$ _SESSION值不成立！ [英] $_SESSION values not holding!

问题描述

我正在编写一个用户登录系统，我(和许多其他人一样)在会话方面遇到问题.

I'm writing a user login system, and I (like so many others) am having a problem with my sessions.

这是验证输入后登录脚本的指针:

Here's the pointer from the login script when the inputs are validated:

session_start();
$_SESSION['id']=$id;
header('location: memberhome.php');

这是memberhome.php上的第一件事:

Here's the first thing on memberhome.php:

<?php
session_start();
$id=$_SESSION['id'];
?>

稍后在memberhome.php中:

And later in memberhome.php:

You are logged in as: <?php echo $id; ?>

问题是$ _SESSION ['id']显然是空的，因此回显$ id没有显示任何内容.

The problem is $_SESSION['id'] is apparently empty so the echo $id prints nothing.

另一种无效的方法:

//removed session_start and $_SESSION bit from the top
You are logged in as: <?php session_start(); echo $_SESSION['id']; ?>

现在，这是奇怪的部分.此方法有效:

NOW, here's the weird part. This method DOES work:

You are logged in as: <?php echo session_start();$_SESSION['id']; ?>

您可以看到session_start()在回显之后被移动了.当页面从登录脚本加载时有效.但是，刷新后，它将不再起作用.

You can see the session_start() is moved AFTER the echo. This works when the page loads from the login script. However, upon refresh, it does NOT work once again.

我尝试了很多替代方法，并花了几个小时来寻找先前问题的答案.我还查看了phpinfo()的内容，但没有发现任何问题.这完全是我的进步.谢谢！

I've tried a bunch of alternatives and spent a few hours searching for answers in previous questions. I also looked at my phpinfo() for something fishy and found nothing. This is entirely what my progress is hinging on. Thanks!

推荐答案

首先，请启用调试:

error_reporting(E_ALL);
ini_set('display_errors', '1');

第二，session_start()必须位于页面顶部.所以你写的那行；

Second, session_start() needs to be at the top of the page. So the line you wrote;

You are logged in as: <?php echo session_start();$_SESSION['id']; ?>

将永远无法工作.

在任何HTML等之前，以下行必须位于页面顶部.

The following line needs to be on top of the page, before any HTML etc.

<?php
session_start();
$id=$_SESSION['id'];
?>

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