<div class="text-center">
<a href="index.php" class="btn btn-dark">Aktualisieren</a>
</div>
</div>
<div class="col">
<div class="text-center">
<a href="fehler.php" class="btn btn-danger">Fehlermeldung</a>
</div>
</div>
</div>
</div>
<div class="p-3 mb-2 bg-secondary text-white">
<footer class="mainfooter" role="contentinfo">
<div class="footer-top p-y-2">
<div class="container-fluid">
</div>
</div>
<div class="footer-middle">
<div class="container">
<div class="footer-bottom">
<div class="container">
<div class="row">
<div class="col">
<!--Footer Bottom-->
<p class="text-center">&copy; 2018 - All rights reserved.</p>
</div>
</div>
</div>
</div>
</footer>
</div>
<script src="https://code.jquery.com/jquery-3.2.1.slim.min.js" integrity="sha384-KJ3o2DKtIkvYIK3UENzmM7KCkRr/rE9/Qpg6aAZGJwFDMVNA/GpGFF93hXpG5KkN" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.9/umd/popper.min.js" integrity="sha384-ApNbgh9B+Y1QKtv3Rn7W3mgPxhU9K/ScQsAP7hUibX39j7fakFPskvXusvfa0b4Q" crossorigin="anonymous"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js" integrity="sha384-JZR6Spejh4U02d8jOt6vLEHfe/JQGiRRSQQxSfFWpi1MquVdAyjUar5+76PVCmYl" crossorigin="anonymous"></script>
</body>
</html>

谢谢。

你必须用

<?php 
session_start();

原因是会话通过 cookie 工作(如果客户端从未存在过，PHP 会发送一个随机数作为 cookie。然后，每当客户端返回时，他都会发送该cookie，PHP可以查找该用户的$_SESSION(。

问题是 cookie 必须在标头中发送，然后才能通过任何 HTML，因此如果您执行以下操作：

<html> <?php session_start();?>

PHP 会读取你的文件，看到你写了 "，认为不需要再写任何标头，然后从其余的开始。然后当它击中session_start时，它不能再回头并给你错误。

喜欢这个：

<?php session_start();?>
<html>
<head>
<title>Login</title>
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous">
<link rel="icon" type="favicon.gif" href="favicon.gif" sizes="256x256">
</head>
<body>

<div class="p-3 mb-2 bg-secondary text-white">
<nav class="navbar navbar-expand-lg navbar-light bg-light">
<a class="navbar-brand" href="index.php"><img src='favicon-64.gif'/></a>
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse" id="navbarSupportedContent">
<ul class="navbar-nav mr-auto">
<li class="nav-item active">
<a class="nav-link" href="index.php">Home<span class="sr-only">(current)</span></a>
</li>
<li class="nav-item">
<a class="nav-link" href="add.php">Hinzufügen</a>
</li>
<li class="nav-item">
<a class="nav-link" href="login.php">Admin</a>
</li>
</ul>
</div>
</nav>
</div>
<?php 
$pdo = new PDO('mysql:host=localhost;dbname=', '', '');
if(isset($_GET['login'])) {
$email = $_POST['email'];
$passwort = $_POST['passwort'];
$statement = $pdo->prepare("SELECT * FROM ls_users WHERE email = :email");
$result = $statement->execute(array('email' => $email));
$user = $statement->fetch();
//Überprüfung des Passworts
if ($user !== false && password_verify($passwort, $user['passwort'])) {
$_SESSION['userid'] = $user['id'];
die('<div class="text-center">Login erfolgreich. Weiter zu <a href="sicherheit.php">internen Bereich</a></div>');
} else {
$errorMessage = "E-Mail oder Passwort falsch!<br>";
}
}
?>
<?php 
if(isset($errorMessage)) {
echo $errorMessage;
}
?>
<div class="row align-items-center justify-content-center">
<div class="text-center">
<form action="?login=1" method="post">
E-Mail:<br>
<input class="form-control" type="email" size="40" maxlength="250" name="email"><br><br>
Dein Passwort:<br>
<input class="form-control" type="password" size="40"  maxlength="250" name="passwort"><br>
<input class="form-control" type="submit" value="Anmelden">
</form> 
<br />
<br />
</div>
</div>


<div class="p-3 mb-2 bg-secondary text-white">
<div class="row">
<div class="col">
<div class="text-center">
<a href="index.php" class="btn btn-dark">Aktualisieren</a>
</div>
</div>
<div class="col">
<div class="text-center">
<a href="fehler.php" class="btn btn-danger">Fehlermeldung</a>
</div>
</div>
</div>
</div>
<div class="p-3 mb-2 bg-secondary text-white">
<footer class="mainfooter" role="contentinfo">
<div class="footer-top p-y-2">
<div class="container-fluid">
</div>
</div>
<div class="footer-middle">
<div class="container">
<div class="footer-bottom">
<div class="container">
<div class="row">
<div class="col">
<!--Footer Bottom-->
<p class="text-center">&copy; 2018 - All rights reserved.</p>
</div>
</div>
</div>
</div>
</footer>
</div>
<script src="https://code.jquery.com/jquery-3.2.1.slim.min.js" integrity="sha384-KJ3o2DKtIkvYIK3UENzmM7KCkRr/rE9/Qpg6aAZGJwFDMVNA/GpGFF93hXpG5KkN" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.9/umd/popper.min.js" integrity="sha384-ApNbgh9B+Y1QKtv3Rn7W3mgPxhU9K/ScQsAP7hUibX39j7fakFPskvXusvfa0b4Q" crossorigin="anonymous"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js" integrity="sha384-JZR6Spejh4U02d8jOt6vLEHfe/JQGiRRSQQxSfFWpi1MquVdAyjUar5+76PVCmYl" crossorigin="anonymous"></script>
</body>
</html>

相关内容

最新更新


热门标签：

javascript python java c# php android html jquery c++ css ios sql mysql arrays asp.net json python-3.x ruby-on-rails .net sql-server django objective-c excel regex ruby linux ajax iphone xml vba spring asp.net-mvc database wordpress string postgresql wpf windows xcode bash git oracle list vb.net multithreading eclipse algorithm macos powershell visual-studio image forms numpy scala function api selenium