php 如何获取/设置 session_id() 还是应该自动生成？
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How to get/set session_id() or should it be generated automatically?
提问by grai
I have some basic session handling in my application. In each page I check if the user is logged in. If they are then they're already identified by $_SESSION['user_id'], and their login/logout is recorded in a MySQL table.
我的应用程序中有一些基本的会话处理。在每个页面中，我都会检查用户是否已登录。如果是，则他们已被 标识$_SESSION['user_id']，并且他们的登录/注销记录在 MySQL 表中。
I would also like to record visits by guests (not logged in) based on a unique id.
I had assumed that once session_start()is called that an internal session_idis automatically generated and that calling session_id()I could retrieve this. But this just gives an "undefined variable" error, so I guess I have to set it manually..? If so then what's the best way so that it will be a unique ID, or what is the usual method?
我还想根据唯一 ID 记录来宾（未登录）的访问。我曾假设一旦session_start()被调用，内部session_id会自动生成并且调用session_id()我可以检索它。但这只是给出了一个“未定义的变量”错误，所以我想我必须手动设置它..？如果是这样，那么最好的方法是什么，使其成为唯一的 ID，或者通常的方法是什么？
Thanks for any help...
谢谢你的帮助...
回答by Brian
There are 2 ways to use sessions and session id's in PHP:
在 PHP 中有两种使用会话和会话 ID 的方法：
1 - Auto generate the session ID and get it:
1 - 自动生成会话 ID 并获取它：
session_start();
$id = session_id();
2 - Set the session ID manually and then start it:
2 - 手动设置会话 ID，然后启动它：
session_id( 'mySessionId' );
session_start();
If you intend to setthe session ID, you must set it beforecalling session_start();
If you intend to generate a random session_id (or continue one already started in a previous page request) and then getthat id for use elsewhere, you must call session_start()beforeattempting to use session_id()to retrieve the session ID.
如果要设置会话ID，必须在调用session_start()之前设置；如果您打算生成一个随机 session_id（或继续在前一个页面请求中已经开始的），然后获取该 id 以在其他地方使用，您必须session_start()在尝试使用之前调用session_id()来检索会话 ID。
回答by genesis
Here you can see it works for me (session is started silently) : http://sandbox.phpcode.eu/g/f6b6b.php
在这里你可以看到它对我有用（会话是静默启动的）：http: //sandbox.phpcode.eu/g/f6b6b.php
You forgot to start your session, probably
你忘记开始你的会话了，可能
回答by Nausik
Well, it may be a little bit strange, but when I need unique ID I use uniqid()
好吧，这可能有点奇怪，但是当我需要唯一 ID 时，我使用 uniqid()
