我已经为我的网站创建了一个登录页面。如果数据库中的用户 id 和密码匹配，则将用户定向到 page1.php，但如果用户知道 page1.php 的 URL，则他可以绕过登录页面。我该如何解决这个问题？我知道这个问题是如此微不足道，但我是 Web 开发的新手，无法找到解决这个问题的方法。解决方案似乎是使用 seesion 令牌。但是，我不知道如何使用它来拒绝访问或直接加载 page1.php
<?php
/*** begin our session ***/
session_start();
/*** set a form token ***/
$form_token = md5( uniqid('auth', true) );
/*** set the session form token ***/
$_SESSION['form_token'] = $form_token;
?>
<!DOCTYPE html>
<!--[if lt IE 7]> <html class="lt-ie9 lt-ie8 lt-ie7" lang="en"> <![endif]-->
<!--[if IE 7]> <html class="lt-ie9 lt-ie8" lang="en"> <![endif]-->
<!--[if IE 8]> <html class="lt-ie9" lang="en"> <![endif]-->
<!--[if gt IE 8]><!--> <html lang="en"> <!--<![endif]-->
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
<link rel="stylesheet" href="css/style.css">
<!--[if lt IE 9]><script src="//html5shim.googlecode.com/svn/trunk/html5.js"></script><![endif]-->
</head>
<body>
<form method="post" action="login.php" class="login">
<p>
<label for="username">Username:</label>
<input type="text" name="username" id="username" style="width:300px" required placeholder="enter username" maxlength="20">
</p>
<p>
<label for="password">Password:</label>
<input type="password" name="password" id="password" style="width:300px" required placeholder="enter password" maxlength="20">
</p>
<p class="login-submit">
<input type="hidden" name="form_token" value="<?php echo $form_token; ?>" />
<button type="submit" class="login-button" value="→ Login">Login</button>
</p>
<p class="forgot-password"><a href="index.html">Forgot your password?</a></p>
</form>
<sup style="color:#777; padding-left:550px;"> ** both username and password must be alpha-numeric between 4-20 characters</sup>
</body>
</html>
这是我处理登录表单输入的 php 文件
<?php
/*** begin our session ***/
session_start();
/*** check if the users is already logged in ***/
if(isset( $_SESSION['user_id'] ))
{
$message = 'Users is already logged in';
}
/*** check that both the username, password have been submitted ***/
if(!isset( $_POST['username'], $_POST['password']))
{
$message = 'Please enter a valid username and password';
}
/*** check the username is the correct length ***/
elseif (strlen( $_POST['username']) > 20 || strlen($_POST['username']) < 4)
{
$message = 'Incorrect Length for Username';
}
/*** check the password is the correct length ***/
elseif (strlen( $_POST['password']) > 20 || strlen($_POST['password']) < 4)
{
$message = 'Incorrect Length for Password';
}
/*** check the username has only alpha numeric characters ***/
elseif (ctype_alnum($_POST['username']) != true)
{
/*** if there is no match ***/
$message = "Username must be alpha numeric";
}
/*** check the password has only alpha numeric characters ***/
elseif (ctype_alnum($_POST['password']) != true)
{
/*** if there is no match ***/
$message = "Password must be alpha numeric";
}
else
{
/*** if we are here the data is valid and we can insert it into database ***/
$username = filter_var($_POST['username'], FILTER_SANITIZE_STRING);
$password = filter_var($_POST['password'], FILTER_SANITIZE_STRING);
/*** now we can encrypt the password ***/
// $password = sha1( $password );
/*** connect to database ***/
/*** mysql hostname ***/
$mysql_hostname = 'localhost';
/*** mysql username ***/
$mysql_username = 'abcdefg';
/*** mysql password ***/
$mysql_password = 'abcdefg';
/*** database name ***/
$mysql_dbname = 'abcdefg';
try
{
$dbh = new PDO("mysql:host=$mysql_hostname;dbname=$mysql_dbname", $mysql_username, $mysql_password);
/*** $message = a message saying we have connected ***/
/*** set the error mode to excptions ***/
$dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
/*** prepare the select statement ***/
$stmt = $dbh->prepare("SELECT username, password FROM user
WHERE username = :username AND password = :password");
/*** bind the parameters ***/
$stmt->bindParam(':username', $username, PDO::PARAM_STR);
$stmt->bindParam(':password', $password, PDO::PARAM_STR, 40);
/*** execute the prepared statement ***/
$stmt->execute();
/*** check for a result ***/
$user_id = $stmt->fetchColumn();
echo $user_id;
/*** if we have no result then fail boat ***/
if($user_id == false)
{
$message = 'Login Failed';
}
/*** if we do have a result, all is well ***/
else
{
/*** set the session user_id variable ***/
$_SESSION['user_id'] = $user_id;
/*** tell the user we are logged in ***/
$message = 'You are now logged in';
echo '<script>window.location = "http://127.0.0.1/university/site/page1.php"</script>';
}
}
catch(Exception $e)
{
/*** if we are here, something has gone wrong with the database ***/
$message = 'We are unable to process your request. Please try again later"';
}
}
?>
<html>
<head>
<title> Login</title>
</head>
<body>
<p><?php echo $message; ?>
</body>
</html>