是否可以在php中为session_id（）赋值？

Question

Is it possible to assign session_id() a new value manually?

I've tried the following but it's not working:

session_start();
$sessionId = session_id();
echo $sessionId;

if ($sessionId != $ses) { 
session_id() = $ses;
}

Answer 1

You can using session_id() :

session_id($sessionId);

session_id() can be used to either get the session ID or set it by passing in an optional function argument as I have done above.

It is worth noting the following from the manual with regard function call order and session ID character restrictions:

If id is specified, it will replace the current session id. session_id() needs to be called before session_start() for that purpose. Depending on the session handler, not all characters are allowed within the session id. For example, the file session handler only allows characters in the range az AZ 0-9 , (comma) and - (minus)!

Answer 2

You have to assign the id BEFORE you start the session.

session_id('hello');
start_session();

However, be careful doing this. The session ID is (generally) a long random alphanumeric string. if you set it to something constant/simple, you've made it much much easier for someone to hijack your users' sessions.

And if two or more people get the same session ID, they'll be SHARING the same session, since this ID is the unique identifier for a particular session. It should be unique for every user, with no duplicates.

Answer 3

是的，按照手册，您只需提供一个字符串作为session_id([string $id])的参数即可