使用PHP、jQuery登录网站 - Logging into a site using PHP, jQuery

我正在创建一个需要登录才能做任何事情的网站，流程如下:

用户输入用户名和密码，点击"登录"
用户名和密码发送到JavaScript页面jQuery ajax到另一个php页面处理
PHP脚本处理请求并设置会话变量(' user_logged_in ')为"1"或"0"
根据返回的内容，页面将重新定位到索引页或显示消息

我的问题是，我使用配置文件来确定用户是否使用此会话变量登录，但由于某种原因(尽管变量设置为1)，页面仍然说它不是，代码如下:

主登录页面:

<?php
require_once 'login_config.php';
$alert = false;
if (isset($_GET['alert']) && $_GET['alert'] == "1")
{
    $alert=true;
}
//$_SESSION['user_logged_in'] = false;
//if ($_SESSION['user_logged_in'] == true)
//{
//    header("Location: /");
//}
?>
<!DOCTYPE html>
<html>
<head>
    <title>GWSAM &raquo; Login</title>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <link rel="stylesheet" href="http://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/css/bootstrap.min.css">
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.3/jquery.min.js"></script>
    <script src="http://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/js/bootstrap.min.js"></script>
    <link rel="stylesheet" href="styles/login_style.css" />
    <script src="scripts/login/jquery.login.ajax.js"></script>
</head>
<body class="container-fluid">
    <div class="row">
        <div class="col-sm-3"></div>
        <div class="col-sm-6">
            <h1>GWSAM &raquo; Login</h1>
            <?php if ($alert) { ?><p style="text-align: center;" class="alert alert-danger">You must login to access this.</p><?php } ?>
            <table class="table table-condensed table-bordered table-striped">
                <tr>
                    <td>
                        <label for="username">Username</label>
                    </td>
                    <td>
                        <input type="text" name="username" placeholder="Username" class="form-control" id="username" />
                    </td>
                </tr>
                <tr>
                    <td>
                        <label for="password">Password</label>
                    </td>
                    <td>
                        <input type="password" name="password" placeholder="Password" class="form-control" id="password" />
                    </td>
                </tr>
                <tr>
                    <td colspan="2">
                        <input type="hidden" id="http-host" value="<?=$_SERVER['HTTP_HOST']; ?>" />
                        <button id="login" class="form-control btn btn-primary">Login</button>
                    </td>
                </tr>
            </table>
            <div class="row">
                <div class="col-sm-12"id="loading"></div>
            </div>
        </div>
        <div class="col-sm-3"></div>
    </div>
</body>
</html>
<?=var_dump($_SESSION);?>

JavaScript jQuery ajax页面:

$( document ).ready( function ()
{
    $( "#login" ).on( "click", function ()
    {
        $.ajax( {
            url: "/scripts/login/files/login.php?username=" + $( "#username" ).val() + "&password=" + $( "#password" ).val(),
            type: "GET",
            success: function ( R )
            {
                if ( R == "true" )
                {
                    document.write( '<meta http-equiv="refresh" content="0;URL='''+$("#http-host").val()+'''" />' );
                    window.location.href = $( "#http-host" ).val();
                    return false;
                    //$( "#loading" ).html( '<meta http-equiv="refresh" content="0; URL=index.php" />' );
                    //window.location.href = "index.php";
                    //return;
                }
                $( "#loading" ).html( R );
            },
            beforeSend: function ()
            {
                $( "#loading" ).html( '<p class="alert alert-info" style="text-align: center;">Logging in, please wait.<br /><img src="http://www.iggadget.com/assets/images/loader-1.gif" alt="spinner.gif" height="30" width="30" /></p>' );
            }
        } )
    } );
} );

Ajax页面:

<?php
require_once '../../../login_config.php';
function Login($username, $password)
{
    global $link;
    while ($result = mysqli_fetch_assoc($link->query("SELECT `username`, `password`, `active` FROM `users` WHERE `username`='{$username}';")))
    {
        if ($result['active'] == "NO")
        {
            print '<p class="alert alert-danger" style="text-align: center;">User''s account has been deactived, please contact your network admin</p>';
            $_SESSION['user_logged_in'] = "0";
            return false;
        }
        if ($password == $result['password'])
        {
            $_SESSION['user_logged_in'] = "1";
            return true;
        }
    }
    $_SESSION['user_logged_in'] = "0";
    return false;
}
print Login($_REQUEST['username'], $_REQUEST['password']) ? 'true' : '<p class="alert alert-warning" style="text-align: center;">Cannot login, please try again.</p>';
?>

index.php文件的配置页:

<?php
require_once 'functions/functions.php';
require_once 'functions/database.php';
if (!isset($_SESSION))
    session_start();
$logged_in = isset($_SESSION['user_logged_in']) ? ($_SESSION['user_logged_in'] == "1" ? true : false ) : false;
if (!$logged_in) 
{
    header("Location: login.php");
}
else
{
    //Null action
}
?>

索引页在所有操作完成后显示，但它一直将其发送回登录页…

首先将session_start();写在页面顶部，并尝试如下:

if(isset($_SESSION['user_logged_in'])&&($_SESSION['user_logged_in']==='1'))
{
//if logged in already
}else{
header("Location: login.php");
}

首先将session_start()移动到所有页面的顶部，或者至少是所有使用$_SESSION变量的页面的顶部。最好的办法是将其添加到include中，并将其包含在所有页面中。

在这个脚本中还有一行设置$_SESSION['user_logged_in'] = false;，就在您测试它是否有一个值之前，我假设它在测试中被添加并且没有被删除。

<?php
session_start();
require_once 'functions/functions.php';
require_once 'functions/database.php';
// this line makes NO SENSE so remove it
//$_SESSION['user_logged_in'] = false;

if ( ! isset($_SESSION['user_logged_in']) || $_SESSION['user_logged_in'] == 0)  {
    header("Location: login.php");
}
else
{
    //Null action
}
?>

试试这个代码

<?php
session_start();
require_once 'functions/functions.php';
require_once 'functions/database.php';
$_SESSION['user_logged_in'] = false;
$logged_in = isset($_SESSION['user_logged_in']) ? ($_SESSION['user_logged_in'] == "1" ? true : false ) : false;
if (!$logged_in) 
{
    header("Location: login.php");
    exit;
}
else
{
    //Null action
}
?>